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avr:master avr:main avr:stk500v2-library-wip avr:autobaud
avr:v8 avr:v7 avr:v6 avr:v5 avr:v4 avr:v3 avr:v2 avr:v1
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avr:v8 avr:v7 avr:v6 avr:v5 avr:v4 avr:v3 avr:v2 avr:v1

131 Commits
6f9d8bae42 ... main

Author SHA1 Message Date
BlackMark
20b1485b6f deps: the pin advances to the identity check that reads its own sibling 
libavr 93d8b0e. The check is handed the sibling build tree now and asks its build system whether the image is current, so a comparison against a tree the run did not build skips rather than passing. Gated at the pin.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-09-03 08:24:00 +02:00
BlackMark
b759618024 deps: the pin advances again, and the line ending stops being the editing machine's 
The libavr pin moves to the preset loop's own fix. `tools/check-presets.sh` -
which this repository's gate calls - parsed `cmake --list-presets` by anchoring
a preset name's closing quote to the end of the line, and a preset carrying a
`displayName` is listed as `"name" - description`. The presets here are
undescribed, so the loop found them either way; one `displayName` away it would
have found none and said the repository had no presets. The loop has a test
aimed at it now, which it did not before - libavr runs none of its own presets
through it.

`.gitattributes` gains `* text=auto eol=lf`. Naming the source extensions left
Markdown, Python, shell and CMake to whatever wrote them, and on the Windows
side of this bench that is CRLF - which turns an eighty-line edit into a rewrite
of every file it touched and buries the change in the diff. Rule 50 carries the
sentence now, so it is the repository's default rather than a habit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-09-03 03:27:00 +02:00
BlackMark
22f17b5a25 deps: the libavr pin advances, and a toolchain path stops being committed 
The pin moves to libavr's USI I2C rate fix and to the two override surfaces the
fan-controller port filed - a PWM solve that can be pinned, and a capture edge
that is a value rather than a template argument. The four TinySafeBoot tiers
name none of them, and no image moved.

`.vscode/settings.json` stops naming a toolchain prefix. It named
`D:/dev/libavr/local/toolchain/avr-gcc-16.1.0-mingw`: a path true of one machine
(libavr guidance rule 50) and, since the in-repo toolchain copies went, true of
none - so a window opening this folder was being pointed at a directory that
does not exist. `local/machine.cmake` is where a checkout says that, and it
already did.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-09-03 02:39:43 +02:00
BlackMark
243b258d4d deps: the libavr pin advances, and a check its host cannot run skips rather than going missing 
The protocol tests are registered on every host now and skip where the simavr
device cannot be built. They used to be left out of the suite entirely, which
makes its size a property of the machine - and a suite whose size is a property
of the machine is one nothing can be compared against.

The reason travels with the skip: no compiler, no Python, or one bounded line
of whatever stopped test/device.cpp from linking, so the reading says what is
absent rather than that something is.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-09-02 18:00:38 +02:00
BlackMark
9575145f0d deps: the libavr pin advances to the compare-debug fix 
One commit, and it is the host check script this repo runs on every target
plus its own new test: `check-compare-debug.py` was splitting each recorded
compile command with POSIX rules, which eat a Windows compiler path, so that
check died here rather than reporting. Nothing a device image is compiled from
moved, and the comparison says so - every image this repo builds is
byte-for-byte the one it built at the previous pin.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-09-02 10:47:12 +02:00
BlackMark
d8211ff440 deps: the libavr pin advances 11 commits 
All four TinySafeBoot tiers **byte-identical**: 776 B pure, 630 B policy,
528 B tricks, 512 B asm. The size gradient those tiers exist to measure is
therefore unchanged, which is the property worth checking here - the tiers are
a measurement, and a pin that moved one would move the finding.

Five checks green; the format check skips where there is no clang-format.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-09-02 10:15:52 +02:00
BlackMark
c004d1bdb9 build: the libavr pin advances 43 commits 
Both producers, because a pin this far forward is exactly the change whose other
one has to be compiled rather than assumed: nine tests on the generated side -
the format check, the four size canaries, the four simulator-driven protocol
runs - and `--full`'s reflect build of the same TUs. The four tiers agree in
`.text` across both, asm 512 B, tricks 528, policy 630, pure 776, with the asm
reference still exactly on the slot.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
 2026-08-25 19:13:43 +02:00
BlackMark
7172d1fc64 build: the libavr pin advances to the i2c fix 
e697920. The tiers hold no i2c bus, so nothing here moves; the pin advances so
the whole org names one library. Gate green: nine tests, four tiers at their
section sizes and each one's protocol suite.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-23 06:26:47 +02:00
BlackMark
7c1a6a140b pureboot moves to its own repo 
pureboot is at git.blackmark.me/avr/pureboot now, with its own history: the
files it kept in pureboot/ sit at the top level there, its CMakeLists is the
merged whole of that unit and the build around it, and the v1..v8 tags moved
with it - each one checks out and compiles to exactly the .text it compiled to
here. The loader that repo builds is byte-identical to the one this commit
removes, verified before the removal rather than after.

Nothing is rewritten on this side. The history and the tags are untouched, so
every commit before this one still has pureboot in it and still builds it;
this is one commit that stops carrying it forward.

What goes with it: the four pureboot files, the thirteen pb*.py protocol
drivers and their four host-side unit tests, pbapp and the pureboot simavr
runner, check_pi.py, pbhw.py, pbrig.py, sizes.py, and the Studio project.
check_unit.cmake goes too - it had no caller left once the unit tests moved.

What is left is the four TinySafeBoot tiers, and the build shrinks to fit
them: 757 lines of CMakeLists to 137, and the preset matrix from 37 chips to
one, because the tiers reimplement an ATmega328P-only protocol and every other
chip in that list was there for pureboot. check.sh loses its size-table pass -
the table it checked was pureboot's README - and the Studio solution loses the
project that is now in the other repo.

Gate green: nine tests, four tiers at their section sizes and each one's
protocol suite against the simulator.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-23 06:05:45 +02:00
BlackMark
bf9b86d2fc build: the libavr pin advances 29 commits, and selfwrite stops being flaky 
dc1e87d -> aec9955. Every generated workflow green on all 37 chips, and no
image moves: this loader uses uart, spm, eeprom and startup, and the library's
advance is in i2c, the uart ring's field order, percent_t's constructor and a
spare-vector stub, none of which pureboot links.

The gate came back red on atmega16 and atmega32a, both pureboot.selfwrite, and
the advance is not why. Measured at both pins over twenty runs each: 2/20 red
at dc1e87d and 1/20 at aec9955, so the flake predates the pin and the eight
clean runs that first suggested otherwise were luck.

The cause is in the test. It writes the sealed erase and waits with
read_exact(2, 2.0) - but the loader issues its verdict *before* the SPM, as
the comment above that line already said, so the reply arrives while the erase
has not happened and device.stop() then races it. That is why every failure
was fast (0.39 s, 0.64 s) and every pass slow (2.44 s): the runs that passed
were the ones whose read timed out. The second mode is the same race seen from
the host - the loader erases its own command loop mid-reply, the pty closes,
and errno 5 escapes an except that names only pb.Error.

So the wait is a settle nothing may shorten, and a closing pty ends it rather
than escaping it. A fixed settle is still wall clock against the simulator's
progress through it, which is load-dependent - it measured 1/10 red with the
machine saturated - so the scenario is attempted with a doubling budget and
the claim stays exact: a loader that does not erase fails every attempt.

0/30 quiet and 0/20 with all four cores saturated, against 2/20 before.
Red-checked by settling for zero, which still reports the erase never landed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-23 03:06:12 +02:00
BlackMark
238fb2919c build: the libavr pin advances over the inlined vector 
The advance that flattens a vector's handler cannot reach a loader: not one
of the 13523 images the presets build defines a vector at all. Measured
rather than argued - every one of them is byte-identical across the advance,
and the 37-chip gate is green with the README's size table matching all 15
rows.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-16 19:59:25 +02:00
BlackMark
1541818254 test: the walk fixture states the board's fuses, not an approximation of them 
The profile called the ssd1306 board's own read ff ff ff dc; the part reads
ff ff fd dc - an Atmel-ICE and the loader agree on that byte. Only the high
fuse decides the walk region, so nothing about the refusal changes; the
fixture now names a configuration that was read off hardware.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-16 04:49:51 +02:00
BlackMark
37f9747e26 fix: --flash never ran the brick guard, because it never read the fuses 
check_walk_region() refuses an image writing into the span reset crosses to
reach the loader, and a plain --flash never ran it: the fuses were read for
--fuses and for --update-loader, so the tool read them to protect the loader
and never to protect the reset path. It cost an ssd1306 board - an application
grown through 0x7c00 on a 328P with hfuse 0xdc, reset landing mid-function,
an ICE the only way back.

The check now fetches its own input, so the operation that asks for no fuses
cannot skip it and neither can a direct API caller: pbdirty and pbmute call
op_flash() as a library and are guarded without a line changing in them.
Fuses that cannot be read are a refusal naming --assume-fuses and --force,
because unknown is not empty.

The rig had to stop lying first. The fuse read is an LPM diverted by BLBSET,
which simavr executes straight out of flash with no hook, so a fuse read
answered flash bytes and --fuses had been printing them on every chip. The
runner models the diversion at the SPMCSR write, -f states the profile - and
stores the register itself, since a registered handler replaces simavr's store
and would otherwise swallow every SPM command on the cores where nothing else
watches it.

pureboot.walk reproduces the brick: the unfixed tool writes 249 pages through
0x7c00 in silence, the fixed one refuses.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-16 03:56:20 +02:00
BlackMark
6ff407e7bb chore: machine-local state has a home here too 
Guidance rule 15 puts every machine-local artefact under a gitignored local/,
and this repo could only have committed one.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-16 03:56:08 +02:00
BlackMark
cbb3c58300 test: the format and ASCII rules stop being a habit here too 
libavr's guidance binds this repo, and its gate checked every chip's codegen
without ever checking whether the sources it compiled were clang-format clean
or ASCII. `libavr_format_test()` does both now, over this tree alone - the
oracle's assembly needs no exclusion, being in neither glob, which is the right
answer for a vendored reference whose text is the artifact.

The sizes this repo prints were already gated: `sizes.py check-readme` is the
shape the rest of the fleet has now copied.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-12 23:20:36 +02:00
BlackMark
c4b7769f84 build: the libavr pin advances to the sweep's own record 
Documentation only - the guideline sweep's condensed entry, the three measured
facts about class-type constants it produced, and the port filings it left
open. No header, tool or generated input moves, so every image is untouched.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-12 17:02:53 +02:00
BlackMark
735ffab7dc fix: the four tiers stop describing features they do not have, and three gates start failing 
The reading pass over this repo found the tiers disagreeing with themselves,
and every fix here was measured.

**The turn-around guard is real code.** `tsb_asm` and `tsb_tricks` wrote
`for (std::uint8_t guard = 46; guard; --guard) ;` between taking the one-wire
line and the first UDR0 store, under a comment naming it a turn-around guard.
It has no side effect, so GCC deleted it - `sts UCSR0B` went straight to
`sts UDR0` - while the hand-written oracle spends six bytes on that wait and
libavr's own half-duplex spends them through `delay::cycles`. Two of four
tiers described a feature they did not have, which made the size gradient a
comparison between different loaders. `avr::delay::cycles<one bit time>()`
bottoms out in asm and cannot be deleted.

**The entry belongs to the library, and hand-rolling it was expensive.** Three
tiers wrote their own naked `.vectors` stub with `asm volatile("clr
__zero_reg__")` - which design.md fences to libavr and never a port, and which
`tsb_tricks` denied having in its own title line. `avr::startup::entry` also
keeps the body `noinline` for a stated reason: avr-ld must not shrink a
`.vectors` section, so a loader inlined into one forfeits call relaxation
everywhere. `tsb_pure` came out **836 -> 734** bytes for that alone.
`stack::hardware` - the reset value this part guarantees, with the write kept
where a part does not - saved another four, which is what let `tsb_asm` afford
the guard it had been four bytes short of. It fills its 512-byte section
exactly now, with the whole feature set.

**`tsb_pure` had no receive timeout.** Its `rx()` was `read_blocking()`, so a
silent host wedged the password gate and the command loop forever - the one
fix the oracle's own header lists by name, and one the other three tiers
implement. It is bounded now, and 0-on-silence falls through every compare as
theirs does.

Three gates could pass without proving anything. `sizes.py check-readme`
reported a match when every row's lookup missed; `check_size.cmake` used
`CMAKE_MATCH_1` without checking the match succeeded, which is the guard its
sibling `check_unit.cmake` has and it is the size gate; `check_pi.py` raised
IndexError instead of reporting a position-independence break that changed the
image's length. And `check.sh` spelled the 37-chip list a second time beside
make_presets.py, where a chip added to one and missed in the other is a
silently unbuilt chip - it reads the presets now, and produces the same 37 and
12.

tsbtest.py gains the scenario nothing covered: a wrong password byte must
neither activate the loader nor reach the emergency erase behind it. Red-green
on a tier with the refusal removed.

Smaller, all measured or checked: the signature is `hw::db.signature` in every
tier as the page size and EEPROM end beside it already were; `act_min` derives
from the clock; pureboot.py's `rjmp` helpers refuse a part past rjmp's
4096-word reach rather than silently folding an offset (unreachable today, the
ATtiny85 sits exactly on it); the host tool calls space 2 `data` as the wire
and the loader do; `.clangd` strips the fifth GCC-only flag the build passes;
pbrig's bitclock guard reads its own ladder; pbreloc's unexplained retry is
gone, the write being reliable on five runs without it; and the four tier
sizes live in oracle/README.md's table instead of four file headers and a
CMake comment.

`--poke` before `--peek` turned out to be right - pbtest.py round-trips a poke
through the peek behind it - so the parser order and README say so now.

Every chip green, the README size table matching every image.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-12 16:41:50 +02:00
BlackMark
be78f38f3f build: the libavr pin advances past the audit sweep, and two gates start meaning something 
The pin crosses libavr's phase-6 close and the guideline sweep behind it.
All 37 chips green, 43 tests each, the README size table matching every
built image, and all 13602 flash images byte-identical to the previous pin.

The bump broke one gate and exposed another as ornamental.

`check_unit.cmake` matched the autobaud loader's measured unit by the symbol
`unit_E`; libavr's rule-46 sweep renamed the member to `m_unit`, which the
mangling spells `6m_unitE`. On the RAM-home chips the check went red and said
so. On the GPIOR chips it went green - the branch that asserts the unit is
*not* in RAM passes on an empty match, and an empty match is what a stale
regex returns for every image. Both branches mean something again.

`tools/check.sh` ran the 37-chip loop under `set -e`, so the first red chip
ended the gate and the 36 behind it were never built - a stale size canary on
attiny13 would have been an alibi for every loader after it. It accumulates
now and fails at the end naming every red preset, which is the shape libavr's
own check.sh carries and the reason it carries it.

The port's own sweep, verified by byte identity: the four TSB tiers' 16-byte
info block is `std::to_array` rather than an extent written beside the
sixteen elements the compiler can count, the three-member serial and loader
configs break one member per line, the turn-around loops are braced, and the
test fixture's config pair is a deduced `std::array` (rules 36, 40, 34). Two
comments stop narrating how the code came to be and one stops citing a repro
at a path it left two phases ago (rules 12, 13).

pureboot's identity stamp stays the raw array rule 36 bans, and now says why:
its reads must fold to immediates because the bytes are in program memory and
a formed address is dereferenced as data space. As a `std::array` the read
loop stopped unrolling and emitted exactly that - measured at +8 B and a
wrong answer on the wire.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-12 15:05:07 +02:00
BlackMark
d3d8d07905 editor: clangd and cmake work from a committed vscode workspace 
The three files libavr's consumers carry, in the vendored shape: this repo
rides as a submodule (wateralarm), so .clangd names no database -- the
checkout that is opened as a folder names build/atmega328p-generated in
.vscode/settings.json -- and holds the stand-ins clang needs for GCC's AVR
dialect plus the removals for the codegen flags the loader TUs carry and
clang has no spelling for (-fira-algorithm, -fno-split-wide-types,
-fno-tree-ter, -fno-ivopts). The libavr pin advances to the editor-audit
fixes. The preset builds green from the pin and clangd reports zero errors
on pureboot.cpp.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-08-09 16:49:01 +02:00
BlackMark
b4243a89a3 docs: the one-wire section's sizes catch up with v9 
The v9 update moved the size table and the tightest-fit paragraph and
missed this section: the autobaud + OSCCAL twins measure 480 now, not
502, and the hardware half-duplex trio is 392/428/440. The claims
around the numbers were true all along - one-wire still measures the
same as two-wire, and the +42..50 delta over stock still holds exactly.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-08-09 16:35:55 +02:00
BlackMark
e4390d2ba8 build: the libavr pin advances past phase 6, at byte parity everywhere 
The pin crosses libavr's phase 6 - the renamed system surface, the named
serial configs, the receiver-tolerance table, the paged SPM receipts -
and every loader image comes out size-identical: the full matrix on six
representative chips (the exhaustive cross product on three of them),
the stock and autobaud columns untouched, the four tsb tiers back on
their recorded floors at 510/526/638/836.

Byte parity was not free, and the two libavr defects it surfaced were
fixed there rather than absorbed here. The EEPROM write procedure's
step 2 - the SPMEN spin - had landed unconditionally and cost every
build six bytes for a wait a polled loader can never take; it is scoped
now, and the loaders state the datasheet's own omission clause
(spm_interlock::omitted, DS40002061B 8.6.3). The blocking page
erase/write grew an internal wait the tiers' settle() already provides,
so the tiers issue the command form and pureboot keeps its host-driven
sp_spm path.

What the port states rather than inherits: the stock 115200 at 16 MHz
sits +2.1 % past the receiver-tolerance table libavr now holds rates
to, so the hardware links say .allow_baud_error = true - the same
2.5 % envelope pureboot_baud_feasible() has always enforced, proven on
silicon across the fleet. rx_ready() reads readable() now.

Alongside the pin: rule 33's ASCII sweep over every source (docs keep
their typography), rule 34's InsertBraces in .clang-format with the
tree reformatted, std::array over the simavr runners' raw buffers, and
the stale Studio size in ide/README.md replaced by the claim its
check-flags gate actually holds.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-08-09 11:43:44 +02:00
BlackMark
0cb83ff36f build: the libavr pin advances past the consumer-report fixes 
timer::engine gains stop()/start() and a runtime TOP, adc gains
disable()/enable(), and libavr_programming_targets() stops leaving .fuse bytes
in the flash HEX. Every one of them is additive, and this port adopts none of
them yet: its 687 built images come out byte-identical across the pin change,
which is what the advance is here to keep true.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-01 23:18:55 +02:00
BlackMark
8aa1721709 README: which slot the 510 bytes belong to, and the way in without a reset 
The Chips footnote said "the slot's last word" against a table whose subject is
the loader, where it means the *lower* slot's — the trampoline holding the
application's relocated reset vector, and a staging copy's own last word during
a self-update. The resident has all 512 bytes of the slot it runs in; 510 is
what an image must fit so a copy staged one slot down leaves that word alone.

And a section on entering from a running application, for the boards whose
adapter does not drive reset and which therefore have no edge to open a window
with. Deciding when to jump stays the application's business — a console
command, a held pin, an idle timeout — so there is no knock detector and no
header here, only the mechanics: the base as a --defsym symbol, and the three
things that must be true first (interrupts off, WDRF clear, and any peripheral
holding the link released, since a loader entered by a jump inherits the
application's registers rather than reset values).

Not the noipa indirect call run_app() uses, which is the obvious thing to copy
and the wrong one: that is a position-independence measure belonging to a loader
that runs the same image from either slot. An application is linked at a fixed
base, so a plain call to the symbol comes out `call 0x7e00` in four bytes where
the laundered form spends two ldi's and a helper call.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-01 23:12:34 +02:00
BlackMark
2655d058f4 pbhw: an absent probe is not a destroyed loader 
The slot-survives-erase check reads back over ISP by design — an independent
reader is the only witness worth having about a loader that has just been
asked to erase around itself. With the one probe on another board it printed
"ISP read failed" as a red, which is the same word a destroyed loader would
get, and it is permanently red on the two deployments with no ISP header at
all.

It names its witness now and falls back to the link when there is no
programmer, saying that the loader is then reporting on its own slot — weaker
for exactly the reason it is worth having, since a destroyed loader could not
answer at all. An absent instrument is a fact about the bench and a wrong byte
is a verdict on the subject; a check that prints them identically stops being
read.

Both paths exercised on hardware: ISP on the Uno, the link on the ATtiny13A.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-01 20:25:47 +02:00
BlackMark
e9c3897d4f build: the libavr pin advances to the v9 era 
Built and tested against it in a clean checkout of this port, through its own
submodule rather than a working-tree override, so the pin is what was proved.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-01 18:48:31 +02:00
BlackMark
546b1589a3 pureboot v9: seal every command, and stop guarding what the seal covers 
'W' handed the loader a whole page with no ack inside it and sp_spm handed any
wire byte to SPMCSR, so a dropped byte re-aligned the stream and page data
arrived where commands belong. That is how a page-address byte became
BLBSET|SELFPRGEN on the tempmon board and programmed its lock bits.

The first answer was to refuse that one command. It was the wrong shape twice
over: it forbade a lock-bit write the owner may want, and it left every other
command decided by bytes nobody checked. v9 checks them instead. One header for
every command — opcode, selector, address, count, seal — folded and compared
before the command is decoded, and *answered* before any payload moves: '+'
accepts, 0xd4 (the ack inverted) refuses and nothing happened. An ack cannot do
this job; it reports a command that has already run.

It is smaller than v8 everywhere: 1284P 506→480, m8 498→480, 328P 484→468,
t13A 474→460. The seal costs 14 bytes; bit opcodes in place of the letters pay
for it twice over, since a letter costs a compare and a branch where a bit costs
a skip. Both guards go — the lock-bit refusal because the seal covers it, the
running-slot write guard because what it defended against was a wire fault
naming an address and a wire fault can no longer name one. That one is a real
trade: a host bug aimed at the running slot now lands. It buys a resident copy
that can write its own slot, which is the only self-update route on a chip whose
boot section *is* the slot.

Two things the tests caught, both introduced here. Removing the invalid-opcode
arm made every byte a command, so the knock stopped being harmless against a
loader already in session and ate the five bytes behind it — identify moves to
bit 5, which both 'p' and 'b' carry, so the knock is inert again and version
discovery still works before the version is known. And the SPM value rides the
count field because a data byte would arrive after the seal was checked.

pbselfwrite and pbglitch are the new gates, both red-green: the same erase of
the running page refused unsealed and performed sealed, and every header byte
damaged after sealing refused where the identical damage before sealing is
obeyed. Both judge by the simulator's flash, not the loader's opinion of it.
pbreloc and pbrehome lose their write-guard probes, which is what those two
gates replace. Defeating the seal in the loader turns seven tests red.

37 of 37 chips green with the exhaustive size matrix; README protocol section
and every size row rewritten. pbhw gains an adversarial --seal-rounds sweep for
the bench.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-08-01 18:38:41 +02:00
BlackMark
eb213e1025 one-wire: a lost echo and a dead line are not the same report 
The blind-write path said "lost to the device's ack" for any missing echo, and
the count is what distinguishes two different faults. Some bytes lost is the
device's ack winning the line against the host's series resistor — ordinary,
and what the knock retry absorbs. *Every* byte lost is nothing coming back at
all, which means the line is not free: a pin held low, a wedge, or an RX that
is not on it.

Found pointing the wrong way on purpose-built hardware. This rig's LED demo
ends by driving every port pin low, and one of them is the shared link — so a
knock into a finished demo got no echo whatsoever and was told the device had
acked, when nothing had answered and nothing could. Same retry either way, but
blaming an ack that never happened sends the reader to the protocol when the
answer is a pin.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-31 18:32:18 +02:00
BlackMark
3e4bfbaf48 pbhw: the marker check assumed a board whose port-open is not a reset 
Its comment said "opening the port does not reset a board whose DTR is
unwired, so this simply listens" — true of the tiny it was written against,
false of an Arduino, and this is the generic harness. Where DTR is wired to
reset, that open resets the part and the activation window comes first, so a
fixture emitting its banner once says it on the far side of a wait the suite
cannot know the length of: the window is a compile-time constant and nothing
on the wire reports it. The suite read the silence as an application that
never ran, on a board where it demonstrably had.

So --marker-wait, defaulting to the 2.5 s that was hardcoded, and a failure
that names the window as the candidate rather than leaving the next person to
suspect the loader. The other half is the fixture: PUREBOOT_HEARTBEAT makes
the observation independent of when the listener arrives, which is what the
rig's own builds now pass.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-31 17:12:08 +02:00
BlackMark
579ca81b27 one-wire: the knock's lost byte is the wiring, and the diagnosis was unreachable 
Measured on an ATtiny13A with the link folded onto PB3 and the FTDI's TX
reaching it through 1 k: a knock aimed at a loader already in session loses
its second byte every time, 8 runs of 8, never intermittently. The first byte
draws a prompt while the second is still going out and the device's push-pull
ack wins the line against the resistor, so that byte is destroyed rather than
delayed — which is what the README predicted and the sim bridge cannot show,
since it arbitrates the line by queueing.

The recovery for it existed and could not run. Two defects:

OneWirePort.write read its echo with read_exact, whose contract is to raise, so
the "one-wire echo missing — is the adapter's RX tied to the line?" message was
unreachable on any line that simply fell quiet, and a bare "timeout: got 0 of 1
bytes" surfaced in its place. The one message the class exists to produce could
never be produced. The read is speculative and is now read_available.

And any raise from write aborted _handshake before the retry loop that exists
to absorb exactly this, whose docstring already claimed it "converges into an
already-live session" — true on a pty, impossible on real wiring. The knock is
now the one write marked blind: a missing echo there is a property of the
shared line, counted and reported under -v rather than raised. Every other
write is ack-paced and cannot collide, so a missing echo there still means an
RX that is not on the line, and still raises.

Both gates green on Windows (31/31 m328p, 16/16 t13a); on hardware the
reconnect now converges on the first knock, the surviving prompt being all the
handshake needs.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-31 16:29:17 +02:00
BlackMark
5d520a1ff9 pbhw: --one-wire never reached the suite's own sessions 
The flag was plumbed through pbrig.Deployment to the host-tool subprocess
calls and nowhere else, so identity() and scan() opened a raw port and drove
a shared line as though it were two wires. On real one-wire hardware the
adapter's echo answers the knock before the device does, so the suite would
have died at its very first check — "the loader never answered; nothing below
can be trusted" — for the one deployment the flag exists to test, and every
result after it is gated on that check passing.

Both now open through pbrig.Rig.open_port(), which applies the deployment's
link mode. The gap underneath was that only the subprocess path could reach
those facts at all; anything driving the protocol in-process had to restate
them, and did not.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-31 13:25:46 +02:00
BlackMark
f71d76a815 pureboot v8: one-wire on every backend 
HALF_DUPLEX deploys a shared line per backend. The hardware USART takes
the library's .half_duplex turn-around — RXD and TXD tied off-chip, each
reply byte held to transmit-complete before the line can be released
(m8 404 B, m328P 440, 1284P 460; the window poll runs through the
outlined release-line call at 18 or 22 cycles a poll, measured off the
built loops and held per chip by pureboot.window.halfduplex). The
software and autobaud links fold onto the RX pin — RX == TX spells the
same — and cost nothing: the frame's direction wrap is what the dropped
second-pin init paid, and the worst image in the space is unchanged at
the 1284s' 502 of 512, now with its one-wire twin proven equal across
the exhaustive matrix. The host gains --one-wire, the echo discard a
shared line requires: the adapter's echo is matched byte for byte and a
reply interleaving a blind write — a loader already in session
re-prompts inside the knock — is held for the reader. The device runner
models the shared line by direction (drives only while the firmware's
DDR reads input, decodes only while the firmware owns it, supplies the
host-side echo), extends the USART pin-ownership model to RXEN's hold
on RXD, and starts the pty USART from the datasheet's zeroed UCSR#B:
simavr's TXEN-set reset plus its clear-UDRE-on-TXEN-drop otherwise
wedges the first transmitter after a receiver-only program, which the
half-duplex window gate caught as a banner that never came. v7 is
tagged at its era's last commit; v8 changes nothing on the wire.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-31 02:32:11 +02:00
BlackMark
47419400f6 build: the pin advances over the one-wire serial feature 
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-31 02:31:55 +02:00
BlackMark
bad8b6b43e build: the pin advances over the bounded calibration 
libavr's calibrate() now bounds its measurement loop, starts the pulse
on an observed edge, and re-arms a rejected pulse on the remaining
budget instead of one-strike booting the application. The autobaud
images pay +16..20 B — every slot still fits, the worst now the 1284s'
502 of 512 — and the stock images are byte-identical, kept so by
fitting the loader's flag set per backend: -fno-ivopts stays on the
fixed-baud bodies it shrinks and comes off the autobaud body, where it
duplicated the calibration countdown into a 9-cycle loop against the
contracted seven.

One deployed constant moved and its gate caught it: the calibrate
wait's budget poll re-laid from ten cycles to nine (the exit branches
land where block layout puts them), so pureboot.window.autobaud
measured -10 % until AUTOBAUD_POLL_CYCLES and the README's derived
seconds were re-measured — the default autobaud window is 36 M cycles,
4.5 s at 8 MHz. Full gate green on all 37 chips; the README's autobaud
column carries each chip's rebuilt worst configuration, machine-checked
against the built trees.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-30 22:49:55 +02:00
BlackMark
5d1b4497d4 build: the libavr pin advances over the drain and delay contracts 
The hand-over drains move to the explicit drain_unbounded() — both link
adapters drain only after their own write, so the frame is in flight by
construction and the bounded default's countdown would be dead bytes;
the images stay byte-identical. window_polls() states its arithmetic
through dev::cycles_for with the whole window converted before the
per-poll division — one truncation instead of one per second, same
instructions, only the countdown's immediate moves. Every size in the
matrix is unchanged; the full gate is green on all 37 chips.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-30 17:31:22 +02:00
BlackMark
a743ea64a3 tool: a size collision across build trees is an error, not a coin toss 
sizes.py merged every owned tree's rows and let the last one win, so a
stale reflect tree — last built before the window constants moved —
reported the atmega8's old stock size over the fresh build and failed
the README check with yesterday's number. Generated and reflect must
answer with the same bytes (the identity invariant), so the same target
measuring two sizes is a stale tree or an identity breach; collect()
refuses now, naming both trees. The stale reflect trees are removed —
the reflect sweep rebuilds them.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-30 16:32:35 +02:00
BlackMark
aa66cfccff pureboot: the poll-cost lookup rides the baud parameter 
usart_of<0> is an incomplete type on the USART-less chips, and a static
member initializer with only non-dependent operands is checked when the
template is parsed, not when it is instantiated — so the address probe
broke every tiny build without hardware_link ever being named. The
lookup moves into a member function template taking the link's own baud
parameter, the dependence carrier that defers it to instantiation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-30 16:13:44 +02:00
BlackMark
459d463283 pureboot: the classic megas' idle poll is a bit-skip — 7 cycles, and their stock window goes wide 
The window gate's first full sweep caught it on the atmega8: 6.22 s
measured against 8 declared, the exact 7/9 of a poll modeled as an
extended-I/O lds + skip on a chip whose UCSRA sits in bit-addressable
I/O and compiles to a 2-cycle skip. poll_cycles now follows the status
register's home (7 below 0x40, 9 above). At 16 MHz over 7 cycles the
poll count no longer fits uint24_t, so the classic megas' stock windows
take the wide countdown — 8.000 s measured on all three, +4 B of stock
image (m8 362, m16/m32 364), README stock rows updated.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-30 16:11:34 +02:00
BlackMark
8e7cc86fb3 pureboot: the activation window gets a behavioral gate, and honest per-poll constants under it 
The window's per-poll cycle counts were hand-counted for a uint32_t
countdown, but every default window fits uint24_t, whose decrement chain
is one sbci shorter — so deployed loaders ran 9/10ths of their stated
seconds (a 328P's 8 s was 7.2 s on the wire). No golden-asm pin can hold
this: the loops compile in consumer context. pbwindow.py measures the
behavior instead: it installs a real application beside the loader
through the host tool's own plan_flash (surgery included), starts the
simulator with the line idle, and reads the cycle of the first transmit
— the application's banner, so that cycle is the window. Held at plus or
minus 2 percent per chip (pureboot.window), red at -10.0 percent against
the old constants, green with poll_cycles now counted for the narrow
countdown (hardware 9, software 7; window_polls() solves narrow-first
and adds the wide loop's cycle where the count forces uint32_t — a count
narrow only at the wide cost stays wide, so the choice cannot
oscillate). The autobaud window is its poll budget at the measured ten
cycles a poll, gated the same way (pureboot.window.autobaud), and the
README carries that arithmetic now. No version bump: timing-window
precision is not meaningful behavior, v7 stays.

The gate flushed out two runner gaps. The software bridge accepted any
falling edge as a start bit, so the device's own TX-init glitch decoded
as a stray byte; it re-samples mid-bit now and abandons a false start,
as silicon does. And after avr_reset, the idle-line re-raise was
silently dropped: ioport pin irqs are IRQ_FLAG_FILTERED and the irq's
cached value survives the reset the port latch does not, so the device
read the line stuck low, calibrate() measured reset-to-first-edge as one
wrapping pulse, and the first knock after a reset could boot the
application instead of locking — the intermittent autobaud failure.
bridge_reset forces a real transition (0 then 1, no cycles between).

The README's Autobaud column now carries each chip's worst
configuration — autobaud with OSCCAL baked, on a USART's own pins where
the chip has one (tinies: autobaud + OSCCAL) — the numbers the existing
pureboot_autobaud_osccal[_on_usart0] matrix points already gate;
sizes.py checks the column against exactly those targets. Tool sizes
and window prose updated with it.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-30 16:05:42 +02:00
BlackMark
c8ac61779e tool: survive our own leftovers — drain the fresh port, shorten the identity read 
--stay leaves the loader's final prompt in the USB pipeline; a fresh
invocation on a board that resets when its port opens then flushes too
early, trusts the stale prompt, and spends the new activation window on
a 2-second identity read against a device that never heard its knock —
collecting the application's banner as an unknown signature. Three
host-side moves, no device bytes: the line is drained until quiet
(bounded, 250 ms) before the port's first knock — once per port, since a
mid-session re-knock faces no foreign bytes and its own window is
already burning; the identity read_exact drops 2.0 to 0.5 s, dozens of
times the worst real answer, so any false prompt match leaves room for
the retry that already works; and the tool version drifts to 8. The
StaleDTRPort fixture models the whole moment — stale prompt in transit,
reset holding the device off the line, a finite window, the banner —
red against the old tool in exactly the field shape (unknown signature
from banner bytes), green now; LoaderPort answers its prompt to the
knock rather than to a read count, which the drain exposed as a
call-order coupling.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-30 16:05:16 +02:00
BlackMark
4362886c39 build: the libavr pin advances over the trait projection 
The de-string-2 pass upstream: every peripheral block behind generated
instance traits, int-keyed, the string layer gone. The port's share of it
is two spellings — the char usart_digit that existed to be pasted into
register names becomes the int unit the usart template now takes, and the
tsb tiers' one reg<"UBRR0"> is the flat hw::ubrr0 — plus the pbapp
harness probing has_usart<0>() instead of instance-name strings. Nine
loader codegen families rebuilt green through their full workflows (size
matrix and simulator protocol suites included); every image holds its
recorded size.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-29 20:08:10 +02:00
BlackMark
0513d07e87 build: the libavr pin advances to current main 
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-29 07:24:10 +02:00
BlackMark
d4ab28aa17 build: the libavr pin advances to current main 
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-29 06:48:37 +02:00
BlackMark
b60f182105 review: the port's findings — the version map speaks v7, costs told true 
The in-file version window now carries the v7 line its own comment
claimed to hold; the GPIOR note counts words, not instructions; the
USART-release cost and citation match the silicon (two bytes on the
classics, §20.6.3); and the 512-byte claim reads as the slot bound it
is. The libavr pin advances over the review pass — images byte-identical.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 20:05:42 +02:00
BlackMark
5bc35a9733 build: the libavr pin advances over the instance traits 
Byte-identical images — the traits resolve the same database indices the
retired string forms did; the tightest image is compared outright.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 17:18:07 +02:00
BlackMark
8f6319c068 pureboot 7: the same features in fewer words on every chip 
Four cuts, none touching what the loader can do. The entry stub stops
re-doing the reset logic's own SP write where the datasheet guarantees
RAMEND (stack::hardware — the classic megas keep theirs). The autobaud
unit moves into GPIOR2:GPIOR1 wherever the chip has the pair: one-word
accesses, no RAM object, and the host's measured-clock peek follows it
by version and geometry. 'J' rides the unified decode, carrying a
selector it ignores so its address is the same two reads as every other
command — the tool sends the bare form to older residents. run_app stops
insisting on a body of its own. The fleet lands at 358–410 B stock and
438–474 B autobaud; the tightest image in the space — the 1284s'
autobaud on a USART's own pins with the OSCCAL trim — drops from 510 to
484 of its 512. Every chip's suite is green on the wire that changed,
and the README's table is machine-checked against the built images.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 17:02:38 +02:00
BlackMark
a3ea099105 pureboot: the detail reaches become the library's own API 
The three things this repo took from under libavr's counter are now over
it, and the local copies fold away. The USART release on a software
link's pins is the library's init contract (its guard here becomes a
deletion, byte-identical images held by the gate); the WDRF routing test
is power::peek_reset_cause().watchdog instead of a hand lookup of the
flag's register; the tsb tiers' baud arithmetic is the public solver.
libavr pin advances over those three additions.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 16:12:35 +02:00
BlackMark
c535c4756c pureboot: the activation countdown in the narrowest type that holds it 
The fixed-baud window counted down a uint32 where almost every window fits
24 bits; the countdown now takes avr::uint24_t when the poll budget allows
(the autobaud budget's own choice), uint32 past 16.7M polls — four bytes
off every fixed-baud image on every chip, the full suites green on the
changed window. The README size table is refreshed — its autobaud column
had also gone stale by the no-assembly pass's measurement-loop win, which
nothing gated: sizes.py check-readme now runs as the gate's final stage,
where every tree is freshly built and the table can actually be held.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 14:47:29 +02:00
BlackMark
321ff8a4ee test: the device runners speak the C++ the rest of the repo does 
pureboot_device and the tsb device, C until now, rewritten in C++23 with
every modeled behavior intact — the PGERS Z-mask and m48-discard ioctl
wraps, the GPIO bridge's timing and pacing, the tiny NVM's write-once
buffer, pin ownership, and the PB_PTY/TSB_PTY lines the harnesses parse.
The one linkage fact worth a comment: simavr's parts headers (uart_pty.h)
carry no C++ guards where its core headers do, so those includes sit in an
extern "C" block. Warning-clean at -Wall -Wextra on the build line; the
full protocol suites on all four sim-driven chips prove the conversion.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 13:59:03 +02:00
BlackMark
531ae6c8dc build: the libavr pin advances over the audit rounds 
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 10:52:05 +02:00
BlackMark
b3f41caf6e audit: round three on the port — the hardware scan check fails soft 
A rig hiccup mid-walk records the scan check as failed and lets the suite
continue, matching its siblings' envelope; a nonexistent --port path
reports as an error instead of a traceback.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 10:31:32 +02:00
BlackMark
7716e1e291 audit: the port's pass — the scan that could not walk, and the drift a generator ends 
--scan's walk was unwalkable on POSIX: probe rates have no termios
B-constant, so the first off-nominal probe raised out of the loop. The port
speaks termios2 BOTHER now (red-proven on a pty at 9984 Bd), the probe's
open lives inside the walk's error handling, an fd no longer leaks on an
unmakeable rate, and the swallowed unknown-signature reply is named at
timeout instead of reported as silence. CMakePresets.json's generator emits
the submodule toolchain path it had drifted from — a hand edit on a
generated file, exactly the class rule 10 exists for — and presets.generated
gates the pair from here on (the  marker CMake rejects at the
presets root stayed out; the check is the guard). The over-slot image guard
the tsb runner gained reaches the pureboot runner too; the GPIO bridge's
delivery comment states the hardware truth (RXC at the stop bit's sampling
point); the hardware suite gains the scan check — the one place the rate
physics is real; and the libavr pin advances over both audit rounds.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 10:12:17 +02:00
BlackMark
1b18f10f4e docs: the OSCCAL axis, --scan, and the RC-oscillator deployment risk 
Configuration gains the OSCCAL row; Deployment says what the build cannot
see (±10 % factory trim against a frame's ~±4 %, and silence that reads as
wiring); the update section names an OSCCAL bake as a link change in effect,
declared with --staged-baud; the host-tool section documents --scan and the
measured clock --info adds on an autobaud session; the version map gains 6.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 01:03:15 +02:00
BlackMark
52c4cdab32 pureboot.py: --scan walks a silent loader's rate; --info decodes the clock 
The RC-oscillator answer's host half. --scan probes ±10 % around the built
rate in 2 % steps, nearest first, one activation window (one reset) per
probe: a fixed-baud loader whose oscillator drifted answers at the ratio,
and the report gives the session workaround (--baud), the offset, the
OSCCAL direction at ~1 %/step, and the autobaud way out. The walk and the
advice are logic-tested (test_scan.py, red-proven on the trim direction) —
a pty carries bytes at any rate, so the wire cannot arbitrate them.

On an autobaud session --info now reads the measured bit period from
ram_start — the geometry table gains that column — and undoes the unit's
encoding ((cycles − 8) / 4, floored: libavr's spin granule and per-bit
overhead), so the printed clock is the true one within a granule; --clock
turns it into a stated drift. The autobaud end-to-end asserts the figure
inside exactly that envelope at both clock points.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 01:01:35 +02:00
BlackMark
69f089e53a pureboot 6: a build-time OSCCAL trim, applied ahead of every reset path 
The RC-oscillator answer's device half (dev/tasks.md in libavr): OSCCAL joins
pureboot_add_loader() as one optional byte, written at the top of run() before
the WDRF bail so the watchdog hand-over inherits the corrected clock too.
Orthogonal to the backend — an autobaud build may carry it purely for the
application. No value, no code: the stock image differs from v5 in exactly
the version's two bytes (the stamp and the 'b' immediate).

Measured: +6 B where OSCCAL takes sts (328P, 404→410), +4 B in low I/O
(t85, 402→406); the tightest image in the space (1284 autobaud on USART
pins, 504) carries the sts form at 510 of 512. New gates: the OSCCAL size
points on every chip, the wire-observed trim byte on both addressing
classes (test/pbosccal.py, red-green), and the autobaud unit pinned to
ram_start (test/check_unit.cmake, red-green) — the address --info's
measured-clock read is about to rely on.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 00:53:14 +02:00
BlackMark
fe0d9f8790 build: the submodule is how libavr arrives; the era already carries it 
The pin the whole history now encodes becomes the primary route: the
submodule default replaces FetchContent and the unpinned forge fallback,
LIBAVR_ROOT stays as the tandem-development override, the presets already
take the toolchain file from the submodule, and the Studio projects anchor
their include path there — correct by construction. The version tags and
the one-command historical build are documented beside the version map.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-28 00:28:49 +02:00
BlackMark
3ce817ea03 ide: the Atmel Studio solution master has, on the libavr port 
master carries bootloader.atsln, so main does too. Two projects, because a
.cppproj is one binary at one flag set and this build has hundreds: the stock
328P pureboot loader (USART0 at 115200 on a 16 MHz crystal), and the tsb_asm
tier that occupies the same 512-byte section master's own tsb project targeted.
Both come out byte-identical to the Ninja build — 404 B and 510 B of .text —
in both configurations.

Debug keeps -Os and adds only -gdwarf-4. A loader's section is a correctness
bound, and -Og builds this source to 590 B: the link at 0x7e00 accepts that
without a diagnostic, 78 bytes past flash end, where rcall/rjmp wrap modulo
flash size and the image dies just after activation. Debug info costs no flash,
so the optimisation level stays where correctness needs it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-27 22:15:28 +02:00
BlackMark
af0dd15a77 tsb: the policy floor, measured and kept 
A fourth tier answering one question: what does the full TinySafeBoot
feature set cost in C++ under pureboot's rules — no assembly, no
register variables, every pureboot lesson applied. 638 bytes, protocol
suite green: 198 below the idiomatic tier, 126 above the 512 B section,
and above the tiers that pay with the banned mechanisms (526 global
registers, 510 with two asm routines). The gap decomposes into the rent
policy-clean C++ pays for state held across calls — push/pop and
argument threading a global-register protocol avoids — and both
control-flow merges tried measured larger than the split cases they
replaced, while the data merge (one send loop over both memories) paid.
The tiers stay; this one keeps the floor an artifact instead of a claim.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-27 18:57:13 +02:00
BlackMark
a54075e526 test: the device runner refuses an image that runs past flash end 
A boot-linked image larger than its slot cannot execute on hardware, and
the naive copy smashed the heap beyond avr->flash — after which the
simulation misbehaved in ways that pointed everywhere but at the size:
phantom byte losses on the UART, garbage in SPMCSR, all downstream of
the overrun. The size gate had said it plainly; now the runner does too.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-27 18:57:13 +02:00
BlackMark
aec430c2e1 docs: name the two data-space regions a poke cannot survive 
Writing 0x60-0x61 on an ATtiny13A reliably garbled the link, which looked like a
loader defect. It is the loader's own footing: .noinit lands at exactly 0x60,
size 2, and on an autobaud build that is unit_ — the measured bit period, and the
whole of its static RAM. Overwrite it and the next reply is timed against
garbage, so the symptom is a mangled prompt byte and no error, because nothing
went wrong except the rate both ends had agreed on.

Identical in kind to poking the stack at the top of SRAM, and cleared by a reset.
test/pbautobaud.py already steered its RAM round-trip clear of the bottom of SRAM
for this reason; only the README had not said it. Both regions are named there
now, beside the note that --poke does reach OSCCAL but that a session survives
only a step or two of moving the clock under itself.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-27 16:48:09 +02:00
BlackMark
9a8a5b0082 tools: measure the images, and hold the README to what is built 
The size matrix proves every image fits its slot and says nothing about the
numbers the README prints. Those drift silently: caller_page() took eight bytes
off every build at once, so all fifteen rows went stale together and no test
noticed, because nothing was over budget. sizes.py check-readme compares the
table against the built images; sizes.py max reports the largest image per chip
and anything over its slot.

It is a check rather than a generator, so the table stays prose someone can
write. No chip geometry lives here either: the image/budget pairs come out of
each build's own CTestTestfile.cmake, which is what the gate checks, so a chip
added or a budget changed needs no edit. Only trees a preset still owns are
read — a stale directory answers with a size that was true once.

16243 images across 37 chips today, none over budget, tightest tsb_asm at 510
of 512.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-27 16:45:20 +02:00
BlackMark
7702c6b700 test: gate autobaud's logic floor, and say what an RC oscillator costs 
The ATtiny13A run left autobaud's low-clock lock looking unreliable: 1/5 at
19200 on a 1.2 MHz RC part. The simulator does not reproduce it. At an exact
clock the calibration is solid down to ~36 cycles a bit and fails outright by
~31 — a sharp edge, not a fraying one — where the real part was already 1 in 5
by ~59. So the effect is the oscillator's own jitter and not backend logic, and
the two floors are different quantities about a factor of two apart.

Both are worth having. pureboot.autobaud gates a tight-bit point, since its two
existing clock points both sat near 100 cycles a bit and would not notice the
floor moving. The README carries the other half: both floors side by side, the
per-clock envelope measured on silicon, and the reason budgeting the logic's ~36
on an RC part is wrong.

It also carries the trap that produced the confusion. On a patched-vector chip an
erased application region walks back up into the loader, so every expired window
opens another and the host's retries eventually catch the pulse — 5/5 where the
same part with an application resident gives 1/5. Measure with an application in
place, or the fixture flatters the backend.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-27 16:44:21 +02:00
BlackMark
77dd45aeca pureboot.py: an update follows the staging copy onto its own link 
--update-loader works by entering copies of the *new* image and letting them
rewrite the resident. Those copies speak the link they were built for, but the
host went on knocking with the session's baud and backend — the resident's. Where
the image changed either, the staging copy was installed and then never answered:
resident untouched, and on a 1 KiB tiny the staging slot is the whole application
region, so the application was already gone.

The wire cannot be probed for it. 512 bytes of position-independent code carry no
header saying what rate they were built for, so the operator declares it:
--staged-baud and --staged-autobaud, applied from the jump into the staging copy
onward. Retuning goes through the open port — SetCommState or tcsetattr on the
live handle, never a reopen — because a DTR pulse would reset the copy being
talked to. Undeclared against a changed link it still cannot work, but the error
now names that as the cause instead of reporting the bare activation timeout that
sent the operator looking at wiring.

The README's idempotence claim needed the same qualification: from step 2 a
re-run must reach the new image, and after step 3 word 0 points at the staging
copy, so on a patched-vector part the resident's link reaches nothing at all.

Found on an ATtiny13A, where two controls differing only in the activation window
updated cleanly and so isolated the link as the variable.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-27 16:31:27 +02:00
BlackMark
433bec3e58 tools: a hardware harness, so a board can be proven and not just a protocol 
check.sh proves the protocol under simavr on every chip; it cannot prove a
board. Two things live only on silicon — an RC oscillator that is not on its
nominal, and a reset edge that has to come from somewhere — and until now the
scripts that reached them were per-session scratch on the machine holding the
programmer, which is where the ATtiny13A run's findings nearly stayed.

pbrig.py is the primitives, knowing nothing per-board: every deployment fact is
a flag or a PUREBOOT_* variable. Two rig facts are encoded in it because neither
is guessable and each cost a session to learn: an ISP access *is* the reset edge
where the adapter's DTR is unwired, so a session begins with an ISP touch and
knocks immediately after; and avrdude splits -U on colons, so a Windows drive
letter breaks the spec and every file goes as a bare name with avrdude run in
its own directory. Its `rate` subcommand is the one that turns "the loader is
silent, so the wiring must be wrong" into a number, by sweeping the host rate
against a fixed cycles-per-bit transmitter — PUREBOOT_HEARTBEAT makes the
existing fixture into one, software link only, since the hardware-link idle owes
the self-update tests its command loop.

pbhw.py takes every bound from the info block the loader reports, so one run
covers a 1 KiB tiny and a 128 KiB mega alike. Both are exercised on an ATtiny13A:
backup verified against a known-good capture, the clock measured at 9.048 MHz
against a 9.6 MHz nominal, and the suite 11/11.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-27 16:06:15 +02:00
BlackMark
e89000f73e pureboot: the pin axis, and the mute it was hiding 
Pins move the image for exactly one reason — a bit-banged link on a USART's own
pins has to release that USART — and the matrix said outright that they were no
axis, so the tightest configuration in the space was one nothing built. Not
subtly, either: the 1284's slot ends at flash end, so that build does not merely
exceed the size test's limit, it fails to link. pureboot_{sw,autobaud}_on_usart
{0,1} are gate points in both matrix modes now, and the exhaustive sweep carries
the pins across its whole cross product. The hand-measured table is the gate's
output: 506 B of 512 for the 1284 autobaud on USART0's pins, 504 on USART1's.

pureboot.mute drives the defect itself — an application hands over with USART0
still enabled and the loader on those pins must still answer. Reaching that
needed the runner to know an enabled USART owns its TxD, which simavr does not
model at all: it wires a USART through IRQs and never takes the pin from the
port. It also brings UCSRnB up with TXEN already set where silicon clears the
register, so the runner restores the reset value for the USART it models — the
mute must come from the application, not from power-on. The fixture stays
silent, since nothing is listening on the USART it brings up.

test_handshake.py, written where no gate could run it, is pureboot.handshake.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
 2026-07-24 22:08:56 +02:00
BlackMark
b0737f7cc0 test: move the handshake regression in beside the rest 
It was written next to the loader source; the harness lives at the repo root.
Not registered with ctest yet — it belongs beside pureboot.planner, which is
the other test of the host tool's pure logic.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-24 18:22:19 +02:00
BlackMark
07f93caba8 pureboot: take the running slot from avr::startup::caller_page 
The write guard's anchor was costing a materialised pointer and a byte swap to
use one byte of it. The libavr primitive answers it in a single load, which is
eight bytes off every build — and what lets the USART release fit the tightest
configuration in the space: the 1284 autobaud on USART-shared pins was 514 of
its 512 and is now 506, with the default pinning down from 510 to 502.

Verified on silicon: the guard still refuses an erase aimed at the slot it runs
from, and still permits one in the application region.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-24 17:57:47 +02:00
BlackMark
45f10f843a pureboot: release a USART left enabled on the software link's pins 
A software or autobaud link on a USART's own pins (PD0/PD1 on the mega328P, so
the Uno's USB bridge reaches it) was mute after an application handed over with
that USART still enabled: its TXEN keeps the USART owning the TX pin, so the
bit-banged transmitter cannot drive it — the loader locked and obeyed commands
but never answered. The link's init now clears the UCSRnB of the USART whose
TXD is its TX pin. Guarded with if constexpr on that pin match, so a link on
non-USART pins emits nothing: +4 bytes on a USART-pin build (494 of 512 for the
mega328P autobaud), zero on the default pb0/pb1 matrix.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-24 17:22:48 +02:00
BlackMark
34b47048ca pureboot.py: bump the tool version to 5 
The drain fix changes the tool's activation behaviour; mark it. The loader
version window is unchanged — the wire protocol did not move.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-24 17:11:03 +02:00
BlackMark
392035923f pureboot.py: bound the activation drain against a flooding target 
The post-prompt settle loop in _handshake had no deadline, so a target that
never falls quiet — a board stuck in a reset loop, whose UART-reset garbage
carries a stray prompt byte — spun the tool forever. Bound it by the handshake
deadline; a real loader still settles on its first quiet read. Regression:
test/test_handshake.py (flood terminates, valid loader still connects).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-24 17:10:40 +02:00
BlackMark
f98ed406b8 pureboot 5: one command pair for every memory, and a clock-free backend 
R/r/w/F collapse into G and g over a selector byte naming the space — flash,
EEPROM, data, fuse, SPM — with the flash bank in its high nibble. Four command
bodies, four transfer loops and four argument decodes become one of each, and
W joins the same decode instead of keeping an address form of its own. The
loader shrinks while gaining everything below: on the 1284P the stock build
goes 480 -> 432 B and the software one 496 -> 450.

What the freed space buys:

  - Data space. On AVR one pointer spans SRAM, the register file and the whole
    I/O space, so G over space 2 reads all three. pureboot keeps zero static
    RAM and pushes no register, so at loader entry an application's SRAM is
    still what the application left there — this is a post-mortem, not just a
    poke hole. As its own command it needed a dispatch arm and a loop; as one
    more space it is a single ld/st.
  - Host-issued SPM. W fills the page buffer and stops; erase, write and RWW
    re-enable are writes to space 4, which reach the same fused store-and-SPM
    pair through the transfer's own address and data. Any SPM operation, lock
    bits included, is now reachable and the loader carries no page-commit logic.
    The four-cycle SPMCSR-to-SPM window is why that primitive stays fused: no
    host can hit it across a serial link, and that — not the byte count — is
    the floor on how low-level a bootloader's primitives can go.
  - Byte addresses everywhere. The bank in the selector retires the
    word-addressed wire the >64 KiB parts needed, so the 1284s stop being the
    outlier.

SERIAL autobaud is a third backend on the same loader, over libavr's
software_autobaud: no clock, no baud, one binary per chip for every F_CPU and
every rate. Activation counts poll iterations rather than seconds and bounds
every wait, so a stray pulse cannot hold an unattended device.

b answers with the version and signature only; the host derives geometry from
the signature, which is what an autobaud build requires anyway. An update image
is a bare slot with no device to ask, so every image carries a six-byte stamp —
the same bytes b answers with, and the source of both — that the loader never
reads from flash and the host refuses to install a mismatch against. The
running-slot write guard moved onto the SPM commit, which covers erase and
write both where guarding W covered neither directly.

The position-independence lint now proves the property instead of a proxy for
it: the image must come out byte-identical linked at a different base.
-fno-move-loop-invariants left the tuned flag set — it was fitted to a command
loop carrying four transfer bodies and costs bytes now that it carries one.

Verified: the exhaustive matrix on all 37 chips (every clock x every baud x
every backend, non-standard rates included, plus the autobaud build) —
8174 size checks, no failures, tightest fit the 1284s' autobaud at 510 of 512.
Behavioral suites green on every chip class: t13a 10/10, t85 11/11, m8 13/13,
m16a 13/13, m48pa 13/13, 328P 23/23, 644A 17/17, 1284P 17/17. Data-space
round trip through --peek/--poke and the autobaud handshake are both red-green
proven.

The two prototype sources and their findings file go; the README carries the
protocol and dev/done.md in libavr carries the reasoning.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-24 15:50:48 +02:00
BlackMark
a4da885e36 pureboot: the unified autobaud loader, and the hang that settled the decision 
Hardware testing found that a lone calibration pulse wedged the autobaud loader:
run() budgeted only the start-edge wait in measure(), and the rx() that read the
knock behind it was unbudgeted, so one stray low pulse held an unattended device
in the loader and the application never ran. Bound the whole activation — an
expired knock budget returns a byte that cannot be the knock, so control falls
back into the budgeted measure() and an idle line boots the app there.

That fix costs ~22 B, which neither version under review could absorb: the pure
one goes 508 -> 530 on the 1284P and the register one 512 -> 534, both over a
512 B slot. Their margin was never spare capacity, it was the space the missing
fix should have occupied. So the choice between them is moot; both are kept for
the record and no longer built.

pureboot_autobaud_uni.cpp replaces them at 464 B. It is pureboot 5: one read
command and one write command over named spaces (G/g, sel8, addr16, n8) instead
of four per-memory bodies, which collapses four transfer loops into one. The
selector's high nibble carries flash's bank, so the shared cursor stays 16 bits
and no command speaks word addresses. Three things fall out of the freed space:
RAM read/write — the missing feature, and with it arbitrary I/O access, since
AVR maps peripherals into the data space; host-issued SPM, so W's hardcoded
erase/write/RWW tail becomes three writes to a space and any SPM operation is
reachable; and W on the same selector-and-address decode as everything else.

Strictly pure throughout: no inline asm, no global register variable, and no
GPIOR either — the unit lives in a .noinit static, so the loader claims no chip
resource and the chips without GPIOR stop being a special case.

pureboot.py speaks both generations, keyed on the version, so the fixed-baud
path is untouched; --peek/--poke reach the new data space. pbautobaud.py adds a
RAM round-trip and a regression for the hang: a lone pulse must still let the
app boot. All 37 chips plus the 12-preset reflect spot set build and size-test
green, 444-466 B, worst case 46 B under budget. Sim suites 100%: 1284P 17/17,
328P 23/23. Only real-hardware acceptance remains (pureboot/autobaud.md).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-24 00:48:54 +02:00
BlackMark
335e494a31 pureboot: autobaud host support and simavr end-to-end for both variants 
pureboot.py --autobaud sends the 0xC0 calibration pulse and a single knock at
the host's chosen baud, reads the slimmed info block, and derives the full
geometry from the signature (AUTOBAUD_GEOMETRY, a table over every pureboot
chip). Everything downstream — flash, EEPROM, fuses, hand-over, verify — is the
fixed-baud path unchanged; the dropped write guard is host-transparent.

test/pbautobaud.py drives each variant over the GPIO⇄pty software-UART bridge
through the calibration handshake and a flash + EEPROM + fuse round-trip
cross-checked against the simulator's ground-truth memory, then repeats at
double the F_CPU with the same binary — the clock-agnostic property autobaud
exists for. Wired as pureboot.autobaud_pure/reg on the near-flash 328P and the
word-addressed 1284P. A wrong measured unit fails the flash/verify, so the test
also pins the codegen-coupled calibration constant against a toolchain bump.

Both variants green in sim on both chips at two clocks each; the fixed-baud
suite is unaffected. Only real-hardware acceptance on an RC part remains
(pureboot/autobaud.md).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-23 22:45:22 +02:00
BlackMark
799709efcf pureboot: autobaud variant, two versions for review 
Measure the host's bit timing at runtime from a 0xC0 calibration pulse, so one
clock-agnostic image per chip runs at any F_CPU — the RC-oscillator deployments
no longer need a per-clock build.

Two source files, differing only in the write-guard/purity tradeoff:
pureboot_autobaud_pure.cpp (the measured unit in the GPIOR I/O scratch
registers, running-slot write guard dropped, 508 B on the 1284) stays strictly
pure; pureboot_autobaud_reg.cpp (unit in one global register variable, guard
kept, 512 B) keeps every feature at the cost of that single GRV. Both fit
512/510 on all 37 chips and share two licensed simplifications: a slimmed info
block (version + signature; the host derives geometry from the chip database)
and a single-byte activation knock.

pureboot/autobaud.md records the decision, the hand-assembly floor (506 B) that
set the target, and the compiler-knob path to it. Size-tested on every chip via
pureboot_add_autobaud(); the fixed-baud loader is untouched. Sim validation, the
host calibration handshake, and real-hardware acceptance remain.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-23 22:15:38 +02:00
BlackMark
7ae80087b3 docs: the watchdog-lockout and EEPROM-wrap gotchas 
A sticky WDRF diverts every reset past the activation window (deliberate, so
an app can reboot instantly, at the cost of a possible lockout); an EEPROM
address past E2END wraps onto low EEPROM (the host bounds it, not the loader).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-23 02:01:33 +02:00
BlackMark
b477f53ca5 pureboot: the info block reads as a table, one wire byte per line 
clang-format bin-packs braced lists to the column limit, collapsing the
'b' reply's byte layout into dense rows. A minimal clang-format-off span
keeps each wire byte on its own line, where the layout is legible against
the protocol. Whitespace only; image byte-identical.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-23 01:19:09 +02:00
BlackMark
84d3f679c2 style: clang-format the W-fix line 
Layout only, byte-identical output.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-23 01:13:51 +02:00
BlackMark
b5020a1e20 pureboot 4: the loader carries its fixes' identity 
The unaligned-W and U2X-hand-over fixes change the loader's observable
on-wire behavior, and the --stay reconnect fix changes the host tool, so
both move: loader version 3 -> 4, tool VERSION 2 -> 3. The protocol and info
block are unchanged, so OLDEST_LOADER stays 1.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-23 01:09:38 +02:00
BlackMark
1dbf0089d6 pureboot: the info block is what proves a knock landed 
A prompt byte alone does not: one left over from a previous session can
still be in the pipeline while the port opening resets the device into a
fresh window, where the bare command that follows is discarded. Each
attempt is now the whole handshake, retried until the block comes back.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-22 23:49:37 +02:00
BlackMark
39dfe40dbf pureboot: W addresses a page, not a word in it 
The in-page bits of a W address are dropped so the fill always walks from
the page base; the wire contract is one page of data for any address
inside it, on both the byte- and the word-addressed path. +2 B.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-22 23:43:41 +02:00
BlackMark
8470ce3da0 test: the exhaustive clock x baud x backend size matrix 
Every plausible oscillator against every rate it reaches against every
backend, on one chip per size-bearing class, under --full only. The baud
ladder becomes a reachability predicate the enumeration filters on, so an
unreachable point drops out instead of aborting the configure.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-22 23:32:28 +02:00
BlackMark
d634741015 pureboot 3: a 512-byte slot on every chip, the 1284s included 
The word-addressed 1284s were the one family deploying in a 1 KiB slot,
because the far-flash machinery (ELPM reads, RAMPZ page commands, a
word-addressed wire) did not fit 512 B. It does now: 478 B stock, 494 B in
the heaviest configuration the build can produce. They take the 644s'
geometry, where the smallest boot section holds the resident slot and its
staging slot together. The loader's version goes to 3; the host tool did
not change, so its own version stays 2 and only the window it speaks
widens.

Most of the saving is one restructure. The info block and a flash read are
the same act, so giving all four streamed commands one address-and-count
path leaves exactly one call site for the flash streamer: it inlines into
the never-returning command loop and its 24-bit cursor stops being saved
and restored around every transmit. Around it, the ack byte moved out of
line, the wire's byte pair is bit_cast into the word it already is, the
fuse loop ends on its count, the info block's in-slot offset is taken as
the one-byte relocation it is, and -fno-expensive-optimizations gives way
to -fno-move-loop-invariants -fno-tree-ter. Every chip shrank 14-18 B.

The size matrix grew the axes it was missing: the USART1 instance across
the whole clock ladder, and the shape a slow baud gives a software UART —
past 255 delay iterations libavr takes the 16-bit delay loop, which the
ladder default never selects and which was 4 B over the 1284's slot the
first time it was built.

The protocol fixture stopped deriving the loader entry from the flash
size; on the 1284s it had been jumping a slot low and reaching the loader
only because erased flash walked it up.

Docs and comments were consolidated across the port in the same pass: the
README carries a per-chip size table instead of prose, and prose that
restated the code is gone — 190 lines, no behaviour with it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-22 20:49:23 +02:00
BlackMark
ab842c8d99 pureboot: a version number for the loader, not for the protocol 
The info block's third byte was a protocol version that never moved in the
loader's lifetime. It is the pureboot version now, and this change is
version 2: the one number that says what a deployed loader is. Every loader
already in the field answers 1.

The protocol keeps no number of its own — a pureboot version implies it, and
the host tool is what holds that map. pureboot.py states the loader-version
window it speaks (OLDEST_LOADER/NEWEST_LOADER; a version that changes the
protocol becomes the new floor there), so a loader newer than the tool is
refused by name rather than decoded on the assumption nothing moved, while an
older one is read, identified and installed like any other. The tool carries
its own version, free to drift from the loader's: --version prints it and the
window, --info leads with the device's, --update-loader names the version it
installs.

Tests: the planner unit pins the window — every version in it decodes, one
above it is refused, an older loader's image is still found — and the live
suite pins the built loader against the tool beside it, so a bump that reaches
only one of them fails. The image is byte-identical to the previous build but
for that byte.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-22 17:20:34 +02:00
BlackMark
a58b59c60f docs: correct the size figures for the configured variants 
The headline numbers described the stock deployments but claimed "every
configured variant of them", which the matrix contradicts: choosing the
software UART where the chip has a USART costs 8-46 B, so the megas reach
460-462 rather than 452, and the 1284s' software-serial build is 546 B —
inside their 1 KiB boot sector, but not inside 512.

Also names the actual tightest chip. The 1284 looks like it at 506, but it
deploys in 1 KiB with 478 B spare; against its own budget the ATmega328P
has the least room, 50 B.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-22 17:08:24 +02:00
BlackMark
ceacb61ba1 pureboot: no SPM buffer discard, the host repairs instead 
The temporary page buffer is write-once per word, so a page filled over
one an earlier writer left dirty programs the stale words. The same
datasheet clause carries the cure: the buffer auto-erases after a page
write (§26.2.1; §19.2 on the tinies), so the corruption clears itself by
happening, and rewriting the page programs correctly.

The loader therefore clears the buffer nowhere. The tinies' CTPB and the
m48s' RWWSRE discard are gone; the boot-sectioned megas keep only the
trailing RWWSRE they need anyway to re-enable the RWW section for
read-back, which discards the buffer as a side effect and keeps them off
the path entirely. 434 B on the tiny13s, 438-442 on the tiny25/45/85,
430 on the m48s; the megas are unchanged, the 1284s still 506.

The host takes over the guarantee: a flash page that reads back wrong is
rewritten up to RETRIES times before the run stops. Both read-back paths
repair — verify_pages for programming, and write_differing, which is the
loader-update path where a page left wrong is a half-written loader slot.
That one is not hypothetical: deleting the discard made attiny85
pureboot.rehome fail deterministically there, the only flow still
assuming the old contract.

Protocol-visible, so README's W command says it: one W may program the
wrong bytes after a refused page, or after an application that
self-programmed entered without a reset, and a host that programs without
reading back cannot trust it.

Tests: pureboot.dirty drives the case the loader declines to guard — the
fixture application dirties every buffer word and jumps in with no reset
(hardware forbids that on a boot-sectioned mega, but simavr dispatches SPM
from anywhere, which is what makes it constructible) — and asserts a bare
verify sees the corruption, the repairing verify fixes it in one rewrite,
and it stays fixed. pbreloc asserts the same shape after a refusal.
test_planner covers the bound against a fake device: one bad write
repaired in a single rewrite, a page that never comes good stopping after
exactly three.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-22 16:29:27 +02:00
BlackMark
dd7490a3df build: generated presets and a check entry point 
tools/make_presets.py emits the uniform pipeline the hand-grown file had
drifted from — generated configure/build/test presets and workflows for
all 37 chips, reflect configure/build for libavr's 12-chip spot set —
and tools/check.sh runs every chip's workflow (--full adds the reflect
spot) as the port's gate.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 23:42:57 +02:00
BlackMark
bc24b63e65 host: one fact per line, progress bars, --verbose 
--info prints the decoded info block field by field and --fuses each
byte on its own line plus the BOOTSZ/BOOTRST meaning on boot-sectioned
megas. Transfers that take wire time draw a transient progress bar on
stderr when it is a tty — logs, pipes and the tests see only the
summary lines. -v/--verbose narrates decisions: knock counts, the
programming plan, update state handling and per-phase page counts.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 23:42:57 +02:00
BlackMark
332b244ac3 pureboot: every deployment axis is a build parameter 
Clock, baud, serial backend (hardware USART 0/1 or the software UART on
any pins) and the activation window all resolve through one CMake
function, pureboot_add_loader() in pureboot/CMakeLists.txt — the unit a
downstream project consumes. The default baud is the fastest standard
rate within 2.5 % (the same best-divisor search libavr's solver runs),
gated on software builds by the polled receiver's 100-cycles-a-bit
floor; every explicit pick is re-checked by the compile's static asserts.

The size matrix builds each axis that can move the image — backend x
clock ladder x USART instance, per chip — against the slot budget, and
two nondefault deployments run the whole protocol suite live: the 328P
on its shipped 1 MHz fuses over software serial on TX=PB1/RX=PB5
(pureboot.custom), and the 644A over USART1 (pureboot.usart1). The sim
runner takes -l to bridge any link, paces a fully quiet bridge toward
real time (a free-running 8 M-cycle window loses the reset-race knock),
and the fixture application speaks the deployment it is built for.

The loader itself shed bytes on the way: the return-address high byte
spelled through byteswap (the double swap folds to the one-byte pick),
the info-block address composed instead of bit_cast, and libavr's new
polled-UART helpers replacing the port's uart::detail reaches. Every
combination fits: 458-506 B across the megas' whole matrix, 470-484 B
on the tinies, 556-562 B in the 1284s' 1 KiB slot.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 23:42:57 +02:00
BlackMark
61b687120c pureboot: a loader in the staging slot is the staging copy — leave it there 
The update flow's first step wrote the staging content over whatever the
staging slot held; with a loader running right there (programmed by hand
onto erased flash), that write met the copy's own running-slot guard on
the composed through-word and the tool stopped at its verify — although
the copy is exactly an installed staging copy, able to stream the new
resident like any other. The install is now skipped when the slot holds a
complete loader: its info block where every image carries it, matching
the device's byte for byte, and the slot unchanged since the update began
(the state file's snapshot) — so a resumed half-written install still
differs from its snapshot and takes the install path, which completes it.
pbrehome gains the staging-slot position (an older build at stage
streaming a newer resident in); the README's wrong "cannot re-home from
the staging slot" claim is corrected.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 21:55:15 +02:00
BlackMark
ef58d5d363 pureboot: artifact roles, wrong-chip refusal, and misplaced-loader re-homing 
The README's deployment section now says what each build artifact is for:
the .hex is the programmer artifact (self-addressed into the top slot),
the .bin the self-update image — bare slot bytes a programmer would put
at address 0, where a boot-sectioned mega cannot even heal itself (SPM
only runs from the boot section) but a patched-vector chip runs the
position-independent copy and re-homes a build through the ordinary
--update-loader flow: the staging install and the word-0 redirect both
execute outside page 0's slot, so the running-slot guard never blocks it.
pbrehome.py is the acceptance test (misplaced at 0, guard intact,
re-home, app flash over the stale copy, banner); the staging slot is the
one position that cannot re-home itself, documented. The preflight's
wrong-chip refusal and loader_image's handling of padded images (peeled
to the slot content by the embedded base) are documented and the padded
case pinned in the planner.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 21:18:10 +02:00
BlackMark
03bb1f56cf pureboot: every libavr chip — 37 loaders, the m48 class, the 644 geometry 
The chip table becomes family blocks covering all 37 targets. The m48s
are a new deployment class: no boot section, so the tiny profile spoken
over the hardware USART — host-patched reset vector, trampoline
hand-over, a 510-byte budget (474 B built), no fuse preflight — while
their RWWSRE store stays the buffer discard (Atmel-8271 §26.2); the
device keys the patch flag and the CPU-halt waits on the curated
boot-section capability and the discard on the RWWSRE bit itself. The
644s' 64 KiB is exactly the 16-bit byte space: plain LPM, byte wire
addresses, 498 B in a 512-byte slot — and their 1 KiB minimum boot
section holds the resident and staging slots together, so self-update
needs no fuse step (the update test's slot pick now keys word-flash on
base >= 64 KiB; base + slot merely touching the boundary stays
byte-addressed). The 1284 joins the 1284P's word-addressed 1 KiB slot at
558 B. BOOT_FUSE gains every boot-sectioned family's ladder and fuse
byte; the planner exercises them all. The sim scaffolding keys
patch-vector-ness instead of the atmega name prefix, the fixture app
picks its clock by family (the tiny25/45/13 builds surfaced the 16 MHz
fallthrough as garbled banners), and the runner's wrapped flash ioctl
performs the m48 discard simavr's no-RWW cores turn into a stray buffer
fill. Sizes across the fleet: 466-504 B megas, 474 B m48s, 498 B 644s,
488-502 B tinies, 558 B 1284s — every chip passing
size/pi/planner/protocol/reloc/update.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 18:53:04 +02:00
BlackMark
6a5e313530 pureboot: correct the 1284P deployment profiles in the README 
The deployment section claimed the 1284P has no standalone profile, runs
BOOTSZ = 512 words always, and self-updates with no fuse change, reset
landing at 0x1f800 — internally contradictory (a 512-word section starts
at 0x1fc00, and the section holding both 1 KiB slots is 1024 words) and
contradicted by update_preflight, which refuses a self-update unless the
boot section covers two slots. The text described a 512-byte-slot
geometry this chip's loader cannot have. In truth the 328P profile table
maps onto the 1284P doubled: standalone = 512 words (the smallest
section is exactly the 1 KiB slot, reset at the loader base), self-update
= 1024 words with the loader-first reset walking the staging slot.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 16:48:46 +02:00
BlackMark
a28fccf475 pureboot: the 1284P rides a 1 KiB slot — its own boot-sector minimum 
The far machinery (ELPM reads, RAMPZ page commands, wire-word math)
costs ~46 B over the m328P's 504, and the tsb-calibrated C++-to-asm
gap says no implementation of this feature set reaches 512 on this
chip — a boundary its hardware does not have anyway: the 1284P's
smallest boot sector is 1 KiB. The slot therefore becomes
per-geometry (512 B, or 1 KiB past 64 KiB), which the host derives
from the word-addressing flag; slot arithmetic unifies (the index is
the wire high byte with its low bit dropped in either unit), the
update preflight demands a two-slot boot section in the chip's own
terms, and pbapp's hand-back jumps to the real slot base. libavr's
far primitives split their RAMPZ/Z asm operands (a page never
crosses 64 KiB, so callers keep a byte and a 16-bit cursor — the
32-bit address folds away; flash_load_far's byte form becomes the
out-RAMPZ+elpm pair avr-libc's pgm_read_byte_far rebuilds per call),
and the host splits reads at 64 KiB boundaries. All ten chips pass
the full suite — the 1284P at 558 B including protocol, relocation,
and the power-fail self-update — with pureboot byte-identical across
generated and reflect modes everywhere, and the original three
chips' images unchanged to the byte (488/502/504).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 13:54:40 +02:00
BlackMark
92503fbb2d pureboot: the classic megas and the word-addressed 1284P groundwork 
Device: boot-section detection probes SPMCR beside SPMCSR, the link
picks any hardware USART through the instance-aware lookups (URSEL
chips included), WDRF reads MCUSR-or-MCUCSR, and the >64 KiB shape
lands — word-addressed wire flash (info flag bit 1, page byte 0 means
256, base as a word address), far reads through flash_load_far, a
single 32-bit byte-cursor page walk (the 256-byte page wraps its low
byte exactly), and slot arithmetic in words (the return address
already is one). Host: addresses stay bytes internally and scale at
the wire, the boot-fuse decode becomes a per-signature table (byte
index + BOOTSZ ladder — the m168A's lives in EXTENDED), and the
planner tests pin every chip's ladder plus the word-addressed info
decode. Tests: the device runner serves every mega over the USART pty,
pbapp banners over the right link, the update rehearsal synthesizes
its assumed fuses from the tool's own table, and the PI lint tracks
the renamed info symbol. All six classic-mega/168A targets pass the
full suite (size, PI, planner, protocol, reloc, self-update) at
466–504 B; the 1284P builds await a libavr far-path slimming to make
its 512.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-21 12:00:19 +02:00
BlackMark
8ba023ed6b pureboot: take the device signature from the chip database 
libavr now exposes avr::hw::db.signature (compile-time, from the ATDF), so the
info block drops its per-chip hardcoded signature() for the db constant. The
loaders are byte-identical across modes with the correct signature, sizes
unchanged (488/502/504).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 23:38:20 +02:00
BlackMark
443fd39d31 build: emit a raw .bin beside the HEX for every loader image 
The host tool takes either form — load_image() parses Intel HEX by extension
and treats anything else as raw bytes — but the build emitted only the HEX, so
the raw path had no artifact behind it. The reloc and update tests each shell
out to objcopy at runtime to produce one for themselves.

add_hex_output becomes add_image_outputs and emits both forms. The .bin is
byte-identical to the plain `objcopy -O binary` those tests generate (-R .eeprom
strips nothing the loaders carry), and decodes equal to the HEX payload — 504 B
at 0x7e00 either way for pureboot. Sizes come out at the flash sizes exactly
(504/510/836/526), so nothing stretches to the .data load address.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-20 23:17:59 +02:00
BlackMark
08a0d77109 pureboot: take the emitted loader HEX for --update-loader 
The build emits an Intel HEX beside every loader image, but --update-loader
could not consume one: load_image() anchors every image at address zero, and
a loader HEX links at its base, so it decoded to a 32760-byte blob carrying
504 bytes of loader at the end. staging_content() then refused it as "loader
image is 32760 B, the slot holds 512" - an error naming neither the cause nor
the raw .bin the tool wanted instead.

Drop the blank below the base in the update path. The base comes from the
image's own info block rather than the device's, so an image built for
another target survives the slice intact and the preflight still reports it
as another target rather than failing to find an info block at all.

Verified on an ATmega328P: the full self-update flow driven straight from
pureboot_timeout-5s.hex, resident slot byte-for-byte against the image
afterwards, application preserved; both refusal paths unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-20 22:46:50 +02:00
BlackMark
260ab2e4e3 pureboot: drive the serial port on Windows too 
The host tool was standard-library-only but POSIX-only with it: termios and
select() bound the port layer, and importing termios failed outright on
Windows, so the module could not even load there.

Split Port into PosixPort (unchanged) and a WindowsPort over the Win32 serial
API through ctypes, picked by os.name; every call site keeps the Port name.
kernel32 only, so the standard-library constraint holds.

Windows has no select() for a COM handle, so the read deadlines move into the
driver as COMMTIMEOUTS, re-armed per read: read_available() ends on a gap
longer than a USB-serial latency timer coalesces (16 ms on FTDI parts),
read_exact() on the count or its deadline. Opening asserts DTR and RTS as a
POSIX open does, so a board wiring DTR to reset still pulses it. A failed
configuration closes the handle before raising - a COM handle is exclusive,
and the leak met the next open as "Access is denied". Win32 takes any integer
baud and a driver may accept one its hardware cannot produce (an FT232R
reports back a baud of 3 and keeps the old divisor), so obvious nonsense is
refused where termios' table would have.

Tested against an ATmega328P on COM6: info, fuses, both memories programmed
and verified, session reconnect, hand-over, the loader self-update, and the
write guard on its own slot. test_planner runs on Windows now as well.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-20 22:46:14 +02:00
BlackMark
e4aaf5bc62 build: emit an Intel-HEX beside every loader image 
avrdude programs Intel-HEX, not ELF, and the build produced only ELFs — so
flashing a loader to a real chip meant running objcopy by hand. add_hex_output()
hangs a POST_BUILD objcopy on each loader image: the three tsb tiers through
add_tsb_variant, pureboot, and the re-timed pureboot9. .eeprom is dropped, being
its own avrdude update.

It uses the toolchain file's CMAKE_OBJCOPY rather than a hardcoded path, so
every chip preset emits hex, not just the mega. pbapp keeps its ELF alone: the
update test converts it to a raw binary itself, and it is not a flashing target.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-20 21:57:26 +02:00
BlackMark
653602058a pureboot: PI lint, tightened gates, and the self-update test suite 
check_pi.py asserts the two link-time facts position independence rests on
(no absolute jmp/call; the info block within the image's first 256 bytes);
the size gates drop to 510 on the tinies for the trampoline word.

New per-chip tests beside the reworked protocol test: the planner units
(programming orders and their recovery properties, the surgery, staging
composition, boot-fuse decode, and the update preflight's error/warning
matrix over synthetic fuse bytes), the relocated-copy sweep (the identical
image installed one slot lower serves the full command set — the PI
acceptance test, and the one that caught the temporary-buffer trap), and
the self-update end-to-end: --update-loader to a re-timed build
(pureboot9, byte-different by PUREBOOT_TIMEOUT alone), then every
power-fail phase killed mid-write, restarted from the runner's flash dump,
and completed by a re-run with the application intact throughout. The mega
rounds run the BOOTRST-unprogrammed profile: the fixture application's 'L'
jump is the application-owned loader entry that profile relies on.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 19:37:57 +02:00
BlackMark
57d1c009cc pureboot: one position-independent binary — its own staging loader 
The image now runs from any 512-byte slot with every command intact:
control flow stays PC-relative, the write guard keys on the running slot
(the return-address anchor, computed once), the info block is addressed
from that same anchor as a byte pair (no absolute 16-bit address in the
image), and the application jump is an indirect call through a noipa-
laundered pointer to the absolute entry. 'J' — jump to a wire word
address, the one transfer primitive — replaces 'G': the host knows the
application entry from the info block, and moving between loader copies
needs arbitrary targets. The activation window is a compile-time 8 s
(PUREBOOT_TIMEOUT overrides), counted as a single calibrated poll loop.

A refused page no longer poisons the write-once temporary buffer (a real
silicon trap: the next write would program the drained data): every page
write discards the buffer first — CTPB on the tinies, on the mega the same
RWWSRE store that re-enables RWW after programming. The tinies' post-op
busy-waits go with it: their CPU halts through page erase and write.

488 / 502 / 504 B on t13a / t85 / mega — under the tinies' 510-byte budget,
whose last slot word is the host-managed trampoline: the resident's holds
the application entry, a staging copy's the jump through which an abandoned
update still times out into a loader.

The host tool updates the loader with itself: --update-loader installs the
identical image one slot below the resident, jumps into it, lets it rewrite
the resident, and restores the staging region from a state file — each
phase idempotent off the flash state, resumable after any interruption
(t13a: the staging slot carries the reset vector, written last in and
first out; t85: word 0 redirected around the resident rewrite; mega:
fuse-matrix preflight with a hard BOOTSZ gate and --assume-fuses for
simulators). Application flashing recovers by reset from any interruption:
patched page 0 and trampoline first, erase descending, and a walk-region
refusal behind --force on BOOTRST-below-loader megas.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 19:37:43 +02:00
BlackMark
06bb06d994 pureboot: harden the sim device runner 
Cancel the GPIO bridge's cycle timers with the state they drive: avr_reset
drops the TX latch, whose falling edge starts a spurious decode before
bridge_reset runs, and the stale sampler then interleaves with the loader's
first real answer through the shared shift state — the first post-reset
replies came back corrupted and the knock retries burned the activation
window into the application.

Wrap the mega's registered flash ioctl to re-dispatch page erases with Z
masked to the page boundary: simavr's PGERS handler erases spm_pagesize
bytes from Z & ~1 (its PGWRT path masks correctly), wiping the neighbouring
page when Z sits past the page start, which hardware permits (§26.8.1).
Model the write-once temporary buffer in the tiny NVM module — silicon
refuses a second load per word until the buffer clears, and a last-write-
wins model masks real firmware bugs.

Optional arguments select the reset vector (the mega's fuse profiles) and a
raw flash image to resume from (power-fail tests re-enter a dumped state).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 19:37:10 +02:00
BlackMark
9a9a7ef0e8 pureboot: review-pass fixes to the host tool and device runner 
pureboot.py: reject an empty image file with a clear error instead of
an IndexError deep in the vector-surgery planner; tighten the erase
docstring (order is irrelevant there — every target byte is the same
value, unlike a real flash where page 0 must go last).

pureboot_device.c: the GPIO bridge's bit_cycles used plain truncating
division where the firmware computes its own bit period with
round-to-nearest (uart.hpp: (Clock.hz + Baud.bd/2)/Baud.bd) — one
cycle off per bit on both tinies, harmless in practice but needless
drift against a firmware built to a different constant. Matched
exactly. Also clear the queued-bytes/decode-in-progress bridge state
on the test-only reset signal, so a future reset-mid-transfer scenario
can't feed a freshly reset chip bytes queued for its previous life.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 10:45:19 +02:00
BlackMark
4acf358dda pureboot: gitignore python bytecode cache 
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 10:43:56 +02:00
BlackMark
11c10f986d pureboot: stop tracking the python bytecode cache 
A stray __pycache__/*.pyc from a local test run got swept into the
previous commit's git add. Untracked and gitignored.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 10:43:36 +02:00
BlackMark
f587f0a26e pureboot: host tool and end-to-end protocol tests, all three chips 
pureboot.py (Python stdlib only): images as raw binary or Intel HEX,
flash and EEPROM programming with read-back verify, erase composites,
fuse and info readout, activation-timeout configuration, and the
tinies' reset-vector surgery — the trampoline word below the loader,
page 0 written last.

The test spawns a simavr device (pureboot_device.c) — the mega's USART
as a pty; on the tinies a cycle-timed GPIO<->pty bridge for the polled
software UART plus the NVM module simavr's tiny cores lack (their SPM
opcode ioctls into a void and silently does nothing) — and drives it
with the real tool: knock from reset (erased-flash walk on the tinies),
program and verify both memories, timeout write, session reconnect, an
external reset through the patched vector, hand-over, and the fixture
application's banner. Results are cross-checked against ground-truth
memory dumps and an independent decode of the surgery's rjmp words,
red-verified against a sabotaged encoder.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 05:54:15 +02:00
BlackMark
27c768a102 pureboot: the device — one pure C++ source, 512 bytes, every chip 
No inline assembly, no global register variables; libavr does the
datasheet work. The device speaks primitives — flash read/page-program,
EEPROM read/write, fuse read, info block, EEPROM-resident activation
timeout, hand-over — and verify, erase, reset-vector surgery, and
timeout configuration live in the host tool. 490 B on the ATtiny13A,
510 B on the ATtiny85, 484 B on the ATmega328P, each linked into the
top 512 bytes of flash; per-chip size tests gate all three.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 05:33:28 +02:00
BlackMark
d989b5b8cd tsb: third size pass — restructure to the oracle's shape 
The second pass concluded the 168 B tricks->asm gap was per-call ABI
cost. Most of it was structure. Rebuilt around the oracle's own shape —
argless noinline primitives over a whole-loader call-saved register
protocol (g_addr in Y, count r16, window r7, direction latch r6), a
top-down erase_below whose loop tests against zero and hands callers
g_addr = 0 for free, bounded rx everywhere (a silent host unwinds to
the app from any state, as the oracle does), and a named tsb_app entry
that --pmem-wrap-around=32k relaxes to the wrapped rjmp:

  tsb_asm    510 B in the 512 B section (oracle: 500), C++ except rx
             and the page-store loop — the two routines whose remaining
             cost is the calling convention itself (~30 asm lines, was
             ~280)
  tsb_tricks 526 B, no assembly at all (was 666)
  tsb_pure   836 B, still one readable function per command (was 842)

Every g_* update placement works around a GCC 16.1 wrong-code bug
(stores into global register variables deleted when only callees read
them — repro and rules in libavr dev/lessons.md). Also fixes two
latent hardware bugs all earlier tiers carried, masked by simavr's
zeroed register file: the crt-less entries never established
__zero_reg__ = 0, and the direction latch was read before written —
power-on registers are undefined.

All tiers full oracle feature parity, protocol tests green in both
libavr modes, .text byte-identical across modes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
 2026-07-20 01:00:27 +02:00
BlackMark
314e422b19 tsb: beat the first-pass size floors (tricks 666, pure 842) 
tricks 778->666: always_inline every single-call handler into the
[[noreturn]] reset entry (which pays no prologue, so their push/pop of
call-saved registers vanishes), walk the page pointer in Y (adiw, base
recovered as g_addr-page) instead of recomputing Z=base+offset, bring
the UART up in the two registers that are not already at their reset
value, and seed the activation counter as __uint24.

pure 896->842: TU-local internal linkage (proper hygiene, and it lets
the compiler inline the one-call handlers), a byte-wide activation
count, __uint24 timeout. Still one readable function per command.

asm unchanged at 498: its C++-expressible parts are already C++; the
core stays asm (the 666 B all-tricks tier is 168 B over — per-call ABI
tax, not a feature). All three cross-mode byte-identical, protocol green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-19 20:15:49 +02:00
BlackMark
3e0717ef06 tsb: drive each tier to its size floor 
asm 502->498 B (below the oracle's 500): the stack bring-up moves to plain C++,
and a register is reserved for the config-page high byte instead of reloading it
at each app-flash-boundary compare. tricks 808->778 B: shared erase/rww helpers
plus the libavr half-duplex W1C fix. pure 950->896 B and no SRAM: streams
rx->SPM/EEPROM instead of staging a 128 B page buffer. All three keep full oracle
feature parity and stay byte-identical across modes; protocol tests (round-trip +
password + emergency erase) green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-19 18:47:38 +02:00
BlackMark
812be910c1 tsb: document the three tiers at full parity in the build file 
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-19 16:50:18 +02:00
BlackMark
34529c8031 tsb: protocol test covers the password gate and emergency erase 
Each scenario group now runs on its own freshly-reset device: the round-trip
on a blank config page, plus a password-config device that must be sent the
password after the knock to activate, and an emergency-erase device where a
0-byte + two confirms wipes flash, EEPROM and the config page (verified by
reading all three back as 0xff). All three tiers pass every group.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-19 16:49:20 +02:00
BlackMark
06bd56af50 tsb: pure and tricks tiers reach full oracle feature parity 
Both tiers gain the features the asm tier already carries — one-wire
half-duplex (via libavr's new .half_duplex), the config-page activation
timeout, and emergency erase (password \0 + double-confirm wipes flash,
EEPROM and the config page) — on top of the watchdog bail, password gate and
config/flash/EEPROM read-write they already had. pure stays idiomatic
(flash_table info block, one function per command) at 950 B; tricks keeps its
compiler trickery (call-saved global-register page walk, unified runtime-flag
paths pinned noinline/noclone, streaming stores, arithmetic command decode)
at 808 B. Both byte-identical across generated and reflect modes; the size
gradient across the three tiers is now 502 / 808 / 950 B.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-19 16:47:21 +02:00
BlackMark
75bb84fa3e tsb: asm tier reaches full oracle feature parity at 502 B 
Rewrite the inline-asm tier so it matches the hand-written fixed-baud oracle's
feature set inside the 512 B boot section: watchdog-reset bail, one-wire
half-duplex (RXEN/TXEN toggled per direction, TX turnaround guard),
config-page activation timeout, the password gate (wrong byte hangs draining
the UART), emergency erase (password \0 + double-confirm wipes flash, EEPROM
and the config page), and config/flash/EEPROM read-write. Every geometry,
baud and info-block constant comes from libavr consteval; only the dense
control flow is hand-written. 502 B, byte-identical across generated and
reflect modes.

Test harness: seed the config page from TSB_CONFIG so the password and
emergency-erase paths are exercisable, and clear simavr's AVR_UART_FLAG_POLL_
SLEEP — a host-CPU-saving usleep(1)-per-idle-poll hack that models no hardware
and paces a one-wire loader (which releases TX between bytes) in real time,
distorting protocol timing.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-19 16:23:16 +02:00
BlackMark
778b8a0100 tsb: vendor the fixed-baud assembly oracle as the size/feature bar 
The Seed Robotics native-UART fixed-baud TinySafeBoot (GPLv3), reference
only — not built. Assembles to 500 B with the full feature set, proving
≤512 B and full feature parity are simultaneously reachable. Also drops the
stale empty stk500v2/ leftover.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
 2026-07-19 15:29:58 +02:00
BlackMark
48d11fe8e3 tsb: use the named register surface 
Direct register access now reads through the named surface
(hw::mcusr::wdrf.test(), hw::ucsr0b::write(...)) instead of the string form,
matching how libavr itself is written. Zero-overhead: pure 740 B, tricks 658 B,
asm 508 B unchanged, all byte-identical across modes, protocol green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-19 14:55:01 +02:00
BlackMark
bb4784ae0c tsb: refactor the pure tier onto libavr sugar 
The showcase tier now leans on the helpers it fed back instead of reaching under
them: the info block is an avr::flash_table (no raw [[gnu::progmem]]), a page is
filled with spm::fill(addr, span) (no hand-packed lo|hi<<8 loop), and the
WDT-reset bail reads field<"MCUSR","WDRF">::test() (no read() & {}(1).value).

Zero-overhead throughout: .text stays 740 B, byte-identical across generated and
reflect modes, protocol test green. The info block streams through the existing
address-based send_flash rather than a range-for over the flash_table — the
range-for is a distinct loop that cannot share the loader's one flash streamer,
so it would add 14 B for no functional gain.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-19 13:33:53 +02:00
BlackMark
d07586652d tsb: slim the port branch to the libavr reimplementation 
main carried the whole pre-libavr tree beside the port: the other-bootloader
directories (blink, stk500v2), the Atmel Studio solution/project, and — dead in
the tsb dir itself — four submodule links to the superseded io/flash/uart/type
libraries the libavr sources never include. None are build inputs; CMake drives
the three variants through FetchContent. master keeps the full legacy tree
untouched.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-19 13:12:56 +02:00
BlackMark
3a2f2a23c2 tsb: drop the local -O3 strip, now handled by the libavr toolchain 
The -O3 leak is fixed upstream (cmake/release-os.cmake via CMAKE_PROJECT_INCLUDE),
so the port no longer needs its own string(REPLACE); a Release build is -Os
through the toolchain file. Verified: all three variants build at their sizes
(508/658/740) and pass the size + protocol ctest.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-19 10:52:13 +02:00
BlackMark
4fa058653e tsb: reimplement TinySafeBoot on libavr in three size tiers 
The native-UART fixed-baud TinySafeBoot protocol, ported onto libavr as a
crt-free boot-section loader, in three variants that trade clarity for size:

  tsb_pure   740 B  idiomatic C++: SRAM page buffer, separate flash/EEPROM
                    leaves, shared framing; the polled `unused` guard posture.
  tsb_tricks 658 B  unified runtime-flag paths (noinline/noclone), call-saved
                    global-register page walk — attributes only, no asm.
  tsb_asm    508 B  streaming store + hand-rolled UART/SPM/EEPROM/erase loops;
                    fits the 512 B boot section (BOOTSZ=11). Trims the optional
                    password gate and WDT-reset bail — unreachable in C++ with
                    both (hand-asm is ~15 % denser). Tiers 1-2 keep them and
                    live in the 1 KB section they fit.

All three are .text byte-identical across libavr's generated and reflect modes.
The CMake build strips the leaked -O3 (a Release build is silently -O3, not the
-Os this loader is measured against) and gates each variant's size against its
section. A simavr harness (test/device.c + test/tsbtest.py) drives the real wire
protocol over a pty and flashes the device; the size and protocol tests run in
ctest. Verified byte-for-byte against the reference tsbloader_adv (C#/mono):
activate, read info, flash write + verify.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
 2026-07-19 05:00:51 +02:00
BlackMark
14ac91c815 Update uart submodule 2020-04-13 17:20:31 +02:00
BlackMark
621d34cc18 Update uart submodule 2020-04-13 13:08:34 +02:00
BlackMark
0a65626975 Update uart submodule to fix 115200 baud with 16 MHz 2020-04-13 00:22:02 +02:00
BlackMark
9390f7830b Add small blink example as bootloader payload test 2020-04-12 18:45:33 +02:00
BlackMark
b21673e326 Uncomment setting stack pointer to allow jumping into bootloader 2020-04-12 18:43:53 +02:00
BlackMark
3afda0ebf9 Replace function call to user code with jump 2020-04-12 16:05:16 +02:00
BlackMark
807b1f336f Finish bootloader by adding jump to user code 2020-04-12 15:32:31 +02:00
BlackMark
5f8d6a6f85 Fix chip erase followed immediately by flash programming 2020-04-12 15:12:02 +02:00
BlackMark
41f81247ce Improve semantics for chip erase state enum 2020-04-12 15:07:58 +02:00
BlackMark
a72bf67b07 Fix flash memory address being a word-address 2020-04-12 13:10:00 +02:00
BlackMark
3a04b1f488 Add topcard detection for avrdude 2020-04-12 12:01:53 +02:00
BlackMark
8979066420 Fix receiveByte timeout and add global timeout 2020-04-12 11:47:11 +02:00
40 changed files with 3414 additions and 1402 deletions
Expand all files Collapse all files

4
.clang-format
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@@ -1,13 +1,15 @@
---
BasedOnStyle: LLVM
Standard: Latest
ColumnLimit: 120
IndentWidth: 4
TabWidth: 4
UseTab: ForIndentation
AlignEscapedNewlines: DontAlign
AllowShortFunctionsOnASingleLine: Empty
AlwaysBreakTemplateDeclarations: true
BreakTemplateDeclarations: Yes
BreakBeforeBraces: Custom
BraceWrapping:
AfterFunction: true
InsertBraces: true
...

38
.clangd Normal file
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@@ -0,0 +1,38 @@
# Editor accommodations for the second frontend. No compilation database is
# named here: this repo rides as a submodule in its consumers, and this file
# travels with it — a consumer's own database then covers these sources, with
# that project's loader flags. The checkout that is opened as a folder names
# its build tree in .vscode/settings.json instead.
CompileFlags:
Add:
# clang has no 24-bit integer and GCC's are keywords, not macros, so the
# editor needs a stand-in for avr::uint24_t. The next width up is the only
# one available — clang rejects _BitInt(24) on this target.
- -D__uint24=unsigned long
- -D__int24=long
# clangd forwards the driver's system includes but not its own header
# directory, so <stdint.h> resolves to avr-libc's, which still gates the
# limit and constant macros on the C++98 opt-in.
- -D__STDC_LIMIT_MACROS
- -D__STDC_CONSTANT_MACROS
# isr::emit spells a vector number into [[gnu::signal(N)]], which clang
# rejects rather than ignores — enough of them in one TU to reach the
# default limit of 19 inside the headers and truncate the parse.
- -ferror-limit=0
Remove:
# Codegen shaping the loader TUs carry and clang has no spelling for.
- -fira-algorithm=*
- -fno-split-wide-types
- -fno-tree-ter
- -fno-ivopts
- -fno-move-loop-invariants
# The build promotes warnings for the compiler that has to be right about
# them; in the editor the flag paints a second frontend's opinions in the
# colour reserved for things that do not compile.
- -Werror
Diagnostics:
Suppress:
# clang's AVR `signal` attribute takes no arguments and it knows none of
# progmem, naked or OS_main. A misspelling is what the build is for.
- attribute_wrong_number_arguments
- unknown-attributes

13
.gitattributes vendored
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@@ -1,8 +1,11 @@
*.h eol=lf
*.hpp eol=lf
*.c eol=lf
*.cpp eol=lf
.git* eol=lf
# Line endings are the repository's, not the editing machine's: this checkout
# is reached from two hosts, and a file rewritten by a Windows tool comes back
# with every line changed unless something says otherwise. Naming the source
# extensions left Markdown, Python, shell and CMake to whatever the writing
# tool defaulted to, which is CRLF on one of the two.
* text=auto eol=lf
# Atmel Studio writes these and expects them back.
*.vcxproj* eol=crlf
*.cppproj eol=crlf
*.sln eol=crlf

10
.gitignore vendored
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@@ -9,3 +9,13 @@ Debug
*.eeprom
*.lss
*.map
# CMake / clangd
/build/
/local/
compile_commands.json
.cache/
# Python
__pycache__/
*.pyc

27
.gitmodules vendored
View File

@@ -1,24 +1,3 @@
[submodule "tsb/io"]
path = tsb/io
url = git@git.blackmark.me:avr/io.git
[submodule "tsb/flash"]
path = tsb/flash
url = git@git.blackmark.me:avr/flash.git
[submodule "tsb/uart"]
path = tsb/uart
url = git@git.blackmark.me:avr/uart.git
[submodule "tsb/type"]
path = tsb/type
url = git@git.blackmark.me:avr/type.git
[submodule "stk500v2/type"]
path = stk500v2/type
url = git@git.blackmark.me:avr/type.git
[submodule "stk500v2/io"]
path = stk500v2/io
url = git@git.blackmark.me:avr/io.git
[submodule "stk500v2/uart"]
path = stk500v2/uart
url = git@git.blackmark.me:avr/uart.git
[submodule "stk500v2/flash"]
path = stk500v2/flash
url = git@git.blackmark.me:avr/flash.git
[submodule "libavr"]
path = libavr
url = ../libavr.git

6
.vscode/extensions.json vendored Normal file
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@@ -0,0 +1,6 @@
{
"recommendations": [
"llvm-vs-code-extensions.vscode-clangd",
"ms-vscode.cmake-tools"
]
}

36
.vscode/settings.json vendored Normal file
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@@ -0,0 +1,36 @@
{
// clangd is the language server; the cpptools engine would parse every file
// a second time and disagree, since nothing tells it about a cross
// compiler.
"C_Cpp.intelliSenseEngine": "disabled",
// --query-driver lets clangd ask the cross compiler for its own system
// includes and target. The database is named here rather than in .clangd
// because that file travels with the driver into a consumer's submodule,
// where a build tree of this repo's own need not exist.
"clangd.arguments": [
"--compile-commands-dir=${workspaceFolder}/build/atmega328p-generated",
"--query-driver=**avr-g++*",
"--header-insertion=never"
],
// The presets are the build interface, and the toolchain file inside the
// libavr submodule is the one place the compiler is chosen. **No prefix is
// named here**: a committed file may not name a path that is true of one
// machine (libavr guidance rule 50), so the gitignored local/machine.cmake
// at this repository's root is where a checkout says where its toolchain
// is - one file, and it answers for both hosts.
"cmake.useCMakePresets": "always",
"cmake.configureOnOpen": true,
"cmake.options.statusBarVisibility": "compact",
"files.watcherExclude": {
"**/build/**": true,
"**/libavr/**": true
},
"files.associations": {
".clangd": "yaml",
".clang-format": "yaml"
}
}

157
CMakeLists.txt Normal file
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@@ -0,0 +1,157 @@
cmake_minimum_required(VERSION 3.28)
project(tsb_libavr LANGUAGES CXX)
# libavr rides as the pinned submodule; LIBAVR_ROOT (cache or environment)
# overrides it for tandem development against a working tree. The toolchain
# file comes from the submodule via CMakePresets.json either way.
if(NOT LIBAVR_ROOT AND DEFINED ENV{LIBAVR_ROOT})
set(LIBAVR_ROOT $ENV{LIBAVR_ROOT})
endif()
if(NOT LIBAVR_ROOT)
set(LIBAVR_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/libavr)
endif()
if(NOT EXISTS ${LIBAVR_ROOT}/CMakeLists.txt)
message(FATAL_ERROR "libavr not found at ${LIBAVR_ROOT} - run: git submodule update --init libavr")
endif()
add_subdirectory(${LIBAVR_ROOT} libavr-build)
include(${LIBAVR_ROOT}/cmake/checks.cmake)
if(PROJECT_IS_TOP_LEVEL)
add_compile_options(-Werror) # warnings are errors for the port's own code
enable_testing()
# Rules 11 and 33 over this repo's own sources. The oracle's assembly needs
# no exclusion: it is neither formatted nor ASCII-checked, being in neither
# glob, which is the right answer for a vendored reference whose text is
# the artifact.
libavr_format_test()
# The behavioral tests drive the real wire protocols over a simavr pty
# (as the host tools do) and actually flash the device. The runner is a
# host program built at configure time against libsimavr (C++23 - what the
# distribution's compiler speaks in full).
#
# **A host that cannot build it registers those tests anyway and skips
# them.** They used to be left out, which makes the suite a different size
# on a different machine - and a suite whose size is a property of the
# machine is one nothing can be compared against.
set(TSB_DEVICE ${CMAKE_BINARY_DIR}/tsb_device)
find_program(_host_cxx NAMES c++ g++)
set(_tsb_absent "${LIBAVR_NO_PYTHON}")
if(NOT _host_cxx)
set(_tsb_absent "no host C++ compiler on PATH, and the simavr device is a host program")
elseif(NOT _tsb_absent)
execute_process(
COMMAND ${_host_cxx} -std=c++23 -Wall -Wextra -O2
-I/usr/include/simavr -I/usr/include/simavr/parts
-o ${TSB_DEVICE} ${CMAKE_CURRENT_SOURCE_DIR}/test/device.cpp
-lsimavr -lsimavrparts -lelf
RESULT_VARIABLE _dev_res ERROR_VARIABLE _dev_err)
if(NOT _dev_res EQUAL 0)
# One bounded line of it: this becomes a single argument on a
# command line, and the reading has to say what stopped the build
# rather than that something did.
string(REGEX REPLACE "[\r\n\t]+" " " _dev_err "${_dev_err}")
string(REPLACE ";" "," _dev_err "${_dev_err}")
string(LENGTH "${_dev_err}" _dev_len)
if(_dev_len GREATER 240)
string(SUBSTRING "${_dev_err}" 0 240 _dev_err)
endif()
set(_tsb_absent "test/device.cpp does not build here: ${_dev_err}")
endif()
endif()
libavr_launcher(_tsb_python "${_tsb_absent}" ${Python3_EXECUTABLE})
if(_tsb_absent)
message(STATUS "the protocol tests skip here - ${_tsb_absent}")
endif()
endif()
# The ELF is only a container (symbols, section headers) and is never flashed -
# and the host tool's load_image() dispatches on extension, so handing it one
# would silently program the header bytes. Every loader image therefore gets
# both flashable forms beside it at link time: .hex for avrdude, and .bin for
# the host tool's raw path (which is what the reloc and update tests convert to
# on the fly). .eeprom is dropped - EEPROM content is its own update.
function(add_image_outputs name)
add_custom_command(TARGET ${name} POST_BUILD
COMMAND ${CMAKE_OBJCOPY} -O ihex -R .eeprom
$<TARGET_FILE:${name}> $<TARGET_FILE:${name}>.hex
COMMAND ${CMAKE_OBJCOPY} -O binary -R .eeprom
$<TARGET_FILE:${name}> $<TARGET_FILE:${name}>.bin)
endfunction()
# The TinySafeBoot protocol reimplemented on libavr in variants that trade
# clarity for size. Each links into the ATmega328P boot section (BOOTSZ selects
# its size; BOOTRST vectors a reset to its base) with -nostartfiles - a polled
# loader has no use for the crt or the vector table. The entry sits in
# .vectors, laid first, and runs - avr::startup::entry on the policy tier,
# the experiment tiers' own naked stubs elsewhere, each documented in its
# source. The boot base is FLASHEND+1 minus the section size; the linker
# section-start and the source's boot_bytes agree. tsb_app is
# the application's reset vector, pinned to 0 here so the loaders jump to a
# named function; --pmem-wrap-around lets relaxation turn that absolute jump
# into the wrapped rjmp AVR's modulo-flash PC actually executes.
# All four implement the full oracle feature set (see oracle/README.md):
# watchdog bail, one-wire half-duplex, config-page activation timeout, password
# gate, emergency erase, config/flash/EEPROM read-write. They differ only in how,
# and the size gradient is the cost of that "how".
# tsb_asm - the tricks tier's C++ with exactly two routines in asm: the
# bounded rx and the page-store loop, the two whose remaining
# cost is the C ABI itself. Everything else, bring-up to
# dispatch, is C++ on libavr.
# tsb_tricks - no asm at all: the whole-loader register allocation lives in
# global register variables (Y walks the page pointer), every
# helper is a tiny noinline primitive placed by the
# global-register store rules, pages stream straight to
# SPM/EEPROM.
# tsb_pure - pure idiomatic libavr, one function per command, TU-local
# (internal linkage), streaming (no SRAM page buffer).
# tsb_policy - the policy floor: no inline assembly and no global register
# variables, which is philosophy #5's own bound, and the
# measured evidence that the 512 B fit is a property of the
# mechanisms it bans.
#
# What each measures is oracle/README.md's table, which is the one place the
# four numbers and the hand-written loader's own are compared.
#
# add_tsb_variant(<name> <boot-section-bytes>)
function(add_tsb_variant name bytes)
math(EXPR base_dec "32768 - ${bytes}")
math(EXPR base_hex "${base_dec}" OUTPUT_FORMAT HEXADECIMAL)
add_executable(${name} tsb/${name}.cpp)
target_link_libraries(${name} PRIVATE libavr)
target_link_options(${name} PRIVATE -nostartfiles -Wl,--section-start=.text=${base_hex}
-Wl,--defsym=tsb_app=0 -Wl,--pmem-wrap-around=32k)
add_custom_command(TARGET ${name} POST_BUILD COMMAND ${CMAKE_SIZE} $<TARGET_FILE:${name}>)
add_image_outputs(${name})
if(PROJECT_IS_TOP_LEVEL)
add_test(NAME ${name}.size
COMMAND ${CMAKE_COMMAND} -DSIZE_TOOL=${CMAKE_SIZE} -DELF=$<TARGET_FILE:${name}>
-DLIMIT=${bytes} -P ${CMAKE_CURRENT_SOURCE_DIR}/test/check_size.cmake)
add_test(NAME ${name}.protocol
COMMAND ${_tsb_python} ${CMAKE_CURRENT_SOURCE_DIR}/test/tsbtest.py
${TSB_DEVICE} $<TARGET_FILE:${name}> ${base_hex})
endif()
endfunction()
# The tiers reimplement the ATmega328P-only reference protocol, so the guard is
# the whole of what this repo builds.
if(LIBAVR_MCU STREQUAL "atmega328p")
add_tsb_variant(tsb_asm 512)
add_tsb_variant(tsb_policy 1024)
add_tsb_variant(tsb_pure 1024)
add_tsb_variant(tsb_tricks 1024)
# The policy tier's floor needs these two: a loader's loop bodies all
# contain calls, which is what makes hoisting an invariant out of one cost
# more than it saves. The other tiers keep the flag set their recorded
# floors were measured with - none.
target_compile_options(tsb_policy PRIVATE -fno-move-loop-invariants -fno-tree-ter)
endif()
# Every test registered above carries the marker a stubbed launcher prints, so
# a check this host cannot run reads as Skipped rather than Failed.
if(PROJECT_IS_TOP_LEVEL)
libavr_skip_unverified()
endif()

84
CMakePresets.json Normal file
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@@ -0,0 +1,84 @@
{
"version": 8,
"configurePresets": [
{
"name": "base",
"hidden": true,
"generator": "Ninja",
"binaryDir": "${sourceDir}/build/${presetName}",
"toolchainFile": "${sourceDir}/libavr/cmake/avr-toolchain.cmake",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Release",
"CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
"CMAKE_COLOR_DIAGNOSTICS": "ON"
}
},
{
"name": "atmega328p-generated",
"inherits": "base",
"cacheVariables": {
"LIBAVR_MCU": "atmega328p",
"LIBAVR_REFLECT": "OFF"
}
},
{
"name": "atmega328p-reflect",
"inherits": "base",
"cacheVariables": {
"LIBAVR_MCU": "atmega328p",
"LIBAVR_REFLECT": "ON"
}
}
],
"buildPresets": [
{
"name": "atmega328p-generated",
"configurePreset": "atmega328p-generated"
},
{
"name": "atmega328p-reflect",
"configurePreset": "atmega328p-reflect"
}
],
"testPresets": [
{
"name": "atmega328p-generated",
"configurePreset": "atmega328p-generated",
"output": {
"outputOnFailure": true
}
}
],
"workflowPresets": [
{
"name": "atmega328p-generated",
"steps": [
{
"type": "configure",
"name": "atmega328p-generated"
},
{
"type": "build",
"name": "atmega328p-generated"
},
{
"type": "test",
"name": "atmega328p-generated"
}
]
},
{
"name": "atmega328p-reflect",
"steps": [
{
"type": "configure",
"name": "atmega328p-reflect"
},
{
"type": "build",
"name": "atmega328p-reflect"
}
]
}
]
}

28
bootloader.atsln
View File

@@ -1,28 +0,0 @@
Microsoft Visual Studio Solution File, Format Version 12.00
# Atmel Studio Solution File, Format Version 11.00
VisualStudioVersion = 14.0.23107.0
MinimumVisualStudioVersion = 10.0.40219.1
Project("{E66E83B9-2572-4076-B26E-6BE79FF3018A}") = "tsb", "tsb\tsb.cppproj", "{DCE6C7E3-EE26-4D79-826B-08594B9AD897}"
EndProject
Project("{E66E83B9-2572-4076-B26E-6BE79FF3018A}") = "stk500v2", "stk500v2\stk500v2.cppproj", "{19798CCE-5D96-40E9-B769-D209715DCE0C}"
EndProject
Global
GlobalSection(SolutionConfigurationPlatforms) = preSolution
Debug|AVR = Debug|AVR
Release|AVR = Release|AVR
EndGlobalSection
GlobalSection(ProjectConfigurationPlatforms) = postSolution
{DCE6C7E3-EE26-4D79-826B-08594B9AD897}.Debug|AVR.ActiveCfg = Debug|AVR
{DCE6C7E3-EE26-4D79-826B-08594B9AD897}.Debug|AVR.Build.0 = Debug|AVR
{DCE6C7E3-EE26-4D79-826B-08594B9AD897}.Release|AVR.ActiveCfg = Release|AVR
{DCE6C7E3-EE26-4D79-826B-08594B9AD897}.Release|AVR.Build.0 = Release|AVR
{19798CCE-5D96-40E9-B769-D209715DCE0C}.Debug|AVR.ActiveCfg = Debug|AVR
{19798CCE-5D96-40E9-B769-D209715DCE0C}.Debug|AVR.Build.0 = Debug|AVR
{19798CCE-5D96-40E9-B769-D209715DCE0C}.Release|AVR.ActiveCfg = Release|AVR
{19798CCE-5D96-40E9-B769-D209715DCE0C}.Release|AVR.Build.0 = Release|AVR
EndGlobalSection
GlobalSection(SolutionProperties) = preSolution
HideSolutionNode = FALSE
EndGlobalSection
EndGlobal

67
ide/README.md Normal file
View File

@@ -0,0 +1,67 @@
# Atmel Studio
`master` carries `bootloader.atsln`, so this branch does too: `ide/bootloader.atsln`
builds the loader from the same source Ninja does, to a **byte-identical
`.text`** — the `tsb_asm` tier in its 512-byte section (`check-flags.py` below
is what holds the flag sets equal, so the size is Ninja's own). CMake remains
the build system; the solution is here so the port opens in Studio as its
predecessor did.
## One project, of four tiers
A `.cppproj` is one binary at one set of flags. `tsb_asm` is the tier that
occupies the same 512-byte section `master`'s `tsb` project targeted, which is
the one worth opening in Studio.
The other three tiers (`tsb_pure`, `tsb_tricks`, `tsb_policy`) are not here.
They differ from `tsb_asm` in their source file, their section size, and — for
`tsb_policy` — two loop flags; nothing about that is a Studio concern, and what
they exist to demonstrate is a size gradient only the CMake size tests measure.
Adding one is a copy of `tsb_asm/tsb_asm.cppproj` in its own directory, with its
name, its GUID, its source path and its `--section-start` changed (`0x7c00` for
the 1 KiB tiers), plus four lines in the solution.
`avrdevice` is a project property, so each project gets its own directory:
Studio builds into `<project dir>/<Configuration>` whatever `OutputDirectory`
says, and two projects sharing a directory would share one object file.
## Debug keeps `-Os`
Both configurations compile at `-Os`; Debug adds only `-gdwarf-4`. The `.text`
is therefore identical in both, which is the point — a loader's section is a
**correctness** bound and not a budget. A debug configuration that silently
overruns the section is worse than none, and DWARF costs no flash, so the
optimisation level stays where correctness needs it.
## What Studio needs from the machine
libavr from the **submodule**, found at
`$(MSBuildProjectDirectory)\..\..\libavr\include` — correct by construction, and
anchored to the project because a plain relative path resolves against the
generated makefile's directory (the configuration's output directory), not the
project's. There is no `LIBAVR_ROOT` escape hatch: a variable exported in a
shell is invisible to Studio launched from the Start menu, and the failure reads
as a missing `libavr/libavr.hpp` — which is what the submodule answers.
A GCC 16.1 toolchain registered as flavour `avr-g++-16.1.0`, nothing older
reaching `-std=c++26`.
## Generating and gating
One generated file is required before the project will load at all, and one
command checks the flags have not drifted (both from libavr's
`tools/atmelstudio/`):
```sh
python libavr/tools/atmelstudio/componentinfo.py \
ide/tsb_asm/tsb_asm.componentinfo.xml --device ATmega328P
python libavr/tools/atmelstudio/check-flags.py \
--solution ide/bootloader.atsln --project tsb_asm --target tsb_asm \
--compile-commands build/atmega328p-generated/compile_commands.json \
--log build/as-tsb_asm.log
```
Release is what the gate compares — the presets define no debug build, and
Debug differs from Release only in `-gdwarf-4`.
Legacy (the yazoalfa-era submodules) stays on `master`.

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Microsoft Visual Studio Solution File, Format Version 12.00
# Atmel Studio Solution File, Format Version 11.00
VisualStudioVersion = 14.0.23107.0
MinimumVisualStudioVersion = 10.0.40219.1
Project("{E66E83B9-2572-4076-B26E-6BE79FF3018A}") = "tsb_asm", "tsb_asm\tsb_asm.cppproj", "{6618D3BE-7EB3-49A2-9113-F128E396FF06}"
EndProject
Global
GlobalSection(SolutionConfigurationPlatforms) = preSolution
Debug|AVR = Debug|AVR
Release|AVR = Release|AVR
EndGlobalSection
GlobalSection(ProjectConfigurationPlatforms) = postSolution
{6618D3BE-7EB3-49A2-9113-F128E396FF06}.Debug|AVR.ActiveCfg = Debug|AVR
{6618D3BE-7EB3-49A2-9113-F128E396FF06}.Debug|AVR.Build.0 = Debug|AVR
{6618D3BE-7EB3-49A2-9113-F128E396FF06}.Release|AVR.ActiveCfg = Release|AVR
{6618D3BE-7EB3-49A2-9113-F128E396FF06}.Release|AVR.Build.0 = Release|AVR
EndGlobalSection
GlobalSection(SolutionProperties) = preSolution
HideSolutionNode = FALSE
EndGlobalSection
EndGlobal

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<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="14.0">
<PropertyGroup>
<SchemaVersion>2.0</SchemaVersion>
<ProjectVersion>7.0</ProjectVersion>
<ToolchainName>com.Atmel.AVRGCC8.CPP</ToolchainName>
<ProjectGuid>6618d3be-7eb3-49a2-9113-f128e396ff06</ProjectGuid>
<avrdevice>ATmega328P</avrdevice>
<avrdeviceseries>none</avrdeviceseries>
<OutputType>Executable</OutputType>
<Language>CPP</Language>
<OutputFileName>$(MSBuildProjectName)</OutputFileName>
<OutputFileExtension>.elf</OutputFileExtension>
<OutputDirectory>$(MSBuildProjectDirectory)\$(Configuration)</OutputDirectory>
<AssemblyName>tsb_asm</AssemblyName>
<Name>tsb_asm</Name>
<RootNamespace>tsb_asm</RootNamespace>
<ToolchainFlavour>avr-g++-16.1.0</ToolchainFlavour>
<KeepTimersRunning>true</KeepTimersRunning>
<OverrideVtor>false</OverrideVtor>
<CacheFlash>true</CacheFlash>
<ProgFlashFromRam>true</ProgFlashFromRam>
<RamSnippetAddress>0x20000000</RamSnippetAddress>
<UncachedRange />
<preserveEEPROM>true</preserveEEPROM>
<OverrideVtorValue>exception_table</OverrideVtorValue>
<BootSegment>2</BootSegment>
<ResetRule>0</ResetRule>
<eraseonlaunchrule>0</eraseonlaunchrule>
<EraseKey />
<AsfFrameworkConfig>
<framework-data xmlns="">
<options />
<configurations />
<files />
<documentation help="" />
<offline-documentation help="" />
<dependencies>
<content-extension eid="atmel.asf" uuidref="Atmel.ASF" version="3.52.0" />
</dependencies>
</framework-data>
</AsfFrameworkConfig>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
<ToolchainSettings>
<AvrGccCpp>
<avrgcc.common.Device>-mmcu=atmega328p</avrgcc.common.Device>
<avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
<avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
<avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
<avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
<avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
<avrgcccpp.compiler.symbols.DefSymbols>
<ListValues>
<Value>NDEBUG</Value>
</ListValues>
</avrgcccpp.compiler.symbols.DefSymbols>
<avrgcccpp.compiler.directories.IncludePaths>
<ListValues>
<Value>$(MSBuildProjectDirectory)\..\..\libavr\include</Value>
</ListValues>
</avrgcccpp.compiler.directories.IncludePaths>
<avrgcccpp.compiler.optimization.level>Optimize for size (-Os)</avrgcccpp.compiler.optimization.level>
<avrgcccpp.compiler.optimization.PrepareFunctionsForGarbageCollection>True</avrgcccpp.compiler.optimization.PrepareFunctionsForGarbageCollection>
<avrgcccpp.compiler.optimization.PrepareDataForGarbageCollection>True</avrgcccpp.compiler.optimization.PrepareDataForGarbageCollection>
<avrgcccpp.compiler.warnings.AllWarnings>True</avrgcccpp.compiler.warnings.AllWarnings>
<avrgcccpp.compiler.miscellaneous.OtherFlags>-std=c++26 -Wextra -Werror -mrelax -fno-exceptions -fno-rtti -fno-threadsafe-statics</avrgcccpp.compiler.miscellaneous.OtherFlags>
<avrgcccpp.linker.optimization.GarbageCollectUnusedSections>True</avrgcccpp.linker.optimization.GarbageCollectUnusedSections>
<avrgcccpp.linker.miscellaneous.LinkerFlags>-mrelax -nostartfiles -Wl,--section-start=.text=0x7e00 -Wl,--defsym=tsb_app=0 -Wl,--pmem-wrap-around=32k</avrgcccpp.linker.miscellaneous.LinkerFlags>
</AvrGccCpp>
</ToolchainSettings>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
<ToolchainSettings>
<AvrGccCpp>
<avrgcc.common.Device>-mmcu=atmega328p</avrgcc.common.Device>
<avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
<avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
<avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
<avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
<avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
<avrgcccpp.compiler.symbols.DefSymbols>
<ListValues>
<Value>DEBUG</Value>
</ListValues>
</avrgcccpp.compiler.symbols.DefSymbols>
<avrgcccpp.compiler.directories.IncludePaths>
<ListValues>
<Value>$(MSBuildProjectDirectory)\..\..\libavr\include</Value>
</ListValues>
</avrgcccpp.compiler.directories.IncludePaths>
<avrgcccpp.compiler.optimization.level>Optimize for size (-Os)</avrgcccpp.compiler.optimization.level>
<avrgcccpp.compiler.optimization.PrepareFunctionsForGarbageCollection>True</avrgcccpp.compiler.optimization.PrepareFunctionsForGarbageCollection>
<avrgcccpp.compiler.optimization.PrepareDataForGarbageCollection>True</avrgcccpp.compiler.optimization.PrepareDataForGarbageCollection>
<avrgcccpp.compiler.warnings.AllWarnings>True</avrgcccpp.compiler.warnings.AllWarnings>
<avrgcccpp.compiler.miscellaneous.OtherFlags>-std=c++26 -Wextra -Werror -mrelax -fno-exceptions -fno-rtti -fno-threadsafe-statics -gdwarf-4</avrgcccpp.compiler.miscellaneous.OtherFlags>
<avrgcccpp.linker.optimization.GarbageCollectUnusedSections>True</avrgcccpp.linker.optimization.GarbageCollectUnusedSections>
<avrgcccpp.linker.miscellaneous.LinkerFlags>-mrelax -nostartfiles -Wl,--section-start=.text=0x7e00 -Wl,--defsym=tsb_app=0 -Wl,--pmem-wrap-around=32k</avrgcccpp.linker.miscellaneous.LinkerFlags>
</AvrGccCpp>
</ToolchainSettings>
</PropertyGroup>
<ItemGroup>
<Compile Include="..\..\tsb\tsb_asm.cpp">
<SubType>compile</SubType>
<Link>tsb\tsb_asm.cpp</Link>
</Compile>
</ItemGroup>
<ItemGroup>
<Folder Include="tsb" />
</ItemGroup>
<Import Project="$(AVRSTUDIO_EXE_PATH)\Vs\Compiler.targets" />
</Project>

1
libavr Submodule

Submodule libavr added at 93d8b0e491

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# Oracle — the hand-written TinySafeBoot assembly
`tsb-fixedbaud.asm` is the reference implementation this port is measured
against: the **native-UART, fixed-baud** TinySafeBoot bootloader, hand-written
in AVR assembly. It is the size-and-feature bar for the port's `tsb_asm` tier.
- **Source**: <https://github.com/seedrobotics/tinysafeboot>
(`firmware_ASM/latest_stable_release/20200727-fixedbaud/main.asm`), the Seed
Robotics fixed-baud fork of Julien Thomas' TinySafeBoot.
- **License**: GPLv3 (see the header in the file). It is vendored here **only as
a reference oracle** — it is not compiled, linked, or distributed as part of
the MIT-licensed port. Mere aggregation.
## Why this variant
The user chose the fixed-baud, hardware-UART variant deliberately: it is the one
whose feature set the port must match. It fits the **complete** TSB feature set
into the 512-byte ATmega boot section:
| Feature | Oracle routine |
|---|---|
| Watchdog-reset bail straight to the app | `RESET` (WDRF check) |
| One-wire half-duplex (RX/TX shorted): RXEN/TXEN toggled per direction, TX turnaround guard | `SetRX` / `SetTX` / `TransmitByte` |
| Activation timeout read from the config page, with a lockout-proof minimum | `WRX1To` (uses `utimeoutH`) |
| 3×`@` activation knock | `ActCharRcvd` |
| Password gate; wrong byte hangs (still draining the UART) | `CheckPassword` |
| Emergency erase on password `\0` + double-confirm — wipes flash, EEPROM and the config page | `EmergencyErase` |
| Device-info block (16 bytes) | `SendDeviceInfo` / `DEVICEINFO` |
| App-flash read/write (`f`/`F`), EEPROM read/write (`e`/`E`), config read/write (`c`/`C`) | `CheckCommands` |
## Assembled size (the bar)
Assembled for the ATmega328P with `avra`:
```
avra -I /usr/share/avra tsb-fixedbaud.asm # after uncommenting .include "m328Pdef.inc"
# Code : 250 words (500 bytes) — the whole loader, all features, in the 512 B section
```
**500 bytes with every feature** — the proof that ≤512 B and full feature parity
are simultaneously reachable. The port's four tiers reach it from the other
side, and the gradient between them is the cost of the mechanisms each is
allowed:
| tier | bytes | section | what it is allowed |
|---|---|---|---|
| oracle | 500 | 512 B | hand-written assembly, the reference |
| `tsb_asm` | 512 | 512 B | C++ on libavr, two routines in asm |
| `tsb_tricks` | 528 | 1 KB | no asm; global register variables |
| `tsb_policy` | 630 | 1 KB | pureboot's rules: no asm, no register variables |
| `tsb_pure` | 776 | 1 KB | idiomatic libavr throughout |
The two routines `tsb_asm` keeps are the ones whose remaining cost is the
calling convention itself: the bounded rx and the page-store loop. It fills
its section exactly, with the same one-bit-time turn-around guard the oracle
spends six bytes on - every tier implements the whole feature set, which is
what makes the column a gradient rather than four different loaders.
The oracle targets 20 MHz / 33333 baud; the port targets 16 MHz / 115200 baud
(what the simavr protocol test drives). Baud and geometry differ, code size and
feature set do not.

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;***********************************************************************
;***********************************************************************
;***********************************************************************
; TinySafeBoot - The Universal Bootloader for AVR ATmegas
;***********************************************************************
;***********************************************************************
;***********************************************************************
;
;-----------------------------------------------------------------------
; 2020 - Version using native UART, Fixed Baud by Seed Robotics in 2020
;-----------------------------------------------------------------------
; meant for use on ATMEGA devices only (with native UART - UART0)
;
; Main differences to Regular TSB Bootloader:
; - Uses a native UART (UART0); therefore not compatible with ATTINY
; - Baud rate is fixed (set by a macro in the code). No auto bauding.
; - Disables TX while not transmitting to allow for one wire flashing
; (where RX and TX are shorted, for a multi drop bus)
; - Also works with separate RX and TX; however an external pull up
; on TX _may_ be required; alternatively you can modify the code
; in the ReceiveByte routine so that it won't disable TX.
; - FIXES:
; - situations where booting onto a bus with active communication could
; lock the autobauding feature
; - times out and boots to application code if the host stops interacting
; with the bootloader
;
;-----------------------------------------------------------------------
; Extended by Seed Robotics from 2017
;-----------------------------------------------------------------------
; Seed Robotics contributions are available from the Github
; repository github.com/seedrobotics
; The License and conditions remain as stated below, in the
; original notice.
;
;
;-----------------------------------------------------------------------
; Written in 2011-2015 by Julien Thomas
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation; either version 3
; of the License, or (at your option) any later version.
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty
; of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
; See the GNU General Public License for more details.
; You should have received a copy of the GNU General Public License
; along with this program; if not, see:
; http://www.gnu.org/licenses/
;-----------------------------------------------------------------------
;
;
;
;***********************************************************************
; OVERVIEW
;***********************************************************************
;
; TSB assembly source is organized in 4 segments (approx. line numbers)
;
; ~ 50 ... Global definitions
; ~ ... TSB for ATmegas
;
;***********************************************************************
; ADJUSTMENTS FOR INDIVIDUAL ASSEMBLY
;***********************************************************************
;
; This Sourcecode is directly compatible to: AVRASM2, GAVRASM
;
.nolist
;
;-----------------------------------------------------------------------
; SPECIFY TARGET AVR
;-----------------------------------------------------------------------
;
; Comment in and provide def.inc file for target device
;
; [Examples]
;
;.include "tn2313def.inc"
;.include "tn85def.inc"
;.include "m8515def.inc"
;.include "m168def.inc"
;.include "m161def.inc"
;.include "m324Adef.inc"
;.include "m328Pdef.inc"
;.include "tn441def.inc"
;.include "tn167def.inc"
;.include "tn861def.inc"
;.include "tn841def.inc"
;.include "tn84def.inc"
;.include "m8def.inc"
;.include "m644PAdef.inc"
;.include "m644def.inc"
;.include "tn167def.inc"
;.include "tn25def.inc"
;
; [...]
;
;
.list
;
;-----------------------------------------------------------------------
; BUILD INFO
;-----------------------------------------------------------------------
; YY = Year - MM = Month - DD = Day
.set YY = 21
.set MM = 12
.set DD = 21
;
.set BUILDSTATE = $F3 ; F1 fixed baud, pull up, derived from original (modified for fixed baud)
; F2 fixed baud, pull up, guaranteed minimum activation timeout in case of userpage data corruption
; F3 adds a CONSTANT with clock speed (Mhz) as word in the last page of memory (clock speed our defined CONSTANT)
;
;-----------------------------------------------------------------------
; TSB / TSB-INSTALLER SWITCH
;-----------------------------------------------------------------------
; 0 = Regular assembly to target address
; Other value = NOT SUPPORTED
;
.set TSBINSTALLER = 0
;
;-----------------------------------------------------------------------
; F_CPU and Baud rate setting
;-----------------------------------------------------------------------
.equ F_CPU = 20000000
.equ BAUD = 33333 ; baudrate (notice some possible wrong cals: example for 56K, it is actually 55,555, so for BAUD_PRESC give an INT result of 8, we must set BAUD to 55500)
.equ BAUD_PRESCx10 = (F_CPU * 10/16/BAUD) - 10 ; baud prescale (regular formula = F_CPU * 10/16/BAUD - 1 but we do it x10 to check the rounding)
; arredondar acima se necesssario
.if BAUD_PRESCx10 - ( (BAUD_PRESCx10 / 10) * 10 ) >= 5 ; calculate the remainder: we rely on the fact these are integer divisions. Therefore, dividing by 10, rounds DOWN in integer division
.equ BAUD_PRESC = (F_CPU/16/BAUD)
.warning "Incrementing default BAUD_PRESC formula by 1 due to rounding."
.else
.equ BAUD_PRESC = (F_CPU/16/BAUD) - 1
.warning "Using default BAUD_PRESC formula (no rounding up)"
.endif
.if BAUD_PRESC > 255
.error "ERROR: BAUD RATE TOO LOW. WE ONLY WRITE THE UBRRL REGISTER, SO UBRR MUST BE <255 FOR THIS CLOCK FREQ AND BAUD"
.endif
;***********************************************************************
; AUTO-ADJUST FOR DIFFERENT ASSEMBLY OPTIONS
;***********************************************************************
;
; Always set TINYMEGA=1 bc this code only supports ATMEGA
.equ TINYMEGA=1
.if FLASHEND > ($7fff)
.error "SORRY! DEVICES OVER 64 KB NOT SUPPORTED YET."
.exit
.endif
;-----------------------------------------------------------------------
; Workarounds for devices with renamed or missing definitions
;-----------------------------------------------------------------------
;
.ifndef SPMCSR ; SPMEN / PGERS / ...
.equ SPMCSR = SPMCR
.endif
.ifndef MCUSR ; PORF / EXTRF / BORF / WDRF
.equ MCUSR = MCUCSR
.endif
; Detect Attiny441/841 to amend missing pagesize and apply 4-page mode
.set FOURPAGES = 0
.if ((SIGNATURE_000 == $1E) && (SIGNATURE_002 == $15) && (SIGNATURE_001 == $92))
.equ PAGESIZE = 32
.set FOURPAGES = 1
.message "ATTINY441: 4-PAGE-ERASE MODE"
.endif
.if ((SIGNATURE_000 == $1E) && (SIGNATURE_002 == $15) && (SIGNATURE_001 == $93))
.equ PAGESIZE = 32
.set FOURPAGES = 1
.message "ATTINY841: 4-PAGE-ERASE MODE"
.endif
;-----------------------------------------------------------------------
; Universal Constants and Registers
;-----------------------------------------------------------------------
.equ REQUEST = '?' ; request / answer / go on
.equ CONFIRM = '!' ; confirm / attention
; Current bootloader date coded into 16-bit number
.equ BUILDDATE = YY * 512 + MM * 32 + DD
; Other
.equ INFOLEN = 8 ; *Words* of Device Info
.equ BUFFER = SRAM_START
; Registers (in use by TSB-Firmware and TSB-Installer for ATtinys)
.def avecl = r4 ; application vector temp low
.def avech = r5 ; application vector temp high
.def tmp1 = r16 ; these are
.def tmp2 = r17 ; universal
.def tmp3 = r18 ; temporary
.def tmp4 = r19 ; registers
.def bcnt = r20 ; page bytecounter
.def cntr1 = r21 ; timeout counter
.def rxen = r22 ; check if RX enabled (meaning TX disabled)
.def utimeoutH = r23 ; user timeout High byte
; special purpose registers start at R26
;
;
;***********************************************************************
;***********************************************************************
;***********************************************************************
; START OF TSB FOR ATMEGAS
;***********************************************************************
;***********************************************************************
;***********************************************************************
;
; TSB for ATmegas is always coded directly to target address.
.if TINYMEGA == 1
.message "ASSEMBLY OF TSB FOR ATMEGA"
.equ BOOTSTART = (FLASHEND+1)-256 ; = 512 Bytes
.equ LASTPAGE = BOOTSTART - PAGESIZE ; = 1 page below TSB!
.org BOOTSTART
RESET:
cli
in tmp4, MCUSR ; check reset condition
sbrc tmp4, WDRF ; in case of a Watchdog reset
rjmp APPJUMP ; immediately leave TSB
ldi tmp1, low (RAMEND) ; write ramend low
out SPL, tmp1 ; into SPL (stackpointer low)
.ifdef SPH
ldi tmp1, high(RAMEND) ; write ramend high for ATtinys
out SPH, tmp1 ; with SRAM > 256 bytes
.message "PROVIDING FOR STACK BIGGER THAN 256 BYTES"
.endif
.ifndef DDRD2
.equ DDRD2 = DDD2
.endif
;-----------------------------------------------------------------------
; ACTIVATION CHECK
;-----------------------------------------------------------------------
; Configure UART; no autobauding in this version
ldi tmp1,BAUD_PRESC ; load baud prescale
sts UBRR0L,tmp1 ; set baud prescale
; ldi tmp2,HIGH(bpsc) ; save code by not loading UBBRH
;sts UBRRH,tmp2 ; to UBRR0
;ldi tmp2,( (1<<RXEN0) ) ; enable transmiter and receiver
;sts UCSR0B,tmp2
; Enable Pull up on Port D2 (PD2)
cbi DDRD, DDRD2
sbi PORTD, PORTD2
; we will enable RNEN/TXEN in the ReceiveByte and TransmitByte routines
rcall ZtoLASTPAGE ; set Z to start'o'LASTPAGE
adiw zl, 2 ; skip first 2 bytes (APPJUMP)
lpm utimeoutH, z+ ; load TIMEOUT byte and store for use in RX byte timeout
ori utimeoutH, (F_CPU / 1000000); prevent bootloader lockout due if it gets an invalid (to small) timeout setting
; this ensures value is at least the clock rate, which shoudl give about 40ms
clr tmp2 ; apparently at times this is not set to 0 on boot? (seen while in debugWire)
clr rxen ; same as above
WRX1To:
; we'll check the X register which is where ReceibeByte controls the timeout
; the overall timeout of receive byte is the timeout set by the user
; therefore, if we get characters while X> 0 we're attempting to activate bootloader;
; if not, if X=0 we timedout and go to app start
rcall ReceiveByte
brcs WRX2To ; if X got to 0 (i.e. carry set), assume we timed out
cpi tmp1, '@' ; did we get an activation char = "@"
breq ActCharRcvd
WRX2To:
rjmp APPJUMP ; not an activation char goto APPJUMP in LASTPAGE
ActCharRcvd:
inc tmp2
cpi tmp2, 3
brne WRX1To ; branch if not yet at 3;
; otherwise fall through to password check
;-----------------------------------------------------------------------
; CHECK PASSWORD / EMERGENCY ERASE
;-----------------------------------------------------------------------
; we use the user timeout (utimeoutH) register for COMM timeout
; when we don't get valid data
; increase this value to a fixed one now, to cope
; with cases where the user timeout is set so low that we don't have time to
; do anything
ldi utimeoutH, (F_CPU / 78500) ; this should result in 255 for 20Mhz and proportionally
; less for lower Clocks, so that we get the same time approx. 2.4sec
CheckPassword:
chpw0: ser tmp4 ; tmp4 = 255 enables comparison
chpw1: lpm tmp3, z+ ; load pw character from Z
and tmp3, tmp4 ; if tmp4 = 0 disables comparison, for wrong password scenarios
cpi tmp3, 255 ; byte value 255 indicates
breq chpwx ; end of password -> success
chpw2: rcall Receivebyte ; else receive next character
cpi tmp1, 0 ; rxbyte = 0 will branch
breq chpwee ; to confirm emergency erase
cp tmp1, tmp3 ; compare password with rxbyte
breq chpw0 ; if equal check next character
clr tmp4 ; tmp4 = 0 to loop forever
rjmp chpw1 ; and smoothen power profile
chpwee:
; Fix for ISSUE #1: only check for Emergency Erase if we haven't
; gotten a wrong password; if we got a wrong password
; then we should stay in loop and not escape to Emergency
; Erase
cpi tmp4, 0 ; if tmp4=0 we are set to loop forever
breq chpw1
rcall RequestConfirm ; request confirm
brts chpa ; not confirmed, leave
rcall RequestConfirm ; request 2nd confirm
brts chpa ; can't be mistake now
rcall EmergencyErase ; go, emergency erase!
rjmp Mainloop
chpa:
rjmp APPJUMP ; start application
chpwx:
; rjmp SendDeviceInfo ; go on to SendDeviceInfo
;-----------------------------------------------------------------------
; SEND DEVICEINFO
;-----------------------------------------------------------------------
SendDeviceInfo:
ldi zl, low (DEVICEINFO*2) ; load address of deviceinfo
ldi zh, high(DEVICEINFO*2) ; low and highbyte
ldi bcnt, INFOLEN*2
rcall SendFromFlash
;-----------------------------------------------------------------------
; MAIN LOOP TO RECEIVE AND EXECUTE COMMANDS
;-----------------------------------------------------------------------
Mainloop:
clr zl ; clear Z pointer
clr zh ; which is frequently used
rcall SendConfirm ; send CONFIRM via RS232
rcall Receivebyte ; receive command via RS232
rcall CheckCommands ; check command letter
rjmp Mainloop ; and loop on
;-----------------------------------------------------------------------
; CHANGE USER DATA IN LASTPAGE
;-----------------------------------------------------------------------
ChangeSettings:
rcall GetNewPage ; get new LASTPAGE contents
brtc ChangeS0 ; from Host (if confirmed)
ret
ChangeS0:
rcall ZtoLASTPAGE ; re-write LASTPAGE
rcall EraseFlashPage
rcall WritePage ; erase and write LASTPAGE
;-----------------------------------------------------------------------
; SEND USER DATA FROM LASTPAGE
;-----------------------------------------------------------------------
ControlSettings:
rcall ZtoLASTPAGE ; point to LASTPAGE
; rcall SendPageFromFlash
;-----------------------------------------------------------------------
; SEND DATA FROM FLASH MEMORY
;-----------------------------------------------------------------------
SendPageFromFlash:
ldi bcnt, low (PAGESIZE*2) ; whole Page to send
SendFromFlash:
rcall SPMwait ; (re)enable RWW read access
lpm tmp1, z+ ; read directly from flash
rcall Transmitbyte ; and send out to RS232
dec bcnt ; bcnt is number of bytes
brne SendFromFlash
ret
;-----------------------------------------------------------------------
; READ APPLICATION FLASH
;-----------------------------------------------------------------------
; read and transmit application flash area (pagewise)
ReadAppFlash:
RAF0:
rcall RwaitConfirm
brts RAFx
rcall SendPageFromFlash
RAF1:
cpi zl, low (LASTPAGE*2) ; count up to last byte
brne RAF0 ; below LASTPAGE
cpi zh, high(LASTPAGE*2)
brne RAF0
RAFx:
ret
;-----------------------------------------------------------------------
; WRITE APPLICATION FLASH
;-----------------------------------------------------------------------
; Write Appflash pagewise, don't modify anything for ATmegas
WriteAppFlash:
rcall EraseAppFlash ; Erase whole app flash
Flash2:
rcall GetNewPage ; get next page from host
brts FlashX ; stop on user's behalf
Flash3:
rcall WritePage ; write page data into flash
Flash4:
cpi zh, high(LASTPAGE*2-1) ; end of available Appflash?
brne Flash2 ; if Z reached last location
cpi zl, low (LASTPAGE*2-1) ; then we are finished
brne Flash2 ; else go on
FlashX:
ret ; we're already finished!
;-----------------------------------------------------------------------
; WRITE FLASH PAGE FROM BUFFER, VERIFYING AND VERIFY-ERROR-HANDLING
;-----------------------------------------------------------------------
WritePage:
rcall YtoBUFFER ; Y=BUFFER, bcnt=PAGESIZE*2
WrPa1:
ld r0, y+ ; fill R0/R1 with word
ld r1, y+ ; from buffer position Y / Y+1
ldi tmp1, 0b00000001 ; set only SPMEN in SPMCSR
out SPMCSR, tmp1 ; to activate page buffering
spm ; store word in page buffer
adiw zl, 2 ; and forward to next word
subi bcnt, 2
brne WrPa1
; Z = start of next page now
subi zl, low (PAGESIZE*2) ; point back Z to
sbci zh, high(PAGESIZE*2) ; start of current page
; Z = back on current page's start
WrPa2:
ldi tmp1, 0b00000101 ; enable PRWRT + SPMEN
out SPMCSR, tmp1 ; in SPMCSR
spm ; write whole page to flash
WrPa3:
in tmp1, SPMCSR ; wait for flash write finished
sbrc tmp1, 0 ; skip if SPMEN (bit0) cleared
rjmp WrPa3 ; ITS BEEN WRITTEN
subi zl, low (-PAGESIZE*2) ; same effect as
sbci zh, high(-PAGESIZE*2) ; Z = Z + PAGESIZE*2
ret
;-----------------------------------------------------------------------
; CHECK COMMANDS
;-----------------------------------------------------------------------
CheckCommands:
cpi tmp1, 'c' ; read LASTPAGE
breq ControlSettings
cpi tmp1, 'C' ; write LASTPAGE
breq ChangeSettings
cpi tmp1, 'f' ; read Appflash
breq ReadAppFlash
cpi tmp1, 'F' ; write Appflash
breq WriteAppFlash
cpi tmp1, 'e' ; read EEPROM
breq EepromRead
cpi tmp1, 'E' ; write EEPROM
breq EEpromWrite
rjmp APPJUMP ; else start application
;-----------------------------------------------------------------------
; EEPROM READ/WRITE ACCESS
;-----------------------------------------------------------------------
EepromWrite:
EEWr0:
rcall GetNewPage ; get EEPROM datablock
brts EERWFx ; or abort on host's demand
EEWr1:
rcall YtoBUFFER ; Y = Buffer and Bcnt = blocksize
EEWr2:
ld tmp1, y+ ; read EEPROM byte from buffer
rcall EEWriteByte
dec bcnt ; count down block byte counter
brne EEWr2 ; loop on if block not finished
rjmp EeWr0
;-----------------------------------------------------------------------
EEpromRead:
EeRe1:
rcall RwaitConfirm ; wait to confirm
brts EERWFx ; else we are finished
ldi bcnt, low(PAGESIZE*2) ; again PAGESIZE*2 is blocksize
EERe2:
out EEARL, zl ; current EEPROM address low
.ifdef EEARH
out EEARH, zh ; current EEPROM address high
.endif
sbi EECR, 0 ; set EERE - EEPROM read enable
in tmp1, EEDR ; read byte from current address
rcall Transmitbyte ; send out to RS232
adiw zl,1 ; count up EEPROM address
dec bcnt ; count down block byte counter
brne EERe2 ; loop on if block not finished
rjmp EERe1
EERWFx:
ret
;-----------------------------------------------------------------------
EEWriteByte:
out EEDR, tmp1 ; write to EEPROM data register
out EEARL, zl ; current EEPROM address low
.ifdef EEARH
out EEARH, zh ; high EEARH for some attinys
.endif
sbi EECR, 2 ; EEPROM master prog enable
sbi EECR, 1 ; EEPE initiate prog cycle
EeWB:
sbic EECR, 1 ; wait write cycle to complete
rjmp EeWB ; before we can go on
adiw zl,1 ; count up EEPROM address
ret
;-----------------------------------------------------------------------
; GET NEW PAGE
;-----------------------------------------------------------------------
GetNewPage:
rcall RequestConfirm ; check for Confirm
brts GNPx ; abort if not confirmed
GNP0:
rcall YtoBUFFER ; Y = BUFFER, bcnt = PAGESIZE*2
GNP1:
rcall ReceiveByte ; receive serial byte
st y+, tmp1 ; and store in buffer
dec bcnt ; until full page loaded
brne GNP1 ; loop on
GNPx:
ret ; finished
;-----------------------------------------------------------------------
; REQUEST TO CONFIRM / AWAIT CONFIRM COMMAND
;-----------------------------------------------------------------------
RequestConfirm:
ldi tmp1, REQUEST ; send request character
rcall Transmitbyte ; prompt to confirm (or not)
RwaitConfirm:
rcall ReceiveByte ; get host's reply
clt ; set T=0 for confirmation
cpi tmp1, CONFIRM ; if host HAS sent CONFIRM
breq RCx ; return with the T=0
set ; else set T=1 (NOT CONFIRMED)
RCx:
ret ; whether confirmed or not
;-----------------------------------------------------------------------
; FLASH ERASE TOP-TO-BOTTOM ( (BOOTSTART-1) ... $0000)
;-----------------------------------------------------------------------
EraseAppFlash:
rcall ZtoLASTPAGE ; point Z to LASTPAGE, directly
EAF0:
subi zl, low (PAGESIZE*2)
sbci zh, high(PAGESIZE*2)
rcall EraseFlashPage
brne EAF0 ; until first page reached
EAFx: ret ; and leave with Z = $0000
;-----------------------------------------------------------------------
; EMERGENCY ERASE OF FLASH / EEPROM / USERDATA
;-----------------------------------------------------------------------
EmergencyErase:
rcall EraseAppFlash ; erase Application Flash
ser tmp1 ; byte value for EEPROM writes
EEE0:
rcall EEWriteByte ; write EEPROM byte, Z = Z + 1
cpi zh, high(EEPROMEND+1)+2 ; EEPROMEND
brne EEE0 ; and loop on until finished
rcall ZtoLASTPAGE ; LASTPAGE is to be erased
; rcall EraseFlashPage
;-----------------------------------------------------------------------
; ERASE ONE FLASH PAGE
;-----------------------------------------------------------------------
EraseFlashPage:
ldi tmp1, 0b00000011 ; enable PGERS + SPMEN
out SPMCSR, tmp1 ; in SPMCSR and erase current
spm ; page by SPM (MCU halted)
; Waiting for SPM to be finished is *obligatory* on ATmegas!
SPMwait:
in tmp1, SPMCSR
sbrc tmp1, 0 ; wait previous SPMEN
rjmp SPMwait
ldi tmp1, 0b00010001 ; set RWWSRE and SPMEN
out SPMCSR, tmp1
spm
ret
;-----------------------------------------------------------------------
; OTHER SUBROUTINES
;-----------------------------------------------------------------------
YtoBUFFER:
ldi yl, low (BUFFER) ; reset pointer
ldi yh, high(BUFFER) ; to programming buffer
ldi bcnt, low(PAGESIZE*2) ; and often needed
ret
;-----------------------------------------------------------------------
ZtoLASTPAGE:
ldi zl, low (LASTPAGE*2) ; reset Z to LASTPAGE start
ldi zh, high(LASTPAGE*2)
ret
;-----------------------------------------------------------------------
; RS232 RECEIVE BYTE
;-----------------------------------------------------------------------
; uses: tmp1 (received data byte), cntr1 (for timeout)
; also uses utimeoutH which holds the default timeout defined by the user
; and X which is actually used to count down
SetRX:
ldi tmp1,(1<<RXEN0) ; enable receiver (Transmitter disabled)
sts UCSR0B,tmp1
ser rxen
ReceiveByte:
sbrs rxen, 0
rjmp SetRX
; outer counter
mov xh, utimeoutH
;ldi xl, 128
ReceiveByteShortTimeout:
ser cntr1 ; inner counter reset
ReceiveByteShortTimeout1:
lds tmp1, UCSR0A ; load UART status register A
sbrc tmp1, RXC0 ; if not RXComplete, skip
rjmp LoadRXByte
dec cntr1 ; if counter not zero
brne ReceiveByteShortTimeout1 ; cycle again; else fall through
sbiw xl, 1 ; dec outter counter
brcc ReceiveByteShortTimeout ; continue of outter counetr still active
;ret ;
LoadRXByte:
lds tmp1, UDR0 ; load received character even if RXC is not set
ret ; (it loads 0 and UDR FIFO should recover for next char)
;-----------------------------------------------------------------------
; RS232 SEND CONFIRM CHARACTER
;-----------------------------------------------------------------------
SendConfirm:
ldi tmp1, CONFIRM
rjmp Transmitbyte
;-----------------------------------------------------------------------
; RS232 TRANSMIT BYTE
;-----------------------------------------------------------------------
; uses: tmp1 (transmit byte will be shifted out), tmp2 (bitcounter)
;
SetTX:
ldi tmp2,(1<<TXEN0) ; enable transmitter (Receiver disabled)
sts UCSR0B,tmp2
clr rxen
; wait some guard time to allow receiving devices ot transition
; from TX t RX state
ser cntr1 ; inner counter reset
SetTXShortTimeout:
nop
dec cntr1 ; if counter not zero
brne SetTXShortTimeout ; cycle again; else fall through
TransmitByte:
sbrc rxen, 0
rjmp SetTX
; no need to wait for UDRE bc we will wait for TXC on
; every char transmitted. TXC occurs later that UDRE
; so UDRE should be asserted when TXC asserts
sts UDR0, tmp1
WaitForTXC:
lds tmp2, UCSR0A ; wait for TXC (and not UDRE)
sbrs tmp2, TXC0 ; bc after this char we may transition
rjmp WaitForTXC ; to receiving chars and we want to make sure we get a clean transition
; we need to write a 1 to clear the TXC flag; otherwise the flag won't clear
sts UCSR0A, tmp2 ; tmp2 should contain an asserted TXC bit
ret
;-----------------------------------------------------------------------
; ATMEGA APPJUMP = SIMPLE JUMP TO $0000 (ORIGINAL RESET VECTOR)
;-----------------------------------------------------------------------
; Boot Reset Vector (BOOTRST) must be activated for TSB on ATmegas.
; After timeout or executing commands, TSB for ATmegas will simply
; handover to the App by a (relative or absolute) jump to $0000.
APPJUMP:
rcall SPMwait ; make sure everything's done
.if FLASHEND >= ($1fff)
jmp $0000 ; absolute jump
.else
rjmp $0000 ; relative jump
.endif
DEVICEINFO:
.message "DEVICE INFO BLOCK FOR ATMEGA"
.db "TSB", low (BUILDDATE), high (BUILDDATE), BUILDSTATE
.db SIGNATURE_000, SIGNATURE_001, SIGNATURE_002, low (PAGESIZE)
.dw BOOTSTART-PAGESIZE
.dw EEPROMEND
.db $AA, $AA
;-----------------------------------------------------------------------
; DEVICE INFO BLOCK = PERMANENT DATA
;-----------------------------------------------------------------------
; set last word with the clock speed
.org FLASHEND
.dw (F_CPU/1000000)
//.message "SAVING CLOCK SPEED IN LAST BYTE AS " (F_CPU/1000000) " Mhz"
.message "ASSEMBLY OF TSB FOR ATMEGA SUCCESSFULLY FINISHED!"
.endif ; closing TSB for ATmega sourcecode;
;***********************************************************************
; END OF TSB FOR ATMEGAS
;***********************************************************************
.exit
;***********************************************************************
;***********************************************************************
;***********************************************************************
; END OF CONDITIONAL ASSEMBLY SOURCE OF TSB FOR ATTINYS AND ATMEGAS
;***********************************************************************
;***********************************************************************
;***********************************************************************

4
stk500v2/clock.hpp
View File

@@ -1,4 +0,0 @@
#pragma once
#define F_CPU 18'432'000
#include <util/delay.h>

113
stk500v2/command.hpp
View File

@@ -1,113 +0,0 @@
#pragma once
#include <stdint.h>
//////////////////////////////////////////////////////////////////////////
// STK message constants
static constexpr uint8_t MESSAGE_START = 0x1B; // ASCII ESC
static constexpr uint8_t TOKEN = 0x0E;
//////////////////////////////////////////////////////////////////////////
// STK general command constants
static constexpr uint8_t CMD_SIGN_ON = 0x01;
static constexpr uint8_t CMD_SET_PARAMETER = 0x02;
static constexpr uint8_t CMD_GET_PARAMETER = 0x03;
static constexpr uint8_t CMD_SET_DEVICE_PARAMETERS = 0x04;
static constexpr uint8_t CMD_OSCCAL = 0x05;
static constexpr uint8_t CMD_LOAD_ADDRESS = 0x06;
static constexpr uint8_t CMD_FIRMWARE_UPGRADE = 0x07;
//////////////////////////////////////////////////////////////////////////
// STK ISP command constants
static constexpr uint8_t CMD_ENTER_PROGMODE_ISP = 0x10;
static constexpr uint8_t CMD_LEAVE_PROGMODE_ISP = 0x11;
static constexpr uint8_t CMD_CHIP_ERASE_ISP = 0x12;
static constexpr uint8_t CMD_PROGRAM_FLASH_ISP = 0x13;
static constexpr uint8_t CMD_READ_FLASH_ISP = 0x14;
static constexpr uint8_t CMD_PROGRAM_EEPROM_ISP = 0x15;
static constexpr uint8_t CMD_READ_EEPROM_ISP = 0x16;
static constexpr uint8_t CMD_PROGRAM_FUSE_ISP = 0x17;
static constexpr uint8_t CMD_READ_FUSE_ISP = 0x18;
static constexpr uint8_t CMD_PROGRAM_LOCK_ISP = 0x19;
static constexpr uint8_t CMD_READ_LOCK_ISP = 0x1A;
static constexpr uint8_t CMD_READ_SIGNATURE_ISP = 0x1B;
static constexpr uint8_t CMD_READ_OSCCAL_ISP = 0x1C;
static constexpr uint8_t CMD_SPI_MULTI = 0x1D;
//////////////////////////////////////////////////////////////////////////
// STK PP command constants
static constexpr uint8_t CMD_ENTER_PROGMODE_PP = 0x20;
static constexpr uint8_t CMD_LEAVE_PROGMODE_PP = 0x21;
static constexpr uint8_t CMD_CHIP_ERASE_PP = 0x22;
static constexpr uint8_t CMD_PROGRAM_FLASH_PP = 0x23;
static constexpr uint8_t CMD_READ_FLASH_PP = 0x24;
static constexpr uint8_t CMD_PROGRAM_EEPROM_PP = 0x25;
static constexpr uint8_t CMD_READ_EEPROM_PP = 0x26;
static constexpr uint8_t CMD_PROGRAM_FUSE_PP = 0x27;
static constexpr uint8_t CMD_READ_FUSE_PP = 0x28;
static constexpr uint8_t CMD_PROGRAM_LOCK_PP = 0x29;
static constexpr uint8_t CMD_READ_LOCK_PP = 0x2A;
static constexpr uint8_t CMD_READ_SIGNATURE_PP = 0x2B;
static constexpr uint8_t CMD_READ_OSCCAL_PP = 0x2C;
static constexpr uint8_t CMD_SET_CONTROL_STACK = 0x2D;
//////////////////////////////////////////////////////////////////////////
// STK HVSP command constants
static constexpr uint8_t CMD_ENTER_PROGMODE_HVSP = 0x30;
static constexpr uint8_t CMD_LEAVE_PROGMODE_HVSP = 0x31;
static constexpr uint8_t CMD_CHIP_ERASE_HVSP = 0x32;
static constexpr uint8_t CMD_PROGRAM_FLASH_HVSP = 0x33;
static constexpr uint8_t CMD_READ_FLASH_HVSP = 0x34;
static constexpr uint8_t CMD_PROGRAM_EEPROM_HVSP = 0x35;
static constexpr uint8_t CMD_READ_EEPROM_HVSP = 0x36;
static constexpr uint8_t CMD_PROGRAM_FUSE_HVSP = 0x37;
static constexpr uint8_t CMD_READ_FUSE_HVSP = 0x38;
static constexpr uint8_t CMD_PROGRAM_LOCK_HVSP = 0x39;
static constexpr uint8_t CMD_READ_LOCK_HVSP = 0x3A;
static constexpr uint8_t CMD_READ_SIGNATURE_HVSP = 0x3B;
static constexpr uint8_t CMD_READ_OSCCAL_HVSP = 0x3C;
//////////////////////////////////////////////////////////////////////////
// STK status constants
// Success
static constexpr uint8_t STATUS_CMD_OK = 0x00;
// Warnings
static constexpr uint8_t STATUS_CMD_TOUT = 0x80;
static constexpr uint8_t STATUS_RDY_BSY_TOUT = 0x81;
static constexpr uint8_t STATUS_SET_PARAM_MISSING = 0x82;
// Errors
static constexpr uint8_t STATUS_CMD_FAILED = 0xC0;
static constexpr uint8_t STATUS_CKSUM_ERROR = 0xC1;
static constexpr uint8_t STATUS_CMD_UNKNOWN = 0xC9;
//////////////////////////////////////////////////////////////////////////
// STK parameter constants
static constexpr uint8_t PARAM_BUILD_NUMBER_LOW = 0x80;
static constexpr uint8_t PARAM_BUILD_NUMBER_HIGH = 0x81;
static constexpr uint8_t PARAM_HW_VER = 0x90;
static constexpr uint8_t PARAM_SW_MAJOR = 0x91;
static constexpr uint8_t PARAM_SW_MINOR = 0x92;
static constexpr uint8_t PARAM_VTARGET = 0x94;
static constexpr uint8_t PARAM_VADJUST = 0x95;
static constexpr uint8_t PARAM_OSC_PSCALE = 0x96;
static constexpr uint8_t PARAM_OSC_CMATCH = 0x97;
static constexpr uint8_t PARAM_SCK_DURATION = 0x98;
static constexpr uint8_t PARAM_TOPCARD_DETECT = 0x9A;
static constexpr uint8_t PARAM_STATUS = 0x9C;
static constexpr uint8_t PARAM_DATA = 0x9D;
static constexpr uint8_t PARAM_RESET_POLARITY = 0x9E;
static constexpr uint8_t PARAM_CONTROLLER_INIT = 0x9F;
//////////////////////////////////////////////////////////////////////////
// STK answer constants
static constexpr uint8_t ANSWER_CKSUM_ERROR = 0xB0;

1
stk500v2/flash

Submodule stk500v2/flash deleted from 6edb2e5a21

1
stk500v2/io

Submodule stk500v2/io deleted from 80de36ee7e

571
stk500v2/main.cpp
View File

@@ -1,571 +0,0 @@
#include "clock.hpp"
#include "uart/uart.hpp"
#include <avr/boot.h>
#include <avr/interrupt.h>
#include <avr/io.h>
#include <avr/pgmspace.h>
#include "command.hpp"
using uart_interface = uart::Hardware0<uart::Config<115200>, uart::Driven::BLOCKING>;
uart::Uart<uart_interface> serial;
struct Message {
uint8_t start;
uint8_t number;
uint16_t size;
uint8_t token;
uint8_t body[275];
uint8_t checksum;
};
static inline bool receiveByte(uint8_t &data, uint32_t timeout = 100000)
{
for (uint32_t i = 0; i < timeout; ++i) {
if (serial.rxByte(data))
return true;
}
return false;
}
static inline uint8_t calcChecksum(const Message &msg)
{
uint8_t checksum = msg.start;
for (uint16_t i = 1; i < 5 + msg.size; ++i) {
checksum ^= *(reinterpret_cast<const uint8_t *>(&msg) + i);
}
return checksum;
}
static inline bool receiveMessage(Message &msg)
{
if (!receiveByte(msg.start) || msg.start != MESSAGE_START)
return false;
if (!receiveByte(msg.number))
return false;
if (!receiveByte(*(reinterpret_cast<uint8_t *>(&msg.size) + 1)))
return false;
if (!receiveByte(*reinterpret_cast<uint8_t *>(&msg.size)) || msg.size > sizeof(msg.body))
return false;
if (!receiveByte(msg.token) || msg.token != TOKEN)
return false;
for (uint16_t i = 0; i < msg.size; ++i) {
if (!receiveByte(msg.body[i]))
return false;
}
if (!receiveByte(msg.checksum) || msg.checksum != calcChecksum(msg))
return false;
return true;
}
static inline void transmitMessage(const Message &msg)
{
serial.txByte(msg.start);
serial.txByte(msg.number);
serial.txByte(msg.size >> 8);
serial.txByte(msg.size & 0xFF);
serial.txByte(msg.token);
for (uint16_t i = 0; i < msg.size; ++i)
serial.txByte(msg.body[i]);
serial.txByte(msg.checksum);
}
static inline bool isSignOn(const Message &msg)
{
if (msg.size == 1 && msg.body[0] == CMD_SIGN_ON)
return true;
return false;
}
static inline bool isGetParameter(const Message &msg)
{
if (msg.size == 2 && msg.body[0] == CMD_GET_PARAMETER)
return true;
return false;
}
static inline bool isSetParameter(const Message &msg)
{
if (msg.size == 3 && msg.body[0] == CMD_SET_PARAMETER)
return true;
return false;
}
static inline bool isEnterProgmodeIsp(const Message &msg)
{
if (msg.size == 12 && msg.body[0] == CMD_ENTER_PROGMODE_ISP)
return true;
return false;
}
static inline bool isReadSignatureIsp(const Message &msg)
{
if (msg.size == 6 && msg.body[0] == CMD_READ_SIGNATURE_ISP)
return true;
return false;
}
static inline bool isReadFuseIsp(const Message &msg)
{
if (msg.size == 6 && msg.body[0] == CMD_READ_FUSE_ISP)
return true;
return false;
}
static inline bool isReadLockIsp(const Message &msg)
{
if (msg.size == 6 && msg.body[0] == CMD_READ_LOCK_ISP)
return true;
return false;
}
static inline bool isLoadAddress(const Message &msg)
{
if (msg.size == 5 && msg.body[0] == CMD_LOAD_ADDRESS)
return true;
return false;
}
static inline bool isReadFlashIsp(const Message &msg)
{
if (msg.size == 4 && msg.body[0] == CMD_READ_FLASH_ISP)
return true;
return false;
}
static inline bool isReadEepromIsp(const Message &msg)
{
if (msg.size == 4 && msg.body[0] == CMD_READ_EEPROM_ISP)
return true;
return false;
}
static inline bool isChipEraseIsp(const Message &msg)
{
if (msg.size == 7 && msg.body[0] == CMD_CHIP_ERASE_ISP)
return true;
return false;
}
static inline bool isProgramFlashIsp(const Message &msg)
{
if (msg.body[0] == CMD_PROGRAM_FLASH_ISP) {
const auto dataSize = static_cast<uint16_t>(msg.body[1]) << 8 | msg.body[2];
if (msg.size == (dataSize + 10) && dataSize == SPM_PAGESIZE)
return true;
}
return false;
}
static inline bool isProgramEepromIsp(const Message &msg)
{
if (msg.body[0] == CMD_PROGRAM_EEPROM_ISP) {
if (msg.size == (static_cast<uint16_t>(msg.body[1]) << 8 | msg.body[2]) + 10)
return true;
}
return false;
}
static inline bool isLeaveProgmodeIsp(const Message &msg)
{
if (msg.size == 3 && msg.body[0] == CMD_LEAVE_PROGMODE_ISP)
return true;
return false;
}
static inline void formatSignOnAnswer(Message &msg)
{
msg.size = 3 + 8;
msg.body[1] = STATUS_CMD_OK;
msg.body[2] = 8;
msg.body[3] = 'S';
msg.body[4] = 'T';
msg.body[5] = 'K';
msg.body[6] = '5';
msg.body[7] = '0';
msg.body[8] = '0';
msg.body[9] = '_';
msg.body[10] = '2';
msg.checksum = calcChecksum(msg);
}
static inline void formatGetParameterAnswer(Message &msg)
{
msg.size = 3;
if (msg.body[1] == PARAM_HW_VER) {
msg.body[2] = 1;
} else if (msg.body[1] == PARAM_SW_MAJOR) {
msg.body[2] = 0x02;
} else if (msg.body[1] == PARAM_SW_MINOR) {
msg.body[2] = 0x0a;
} else if (msg.body[1] == PARAM_SCK_DURATION) {
msg.body[2] = 2;
} else if (msg.body[1] == PARAM_VADJUST) {
msg.body[2] = 25;
} else if (msg.body[1] == PARAM_VTARGET) {
msg.body[2] = 49;
} else if (msg.body[1] == PARAM_OSC_PSCALE) {
msg.body[2] = 2;
} else if (msg.body[1] == PARAM_OSC_CMATCH) {
msg.body[2] = 127;
} else {
msg.size = 2;
}
if (msg.size == 2) {
msg.body[1] = STATUS_CMD_FAILED;
} else {
msg.body[1] = STATUS_CMD_OK;
}
msg.checksum = calcChecksum(msg);
}
static inline void formatSetParameterAnswer(Message &msg)
{
msg.size = 2;
msg.body[1] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatEnterProgmodeIspAnswer(Message &msg)
{
msg.size = 2;
msg.body[1] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatReadSignatureIspAnswer(Message &msg)
{
msg.size = 4;
msg.body[2] = boot_signature_byte_get(msg.body[4] * 2);
msg.body[1] = STATUS_CMD_OK;
msg.body[3] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatReadFuseIspAnswer(Message &msg)
{
constexpr auto READ_LOW_FUSE_BITS = 0x0050;
constexpr auto READ_HIGH_FUSE_BITS = 0x0858;
constexpr auto READ_EXTENDED_FUSE_BITS = 0x0850;
msg.size = 4;
if (*reinterpret_cast<uint16_t *>(msg.body + 2) == READ_EXTENDED_FUSE_BITS) {
msg.body[2] = boot_lock_fuse_bits_get(GET_EXTENDED_FUSE_BITS);
}
if (*reinterpret_cast<uint16_t *>(msg.body + 2) == READ_HIGH_FUSE_BITS) {
msg.body[2] = boot_lock_fuse_bits_get(GET_HIGH_FUSE_BITS);
}
if (*reinterpret_cast<uint16_t *>(msg.body + 2) == READ_LOW_FUSE_BITS) {
msg.body[2] = boot_lock_fuse_bits_get(GET_LOW_FUSE_BITS);
}
msg.body[1] = STATUS_CMD_OK;
msg.body[3] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatReadLockIspAnswer(Message &msg)
{
msg.size = 4;
msg.body[2] = boot_lock_fuse_bits_get(GET_LOCK_BITS);
msg.body[1] = STATUS_CMD_OK;
msg.body[3] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatLoadAddressAnswer(Message &msg)
{
msg.size = 2;
msg.body[1] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatReadFlashIspAnswer(Message &msg, uint32_t &addr)
{
const uint16_t numBytes = static_cast<uint16_t>(msg.body[1]) << 8 | msg.body[2];
msg.size = 3 + numBytes;
msg.body[1] = STATUS_CMD_OK;
for (uint16_t i = 0; i < numBytes; ++i) {
msg.body[i + 2] = pgm_read_byte(static_cast<uint16_t>(addr + i));
}
addr += numBytes;
msg.body[numBytes + 2] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
namespace {
bool isEepromReady()
{
return (EECR & (1 << EEPE)) ? false : true;
}
void waitEepromReady()
{
while (!isEepromReady())
;
}
uint8_t readEepromByte(const uint8_t *addr)
{
EEAR = reinterpret_cast<uint16_t>(addr);
EECR |= (1 << EERE);
return EEDR;
}
void writeEepromByte(uint8_t *addr, uint8_t value)
{
EECR = 0;
EEAR = reinterpret_cast<uint16_t>(addr);
EEDR = value;
EECR |= (1 << EEMPE);
EECR |= (1 << EEPE);
}
//////////////////////////////////////////////////////////////////////////
void writeFlashPage(uint32_t pageAddress, const uint8_t *data)
{
boot_page_erase(pageAddress);
boot_spm_busy_wait();
for (uint16_t i = 0; i < SPM_PAGESIZE; i += 2) {
uint16_t dataWord = *data++;
dataWord |= (*data++) << 8;
boot_page_fill(pageAddress + i, dataWord);
}
boot_page_write(pageAddress);
boot_spm_busy_wait();
boot_rww_enable();
}
} // namespace
static inline uint16_t getBootloaderSize()
{
const auto highFuse = boot_lock_fuse_bits_get(GET_HIGH_FUSE_BITS);
constexpr auto BOOTSZ0 = 1;
constexpr auto BOOTSZ1 = 2;
if (highFuse & (1 << BOOTSZ1) && highFuse & (1 << BOOTSZ0))
return 256 * 2;
else if (highFuse & (1 << BOOTSZ1))
return 512 * 2;
else if (highFuse & (1 << BOOTSZ0))
return 1024 * 2;
return 2048 * 2;
}
static inline uint32_t getFlashSize()
{
const auto bootloaderSize = getBootloaderSize();
return (FLASHEND - bootloaderSize + 1);
}
static inline void performChipErase()
{
constexpr auto getEepromEraseFuseBit = []() -> bool {
constexpr auto EESAVE = 3;
return boot_lock_fuse_bits_get(GET_HIGH_FUSE_BITS) & (1 << EESAVE);
};
constexpr auto eraseFlash = []() {
const auto flashSize = getFlashSize();
for (uint16_t i = 0; i < flashSize; i += SPM_PAGESIZE) {
boot_page_erase(i);
boot_spm_busy_wait();
}
boot_rww_enable();
};
constexpr auto eraseEeprom = [getEepromEraseFuseBit]() {
const auto eraseEeprom = getEepromEraseFuseBit();
if (eraseEeprom) {
constexpr auto EEPROM_SIZE = E2END + 1;
for (uint16_t i = 0; i < EEPROM_SIZE; ++i) {
writeEepromByte(reinterpret_cast<uint8_t *>(i), 0xFF);
waitEepromReady();
}
}
};
eraseFlash();
eraseEeprom();
}
static inline void formatChipEraseIspAnswer(Message &msg)
{
msg.size = 2;
msg.body[1] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatReadEepromIspAnswer(Message &msg, uint32_t &addr)
{
const uint16_t numBytes = static_cast<uint16_t>(msg.body[1]) << 8 | msg.body[2];
msg.size = 3 + numBytes;
msg.body[1] = STATUS_CMD_OK;
for (uint16_t i = 0; i < numBytes; ++i) {
msg.body[i + 2] = readEepromByte(reinterpret_cast<const uint8_t *>(addr + i));
}
addr += numBytes;
msg.body[numBytes + 2] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatProgramFlashIspAnswer(Message &msg, uint32_t &addr)
{
if (addr < getFlashSize())
writeFlashPage(addr, msg.body + 10);
const uint16_t numBytes = static_cast<uint16_t>(msg.body[1]) << 8 | msg.body[2];
addr += numBytes;
msg.size = 2;
msg.body[1] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatProgramEepromIspAnswer(Message &msg, uint32_t &addr)
{
const uint16_t numBytes = static_cast<uint16_t>(msg.body[1]) << 8 | msg.body[2];
for (uint16_t i = 0; i < numBytes; ++i) {
writeEepromByte(reinterpret_cast<uint8_t *>(addr + i), msg.body[10 + i]);
waitEepromReady();
}
addr += numBytes;
msg.size = 2;
msg.body[1] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatLeaveProgmodeIspAnswer(Message &msg)
{
msg.size = 2;
msg.body[1] = STATUS_CMD_OK;
msg.checksum = calcChecksum(msg);
}
static inline void formatErrorAnswer(Message &msg)
{
msg.start = MESSAGE_START;
msg.size = 1;
msg.token = TOKEN;
msg.body[0] = STATUS_CMD_UNKNOWN;
msg.checksum = calcChecksum(msg);
}
enum class ChipEraseState {
NONE = 0b00,
REQUEST = 0b01,
RESPONSE = 0b10,
PERFORM = 0b11,
};
constexpr ChipEraseState operator|(const ChipEraseState &self, const ChipEraseState &other)
{
return static_cast<ChipEraseState>(static_cast<uint8_t>(self) | static_cast<uint8_t>(other));
}
constexpr ChipEraseState &operator|=(ChipEraseState &self, const ChipEraseState &other)
{
self = self | other;
return self;
}
static inline void handleMessage(Message &msg, uint32_t &addr, ChipEraseState &chipEraseFlag)
{
if (isSignOn(msg))
formatSignOnAnswer(msg);
else if (isGetParameter(msg))
formatGetParameterAnswer(msg);
else if (isSetParameter(msg))
formatSetParameterAnswer(msg);
else if (isEnterProgmodeIsp(msg))
formatEnterProgmodeIspAnswer(msg);
else if (isReadSignatureIsp(msg))
formatReadSignatureIspAnswer(msg);
else if (isReadFuseIsp(msg))
formatReadFuseIspAnswer(msg);
else if (isReadLockIsp(msg))
formatReadLockIspAnswer(msg);
else if (isLoadAddress(msg)) {
addr = msg.body[1];
addr = (addr << 8) | msg.body[2];
addr = (addr << 8) | msg.body[3];
addr = (addr << 8) | msg.body[4];
formatLoadAddressAnswer(msg);
} else if (isReadFlashIsp(msg))
formatReadFlashIspAnswer(msg, addr);
else if (isReadEepromIsp(msg))
formatReadEepromIspAnswer(msg, addr);
else if (isChipEraseIsp(msg)) {
chipEraseFlag = ChipEraseState::REQUEST;
formatChipEraseIspAnswer(msg);
} else if (isProgramFlashIsp(msg))
formatProgramFlashIspAnswer(msg, addr);
else if (isProgramEepromIsp(msg))
formatProgramEepromIspAnswer(msg, addr);
else if (isLeaveProgmodeIsp(msg)) {
chipEraseFlag |= ChipEraseState::RESPONSE;
formatLeaveProgmodeIspAnswer(msg);
} else
formatErrorAnswer(msg);
transmitMessage(msg);
if (chipEraseFlag == ChipEraseState::PERFORM) {
performChipErase();
chipEraseFlag = ChipEraseState::NONE;
}
}
int main()
{
serial.init();
Message msg;
uint32_t addr = 0x0000;
ChipEraseState chipEraseFlag = ChipEraseState::NONE;
while (true) {
if (receiveMessage(msg)) {
handleMessage(msg, addr, chipEraseFlag);
}
}
return 0;
}
void startup() __attribute__((naked, section(".vectors")));
void startup()
{
asm volatile("clr __zero_reg__");
// SP = RAMEND;
SREG = 0;
asm volatile("jmp main");
}

286
stk500v2/stk500v2.cppproj
View File

@@ -1,286 +0,0 @@
<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="14.0">
<PropertyGroup>
<SchemaVersion>2.0</SchemaVersion>
<ProjectVersion>7.0</ProjectVersion>
<ToolchainName>com.Atmel.AVRGCC8.CPP</ToolchainName>
<ProjectGuid>{19798cce-5d96-40e9-b769-d209715dce0c}</ProjectGuid>
<avrdevice>ATmega328P</avrdevice>
<avrdeviceseries>none</avrdeviceseries>
<OutputType>Executable</OutputType>
<Language>CPP</Language>
<OutputFileName>$(MSBuildProjectName)</OutputFileName>
<OutputFileExtension>.elf</OutputFileExtension>
<OutputDirectory>$(MSBuildProjectDirectory)\$(Configuration)</OutputDirectory>
<AssemblyName>stk500v2</AssemblyName>
<Name>stk500v2</Name>
<RootNamespace>stk500v2</RootNamespace>
<ToolchainFlavour>avr-g++-9.1.0</ToolchainFlavour>
<KeepTimersRunning>true</KeepTimersRunning>
<OverrideVtor>false</OverrideVtor>
<CacheFlash>true</CacheFlash>
<ProgFlashFromRam>true</ProgFlashFromRam>
<RamSnippetAddress>0x20000000</RamSnippetAddress>
<UncachedRange />
<preserveEEPROM>true</preserveEEPROM>
<OverrideVtorValue>exception_table</OverrideVtorValue>
<BootSegment>2</BootSegment>
<ResetRule>0</ResetRule>
<eraseonlaunchrule>0</eraseonlaunchrule>
<EraseKey />
<avrtool>com.atmel.avrdbg.tool.atmelice</avrtool>
<avrtoolserialnumber>J41800099437</avrtoolserialnumber>
<avrdeviceexpectedsignature>0x1E950F</avrdeviceexpectedsignature>
<com_atmel_avrdbg_tool_stk500>
<ToolOptions>
<InterfaceProperties>
<IspClock>125000</IspClock>
</InterfaceProperties>
<InterfaceName>ISP</InterfaceName>
</ToolOptions>
<ToolType>com.atmel.avrdbg.tool.stk500</ToolType>
<ToolNumber>
</ToolNumber>
<ToolName>STK500</ToolName>
</com_atmel_avrdbg_tool_stk500>
<avrtoolinterface>ISP</avrtoolinterface>
<avrtoolinterfaceclock>125000</avrtoolinterfaceclock>
<AsfFrameworkConfig>
<framework-data xmlns="">
<options />
<configurations />
<files />
<documentation help="" />
<offline-documentation help="" />
<dependencies>
<content-extension eid="atmel.asf" uuidref="Atmel.ASF" version="3.47.0" />
</dependencies>
</framework-data>
</AsfFrameworkConfig>
<com_atmel_avrdbg_tool_atmelice>
<ToolOptions>
<InterfaceProperties>
<IspClock>125000</IspClock>
</InterfaceProperties>
<InterfaceName>ISP</InterfaceName>
</ToolOptions>
<ToolType>com.atmel.avrdbg.tool.atmelice</ToolType>
<ToolNumber>J41800099437</ToolNumber>
<ToolName>Atmel-ICE</ToolName>
</com_atmel_avrdbg_tool_atmelice>
<custom>
<ToolOptions>
<InterfaceProperties>
<IspClock>125000</IspClock>
</InterfaceProperties>
<InterfaceName>
</InterfaceName>
</ToolOptions>
<ToolType>custom</ToolType>
<ToolNumber>
</ToolNumber>
<ToolName>Custom Programming Tool</ToolName>
</custom>
<com_atmel_avrdbg_tool_simulator>
<ToolOptions xmlns="">
<InterfaceProperties>
</InterfaceProperties>
<InterfaceName>
</InterfaceName>
</ToolOptions>
<ToolType xmlns="">com.atmel.avrdbg.tool.simulator</ToolType>
<ToolNumber xmlns="">
</ToolNumber>
<ToolName xmlns="">Simulator</ToolName>
</com_atmel_avrdbg_tool_simulator>
<AAFDebugger>
<AAFDebugFiles>
<DebugFile>
<path>\Debug\stk500v2.lss</path>
<AAFSetting>
<Label>Lss Files</Label>
<Extention>.lss</Extention>
<Regex>^\s*(?&lt;address&gt;[a-f0-9]*):\s*.*$</Regex>
<DebugEnabled>true</DebugEnabled>
<RegexGroups>address</RegexGroups>
<DebuggerExpression>$pc</DebuggerExpression>
</AAFSetting>
</DebugFile>
</AAFDebugFiles>
</AAFDebugger>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
<ToolchainSettings>
<AvrGccCpp>
<avrgcc.common.Device>-mmcu=atmega328p</avrgcc.common.Device>
<avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
<avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
<avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
<avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
<avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
<avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>
<avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>
<avrgcc.compiler.symbols.DefSymbols>
<ListValues>
<Value>NDEBUG</Value>
</ListValues>
</avrgcc.compiler.symbols.DefSymbols>
<avrgcc.compiler.directories.IncludePaths>
<ListValues>
<Value>%24(PackRepoDir)\Atmel\ATmega_DFP\1.4.346\include</Value>
</ListValues>
</avrgcc.compiler.directories.IncludePaths>
<avrgcc.compiler.optimization.level>Optimize for size (-Os)</avrgcc.compiler.optimization.level>
<avrgcc.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcc.compiler.optimization.AllocateBytesNeededForEnum>
<avrgcc.compiler.warnings.AllWarnings>True</avrgcc.compiler.warnings.AllWarnings>
<avrgcc.compiler.warnings.ExtraWarnings>True</avrgcc.compiler.warnings.ExtraWarnings>
<avrgcc.compiler.warnings.Pedantic>True</avrgcc.compiler.warnings.Pedantic>
<avrgcc.compiler.miscellaneous.OtherFlags>-fno-threadsafe-statics -std=c11</avrgcc.compiler.miscellaneous.OtherFlags>
<avrgcccpp.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcccpp.compiler.general.ChangeDefaultCharTypeUnsigned>
<avrgcccpp.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcccpp.compiler.general.ChangeDefaultBitFieldUnsigned>
<avrgcccpp.compiler.symbols.DefSymbols>
<ListValues>
<Value>NDEBUG</Value>
</ListValues>
</avrgcccpp.compiler.symbols.DefSymbols>
<avrgcccpp.compiler.directories.IncludePaths>
<ListValues>
<Value>%24(PackRepoDir)\Atmel\ATmega_DFP\1.4.346\include</Value>
</ListValues>
</avrgcccpp.compiler.directories.IncludePaths>
<avrgcccpp.compiler.optimization.level>Optimize for size (-Os)</avrgcccpp.compiler.optimization.level>
<avrgcccpp.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcccpp.compiler.optimization.AllocateBytesNeededForEnum>
<avrgcccpp.compiler.warnings.AllWarnings>True</avrgcccpp.compiler.warnings.AllWarnings>
<avrgcccpp.compiler.warnings.Pedantic>True</avrgcccpp.compiler.warnings.Pedantic>
<avrgcccpp.compiler.miscellaneous.OtherFlags>-fno-threadsafe-statics -Wextra -std=c++17</avrgcccpp.compiler.miscellaneous.OtherFlags>
<avrgcccpp.linker.general.NoStartupOrDefaultLibs>True</avrgcccpp.linker.general.NoStartupOrDefaultLibs>
<avrgcccpp.linker.libraries.Libraries>
<ListValues>
<Value>libm</Value>
</ListValues>
</avrgcccpp.linker.libraries.Libraries>
<avrgcccpp.linker.memorysettings.Flash>
<ListValues>
<Value>.text=0x3C00</Value>
</ListValues>
</avrgcccpp.linker.memorysettings.Flash>
<avrgcccpp.assembler.general.IncludePaths>
<ListValues>
<Value>%24(PackRepoDir)\Atmel\ATmega_DFP\1.4.346\include</Value>
</ListValues>
</avrgcccpp.assembler.general.IncludePaths>
</AvrGccCpp>
</ToolchainSettings>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
<ToolchainSettings>
<AvrGccCpp>
<avrgcc.common.Device>-mmcu=atmega328p</avrgcc.common.Device>
<avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
<avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
<avrgcc.common.outputfiles.eep>True</avrgcc.common.outputfiles.eep>
<avrgcc.common.outputfiles.srec>True</avrgcc.common.outputfiles.srec>
<avrgcc.common.outputfiles.usersignatures>False</avrgcc.common.outputfiles.usersignatures>
<avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcc.compiler.general.ChangeDefaultCharTypeUnsigned>
<avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcc.compiler.general.ChangeDefaultBitFieldUnsigned>
<avrgcc.compiler.symbols.DefSymbols>
<ListValues>
<Value>DEBUG</Value>
</ListValues>
</avrgcc.compiler.symbols.DefSymbols>
<avrgcc.compiler.directories.IncludePaths>
<ListValues>
<Value>%24(PackRepoDir)\Atmel\ATmega_DFP\1.4.346\include</Value>
</ListValues>
</avrgcc.compiler.directories.IncludePaths>
<avrgcc.compiler.optimization.level>Optimize (-O1)</avrgcc.compiler.optimization.level>
<avrgcc.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcc.compiler.optimization.AllocateBytesNeededForEnum>
<avrgcc.compiler.optimization.DebugLevel>Maximum (-g3)</avrgcc.compiler.optimization.DebugLevel>
<avrgcc.compiler.warnings.AllWarnings>True</avrgcc.compiler.warnings.AllWarnings>
<avrgcc.compiler.warnings.ExtraWarnings>True</avrgcc.compiler.warnings.ExtraWarnings>
<avrgcc.compiler.warnings.Pedantic>True</avrgcc.compiler.warnings.Pedantic>
<avrgcc.compiler.miscellaneous.OtherFlags>-fno-threadsafe-statics -std=c11</avrgcc.compiler.miscellaneous.OtherFlags>
<avrgcccpp.compiler.general.ChangeDefaultCharTypeUnsigned>True</avrgcccpp.compiler.general.ChangeDefaultCharTypeUnsigned>
<avrgcccpp.compiler.general.ChangeDefaultBitFieldUnsigned>True</avrgcccpp.compiler.general.ChangeDefaultBitFieldUnsigned>
<avrgcccpp.compiler.symbols.DefSymbols>
<ListValues>
<Value>DEBUG</Value>
</ListValues>
</avrgcccpp.compiler.symbols.DefSymbols>
<avrgcccpp.compiler.directories.IncludePaths>
<ListValues>
<Value>%24(PackRepoDir)\Atmel\ATmega_DFP\1.4.346\include</Value>
</ListValues>
</avrgcccpp.compiler.directories.IncludePaths>
<avrgcccpp.compiler.optimization.level>Optimize debugging experience (-Og)</avrgcccpp.compiler.optimization.level>
<avrgcccpp.compiler.optimization.AllocateBytesNeededForEnum>True</avrgcccpp.compiler.optimization.AllocateBytesNeededForEnum>
<avrgcccpp.compiler.optimization.DebugLevel>Maximum (-g3)</avrgcccpp.compiler.optimization.DebugLevel>
<avrgcccpp.compiler.warnings.AllWarnings>True</avrgcccpp.compiler.warnings.AllWarnings>
<avrgcccpp.compiler.warnings.Pedantic>True</avrgcccpp.compiler.warnings.Pedantic>
<avrgcccpp.compiler.miscellaneous.OtherFlags>-fno-threadsafe-statics -Wextra -std=c++17</avrgcccpp.compiler.miscellaneous.OtherFlags>
<avrgcccpp.linker.general.NoStartupOrDefaultLibs>True</avrgcccpp.linker.general.NoStartupOrDefaultLibs>
<avrgcccpp.linker.libraries.Libraries>
<ListValues>
<Value>libm</Value>
</ListValues>
</avrgcccpp.linker.libraries.Libraries>
<avrgcccpp.linker.memorysettings.Flash>
<ListValues>
<Value>.text=0x3800</Value>
</ListValues>
</avrgcccpp.linker.memorysettings.Flash>
<avrgcccpp.assembler.general.IncludePaths>
<ListValues>
<Value>%24(PackRepoDir)\Atmel\ATmega_DFP\1.4.346\include</Value>
</ListValues>
</avrgcccpp.assembler.general.IncludePaths>
<avrgcccpp.assembler.debugging.DebugLevel>Default (-Wa,-g)</avrgcccpp.assembler.debugging.DebugLevel>
</AvrGccCpp>
</ToolchainSettings>
</PropertyGroup>
<ItemGroup>
<Compile Include="clock.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="command.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="flash\flash.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="io\io.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="main.cpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="type\type.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="uart\config.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="uart\hardware.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="uart\hardware0.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="uart\hardware1.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="uart\software.hpp">
<SubType>compile</SubType>
</Compile>
<Compile Include="uart\uart.hpp">
<SubType>compile</SubType>
</Compile>
</ItemGroup>
<ItemGroup>
<Folder Include="flash" />
<Folder Include="io" />
<Folder Include="uart" />
<Folder Include="type" />
</ItemGroup>
<Import Project="$(AVRSTUDIO_EXE_PATH)\\Vs\\Compiler.targets" />
</Project>

1
stk500v2/type

Submodule stk500v2/type deleted from ce31ef017f

1
stk500v2/uart

Submodule stk500v2/uart deleted from ae03c8d43e

14
test/check_size.cmake Normal file
View File

@@ -0,0 +1,14 @@
execute_process(COMMAND ${SIZE_TOOL} ${ELF} OUTPUT_VARIABLE _out RESULT_VARIABLE _res)
if(NOT _res EQUAL 0)
message(FATAL_ERROR "avr-size failed")
endif()
# avr-size line 2 is "<text> <data> <bss> <dec> <hex> <file>".
string(REGEX MATCH "\n[ \t]*([0-9]+)" _m "${_out}")
if(NOT _m)
message(FATAL_ERROR "could not read a .text size out of ${SIZE_TOOL}'s output for ${ELF}:\n${_out}")
endif()
set(_text ${CMAKE_MATCH_1})
if(_text GREATER LIMIT)
message(FATAL_ERROR ".text is ${_text} bytes, over the ${LIMIT}-byte boot section")
endif()
message(STATUS ".text ${_text} <= ${LIMIT} (boot section budget)")

128
test/device.cpp Normal file
View File

@@ -0,0 +1,128 @@
// simavr "device" for the TSB bootloader: load the boot-linked ELF into the
// ATmega328P boot section, enter it (BOOTRST is not modelled, so we set PC to
// the boot base, exactly as simavr's own board_simduino does), and expose
// UART0 as a pty. A host client (Python pyserial, or the real tsbloader) then
// speaks the TSB protocol over that pty and actually flashes the device.
//
// SPM genuinely writes avr->flash on the mega cores, so on exit (or SIGTERM)
// we dump the flash image to a file for a ground-truth cross-check against
// what the client read back through the bootloader.
#include <array>
#include <csignal>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <print>
#include <unistd.h>
// The parts headers (uart_pty.h) carry no C++ linkage guards of their own,
// unlike simavr's core headers - the block covers both harmlessly.
extern "C" {
#include "avr_uart.h"
#include "sim_avr.h"
#include "sim_elf.h"
#include "uart_pty.h"
}
namespace {
avr_t *avr;
uart_pty_t uart_pty;
const char *dump_path;
[[noreturn]] void finish(int)
{
if (dump_path) {
std::FILE *f = std::fopen(dump_path, "wb");
if (f) {
std::fwrite(avr->flash, 1, avr->flashend + 1, f);
std::fclose(f);
}
}
uart_pty_stop(&uart_pty);
_exit(0);
}
} // namespace
int main(int argc, char *argv[])
{
if (argc < 3) {
std::println(stderr, "usage: {} <tsb.elf> <boot_base_hex> [flash_dump.bin]", argv[0]);
return 2;
}
auto boot_base = static_cast<std::uint32_t>(std::strtoul(argv[2], nullptr, 0));
dump_path = argc >= 4 ? argv[3] : nullptr;
avr = avr_make_mcu_by_name("atmega328p");
if (!avr) {
std::println(stderr, "device: no ATmega328P core");
return 1;
}
avr_init(avr);
avr->frequency = 16000000;
// Real flash powers up erased (0xff); the app region must look erased
// before the bootloader programs it.
std::memset(avr->flash, 0xff, avr->flashend + 1);
// simavr's ELF loader flattens the flash base to 0 (it expects an app at
// 0x0), but it hands back the boot code in fw.flash; place it at the boot
// section base ourselves and enter there (BOOTRST is not modelled).
elf_firmware_t fw{};
if (elf_read_firmware(argv[1], &fw) != 0) {
std::println(stderr, "device: cannot read {}", argv[1]);
return 1;
}
// An image that runs past flash end cannot execute on hardware, and a
// naive copy of it would smash the heap beyond avr->flash - after which
// the simulation misbehaves in ways that point everywhere but here.
// Refuse it loudly instead.
if (boot_base + fw.flashsize > avr->flashend + 1) {
std::println(stderr, "device: {} B at {:#x} runs past flash end {:#x} - image does not fit its slot",
fw.flashsize, boot_base, avr->flashend);
return 1;
}
std::memcpy(avr->flash + boot_base, fw.flash, fw.flashsize);
avr->pc = boot_base;
avr->codeend = avr->flashend;
// Optional: seed the config page (one page below the boot section) with a
// hex byte string, so the password gate and emergency erase can be tested.
// Layout: [appjump lo][appjump hi][timeout][password...][0xff].
const char *cfg = std::getenv("TSB_CONFIG");
if (cfg) {
std::uint32_t app_end = boot_base - 128; // config page sits directly below the boot code
for (int i = 0; cfg[i] && cfg[i + 1]; i += 2) {
const std::array pair{cfg[i], cfg[i + 1], '\0'};
avr->flash[app_end + i / 2] = static_cast<std::uint8_t>(std::strtoul(pair.data(), nullptr, 16));
}
}
// POLL_SLEEP makes simavr usleep(1) on every status-register read while the
// UART is idle - a host-CPU-saving hack that models no hardware and paces a
// tight-polling loader (one that releases TX between bytes, as one-wire does)
// in real time, distorting protocol timing. Clear it so the loader runs at
// true cycle speed.
std::uint32_t uflags = 0;
avr_ioctl(avr, AVR_IOCTL_UART_GET_FLAGS('0'), &uflags);
uflags &= ~AVR_UART_FLAG_POLL_SLEEP;
avr_ioctl(avr, AVR_IOCTL_UART_SET_FLAGS('0'), &uflags);
uart_pty_init(avr, &uart_pty);
uart_pty_connect(&uart_pty, '0');
std::println("TSB_PTY {}", uart_pty.pty.slavename);
std::fflush(stdout);
std::signal(SIGTERM, finish);
std::signal(SIGINT, finish);
for (;;) {
int state = avr_run(avr);
if (state == cpu_Done || state == cpu_Crashed) {
break;
}
}
finish(0);
}

276
test/tsbtest.py Normal file
View File

@@ -0,0 +1,276 @@
#!/usr/bin/env python3
"""End-to-end TSB protocol test: spawn the simavr device, speak the TinySafeBoot
wire protocol over its pty (as the real host tools do), and actually flash it.
Usage: tsbtest.py <device_binary> <tsb.elf> <boot_base_hex>
Exits 0 if every scenario passes.
"""
import os
import subprocess
import sys
import time
import serial
CONFIRM = 0x21 # '!'
REQUEST = 0x3F # '?'
KNOCK = 0x40 # '@'
PAGE = 128 # ATmega328P: 64 words
class Device:
"""The simavr runner, exposing UART0 as a pty. `config` seeds the config
page (via the device's TSB_CONFIG hook) so the password gate and emergency
erase are exercisable."""
def __init__(self, binary, elf, boot_base, dump="/tmp/tsb_dump.bin", config=None):
env = dict(os.environ)
if config is not None:
env["TSB_CONFIG"] = config
self.proc = subprocess.Popen(
[binary, elf, boot_base, dump],
stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True, env=env)
self.dump = dump
self.pty = None
deadline = time.time() + 5
while time.time() < deadline:
line = self.proc.stdout.readline()
if not line:
break
if line.startswith("TSB_PTY"):
self.pty = line.split()[1]
break
if not self.pty:
self.stop()
raise RuntimeError("device did not report a pty")
def stop(self):
self.proc.terminate()
try:
self.proc.wait(timeout=3)
except subprocess.TimeoutExpired:
self.proc.kill()
class Host:
"""A faithful TSB host, per the wire protocol."""
def __init__(self, pty):
self.s = serial.Serial(pty, 115200, timeout=1.5)
self.info = None
def _read(self, n):
data = self.s.read(n)
if len(data) != n:
raise AssertionError(f"expected {n} bytes, got {len(data)}: {data.hex()}")
return data
def activate(self):
self.s.reset_input_buffer()
self.s.write(b"@@@")
reply = self._read(17)
if reply[16] != CONFIRM:
raise AssertionError(f"activation reply not '!'-terminated: {reply.hex()}")
self.info = reply[:16]
return self.info
# Parsed info-block fields (host math from the spec).
@property
def pagesize(self):
return self.info[9] * 2
@property
def appflash(self):
return (self.info[10] | (self.info[11] << 8)) * 2
@property
def eeprom_size(self):
return (self.info[12] | (self.info[13] << 8)) + 1
def _expect(self, byte, what):
r = self._read(1)
if r[0] != byte:
raise AssertionError(f"{what}: expected {byte:#x}, got {r.hex()}")
# Host-paced page read ('f'/'e'): send '!', take a page, repeat; stop with
# anything else, then the Mainloop '!'.
def _read_pages(self, cmd, npages):
self.s.write(cmd.encode())
data = b""
for _ in range(npages):
self.s.write(bytes([CONFIRM]))
data += self._read(PAGE)
self.s.write(bytes([REQUEST])) # stop
self._expect(CONFIRM, f"{cmd} end")
return data
# Device-paced page write ('F'/'E'): device offers '?', host sends '!'+page,
# or anything else to stop.
def _write_pages(self, cmd, data):
if len(data) % PAGE:
data += b"\xff" * (PAGE - len(data) % PAGE)
self.s.write(cmd.encode())
for off in range(0, len(data), PAGE):
self._expect(REQUEST, f"{cmd} '?'")
self.s.write(bytes([CONFIRM]) + data[off:off + PAGE])
self._expect(REQUEST, f"{cmd} trailing '?'")
self.s.write(bytes([REQUEST])) # stop
self._expect(CONFIRM, f"{cmd} end")
def write_flash(self, data):
self._write_pages("F", data)
def read_flash(self, npages):
return self._read_pages("f", npages)
def write_eeprom(self, data):
self._write_pages("E", data)
def read_eeprom(self, npages):
return self._read_pages("e", npages)
def read_config(self):
self.s.write(b"c")
page = self._read(PAGE)
self._expect(CONFIRM, "c end")
return page
def write_config(self, data):
assert len(data) == PAGE
self.s.write(b"C")
self._expect(REQUEST, "C '?'")
self.s.write(bytes([CONFIRM]) + data)
echo = self._read(PAGE) # device echoes what it programmed
self._expect(CONFIRM, "C end")
return echo
# Activation when the config page carries a password: 3x'@' then the
# password bytes, then the info block + mainloop '!'.
def activate_password(self, password):
self.s.reset_input_buffer()
self.s.write(bytes([KNOCK, KNOCK, KNOCK]) + password)
reply = self._read(17)
if reply[16] != CONFIRM:
raise AssertionError(f"password activation not '!'-terminated: {reply.hex()}")
self.info = reply[:16]
return self.info
# A 0 byte where a password byte is expected requests emergency erase; the
# device asks for two confirmations, then wipes and returns to the mainloop.
def emergency_erase(self):
self.s.reset_input_buffer()
self.s.write(bytes([KNOCK, KNOCK, KNOCK, 0x00]))
self._expect(REQUEST, "emergency confirm 1")
self.s.write(bytes([CONFIRM]))
self._expect(REQUEST, "emergency confirm 2")
self.s.write(bytes([CONFIRM]))
self._expect(CONFIRM, "emergency mainloop ready")
# A wrong password byte hangs the loader, still draining the line. Two
# things must not happen: it must not activate, and it must not fall
# through to the emergency erase - a byte the gate has already refused
# reaching the erase would let a guess wipe the part.
def refuse_password(self, byte):
self.s.reset_input_buffer()
self.s.write(bytes([KNOCK, KNOCK, KNOCK, byte]))
return self.s.read(1)
def say(self, byte):
self.s.write(bytes([byte]))
return self.s.read(1)
def check(cond, msg):
if not cond:
raise AssertionError(msg)
print(f" ok: {msg}")
# A config page carrying a password "PW": appjump 0, timeout 0x40, password
# 0x50 0x57 terminated by 0xff.
PW_CONFIG = "0000405057ff"
PW_BYTES = bytes([0x50, 0x57])
def scenario_roundtrip(host):
"""Activation + info block + flash/EEPROM/config read-write round-trips, on
a device with a blank (erased) config page - the usual no-password case."""
info = host.activate()
check(info[0:3] == b"TSB", f"magic 'TSB' (got {info[0:3]!r})")
check(info[6:9] == bytes([0x1E, 0x95, 0x0F]), f"signature 1E 95 0F (got {info[6:9].hex()})")
check(info[14] == info[15], f"device-type bytes 14==15 (got {info[14]:#x},{info[15]:#x})")
check(host.pagesize == PAGE, f"page size {PAGE} (got {host.pagesize})")
check(host.eeprom_size == 1024, f"eeprom size 1024 (got {host.eeprom_size})")
print(f" info: {info.hex()} appflash={host.appflash} eeprom={host.eeprom_size}")
app = bytes(range(256)) # two pages of known data
host.write_flash(app)
check(host.read_flash(2) == app, "flash round-trip 2 pages")
edata = bytes((i * 7) & 0xFF for i in range(PAGE))
host.write_eeprom(edata)
check(host.read_eeprom(1) == edata, "eeprom round-trip 1 page")
cfg = bytes([0x00, 0x00, 0x40]) + b"\xff" * (PAGE - 3) # timeout 0x40, no password
check(host.write_config(cfg) == cfg, "config write echoes the programmed page")
check(host.read_config() == cfg, "config read-back matches")
def scenario_password(host):
"""A device whose config page carries a password activates only when the
host sends it after the knock."""
info = host.activate_password(PW_BYTES)
check(info[0:3] == b"TSB", f"password activation returns the info block (got {info[0:3]!r})")
def scenario_emergency(host):
"""Emergency erase (password 0-byte + two confirms) wipes flash, EEPROM and
the config page; the device stays alive in its boot section."""
host.emergency_erase()
check(host.read_config() == b"\xff" * PAGE, "config page wiped")
check(host.read_flash(1) == b"\xff" * PAGE, "application flash wiped")
check(host.read_eeprom(1) == b"\xff" * PAGE, "EEPROM wiped")
def scenario_wrong_password(host):
"""A wrong password byte neither activates the loader nor opens the
emergency erase behind it - the oracle carries a dedicated fix for the
second, and nothing here exercised either half."""
check(host.refuse_password(PW_BYTES[0] ^ 1) == b"", "a wrong password byte draws no reply")
check(host.say(0x00) == b"", "a 0 byte after it does not request the erase")
check(host.say(CONFIRM) == b"", "and neither does a confirm")
def main():
binary, elf, boot_base = sys.argv[1], sys.argv[2], sys.argv[3]
failures = []
# Each group runs on its own freshly-reset device (simavr reloads the ELF,
# so nothing persists between them); the password groups seed a config page.
groups = [
("round-trip", None, scenario_roundtrip),
("password activation", PW_CONFIG, scenario_password),
("emergency erase", PW_CONFIG, scenario_emergency),
("wrong password", PW_CONFIG, scenario_wrong_password),
]
for name, config, fn in groups:
print(f"--- {name} ---")
dev = Device(binary, elf, boot_base, config=config)
try:
fn(Host(dev.pty))
except AssertionError as e:
failures.append(f"{name}: {e}")
print(f" FAIL: {e}")
finally:
dev.stop()
if failures:
print(f"FAILED ({len(failures)})")
return 1
print("ALL PASS")
return 0
if __name__ == "__main__":
sys.exit(main())

60
tools/check.sh Executable file
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@@ -0,0 +1,60 @@
#!/bin/bash
# The port's gate: the generated workflow - build, size tests, and the
# simulator-driven protocol suite. --full adds the reflect build, which
# compiles the same TUs through libavr's other producer. libavr resolves from
# the `libavr/` submodule; LIBAVR_ROOT overrides it for a working tree.
set -e
cd "$(dirname "$0")/.."
full=0
[[ "$1" == "--full" ]] && { full=1; shift; }
# The chip lists come from the presets rather than being spelled a second time
# here: a chip added to make_presets.py and missed in a copy of its list would
# be a gate that silently never builds it, which is the one failure mode a gate
# cannot report. tools/make_presets.py is the single source, CMakePresets.json
# is its output, and this reads that.
readarray -t WORKFLOWS < <(python3 -c '
import json, sys
presets = json.load(open("CMakePresets.json"))["workflowPresets"]
print("\n".join(p["name"] for p in presets))')
if ((${#WORKFLOWS[@]} == 0)); then
echo "no workflow presets in CMakePresets.json - run tools/make_presets.py" >&2
exit 1
fi
CHIPS=()
REFLECT_SPOT=()
for workflow in "${WORKFLOWS[@]}"; do
case $workflow in
*-generated) CHIPS+=("${workflow%-generated}") ;;
*-reflect) REFLECT_SPOT+=("${workflow%-reflect}") ;;
esac
done
# Every preset runs even after one goes red, and the gate fails at the end
# naming all of them: stopping at the first failure turns a red - a stale size
# canary above all - into an alibi for every chip behind it, and a loader can
# ship on a chip this gate has not compiled since.
red=()
run_preset() {
echo "==== $1 ===="
cmake --workflow --preset "$1" "${@:2}" || red+=("$1")
}
for chip in "${CHIPS[@]}"; do
run_preset "$chip-generated" "$@"
done
if ((full)); then
for chip in "${REFLECT_SPOT[@]}"; do
run_preset "$chip-reflect" "$@"
done
fi
if ((${#red[@]})); then
printf '==== red presets ====\n' >&2
printf ' %s\n' "${red[@]}" >&2
exit 1
fi
echo "check: every chip green"

90
tools/make_presets.py Executable file
View File

@@ -0,0 +1,90 @@
#!/usr/bin/env python3
"""Regenerate CMakePresets.json - one uniform pipeline per chip.
The tiers reimplement the ATmega328P-only reference protocol, so that is the
whole chip list. It stays a generated file rather than a hand-written one
because the shape - configure, build, test, workflow, and a reflect pair
without tests - is the shape a second chip would need too.
Run from the repo root: tools/make_presets.py - or with --check, which
verifies the committed file matches this generator and edits nothing (the
ctest entry `presets.generated` runs that, so drift reds the gate).
"""
import json
import os
import sys
CHIPS = [
"atmega328p",
]
# The reflect pair: the same chip, built in libavr's other mode.
REFLECT_SPOT = [
"atmega328p",
]
def main():
configure = [{
"name": "base",
"hidden": True,
"generator": "Ninja",
"binaryDir": "${sourceDir}/build/${presetName}",
"toolchainFile": "${sourceDir}/libavr/cmake/avr-toolchain.cmake",
"cacheVariables": {
"CMAKE_BUILD_TYPE": "Release",
"CMAKE_EXPORT_COMPILE_COMMANDS": "ON",
"CMAKE_COLOR_DIAGNOSTICS": "ON",
},
}]
build, test, workflows = [], [], []
def add(chip, mode):
name = f"{chip}-{mode}"
configure.append({
"name": name,
"inherits": "base",
"cacheVariables": {
"LIBAVR_MCU": chip,
"LIBAVR_REFLECT": "ON" if mode == "reflect" else "OFF",
},
})
build.append({"name": name, "configurePreset": name})
steps = [{"type": "configure", "name": name}, {"type": "build", "name": name}]
if mode == "generated":
test.append({"name": name, "configurePreset": name, "output": {"outputOnFailure": True}})
steps.append({"type": "test", "name": name})
workflows.append({"name": name, "steps": steps})
for chip in CHIPS:
add(chip, "generated")
for chip in REFLECT_SPOT:
add(chip, "reflect")
# CMake rejects unknown fields in the presets root, $comment included, so
# the file cannot carry a generated-file marker; the --check ctest is the
# whole of rule 10's guard here.
presets = {
"version": 8,
"configurePresets": configure,
"buildPresets": build,
"testPresets": test,
"workflowPresets": workflows,
}
rendered = json.dumps(presets, indent=1) + "\n"
path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "CMakePresets.json")
if "--check" in sys.argv[1:]:
current = open(path).read() if os.path.exists(path) else ""
if current != rendered:
print("CMakePresets.json does not match its generator - run tools/make_presets.py")
return 1
return 0
with open(path, "w") as f:
f.write(rendered)
print(f"{len(CHIPS)} chips, {len(REFLECT_SPOT)} reflect: {os.path.normpath(path)}")
return 0
if __name__ == "__main__":
sys.exit(main())

4
tsb/clock.hpp
View File

@@ -1,4 +0,0 @@
#pragma once
#define F_CPU 18'432'000
#include <util/delay.h>

1
tsb/flash

Submodule tsb/flash deleted from 6edb2e5a21

1
tsb/io

Submodule tsb/io deleted from 80de36ee7e

102
tsb/main.cpp
View File

@@ -1,102 +0,0 @@
#include "clock.hpp"
#include "uart/uart.hpp"
constexpr auto READ_FLASH_CMD = 'f';
constexpr auto WRITE_FLASH_CMD = 'F';
constexpr auto READ_EEPROM_CMD = 'e';
constexpr auto WRITE_EEPROM_CMD = 'E';
constexpr auto READ_USERDATA_CMD = 'c';
constexpr auto WRITE_USERDATA_CMD = 'C';
constexpr auto REQUEST_CMD = '?';
constexpr auto CONFIRM_CMD = '!';
constexpr auto AUTO_BAUDING_CMD = '@';
using uart_interface = uart::Hardware0<uart::Config<115200>, uart::Driven::BLOCKING>;
enum class State {
WAITING,
ACTIVE,
};
struct DeviceInfo {
char name[3] = {'T', 'S', 'B'};
uint8_t date[2] = {0x1a, 0x1f};
uint8_t status = 0xf0;
uint8_t signature[3] = {0x1e, 0x95, 0x0f};
uint8_t pageSize = 0x40;
uint16_t flashSize = 0x3ec0;
uint16_t eepromSize = 0x03ff;
};
struct UserData {
uint16_t jumpAddress = 0xAAAA;
uint8_t timeout = 0x21;
};
static inline void sendDeviceInfo()
{
uart::Uart<uart_interface> serial;
constexpr DeviceInfo deviceInfo;
constexpr UserData userData;
for (uint8_t i = 0; i < sizeof(deviceInfo); ++i) {
serial.txByte(*(reinterpret_cast<const uint8_t *>(&deviceInfo) + i));
}
for (uint8_t i = 0; i < sizeof(userData); ++i) {
serial.txByte(*(reinterpret_cast<const uint8_t *>(&userData) + i));
}
}
static uint8_t g_lastPage[128] = {};
static inline void sendUserData()
{
uart::Uart<uart_interface> serial;
for (uint8_t i = 0; i < sizeof(g_lastPage); ++i) {
serial.txByte(*(reinterpret_cast<const uint8_t *>(&g_lastPage) + i));
}
}
static inline void sendConfirm()
{
uart::Uart<uart_interface> serial;
serial.txByte(CONFIRM_CMD);
}
int main()
{
uart::Uart<uart_interface> serial;
serial.init();
State state = State::WAITING;
uint8_t receivedByte = 0;
uint8_t autoBaudingCounter = 0;
while (true) {
if (serial.rxByte(receivedByte)) {
if (state == State::WAITING) {
if (receivedByte == AUTO_BAUDING_CMD) {
++autoBaudingCounter;
}
if (autoBaudingCounter == 3) {
autoBaudingCounter = 0;
state = State::ACTIVE;
sendDeviceInfo();
}
} else if (state == State::ACTIVE) {
if (receivedByte == READ_USERDATA_CMD) {
sendUserData();
sendConfirm();
state = State::WAITING;
}
}
}
}
return 0;
}

256
tsb/tsb.cppproj
View File

@@ -1,256 +0,0 @@
<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="14.0">
<PropertyGroup>
<SchemaVersion>2.0</SchemaVersion>
<ProjectVersion>7.0</ProjectVersion>
<ToolchainName>com.Atmel.AVRGCC8.CPP</ToolchainName>
<ProjectGuid>dce6c7e3-ee26-4d79-826b-08594b9ad897</ProjectGuid>
<avrdevice>ATmega328P</avrdevice>
<avrdeviceseries>none</avrdeviceseries>
<OutputType>Executable</OutputType>
<Language>CPP</Language>
<OutputFileName>$(MSBuildProjectName)</OutputFileName>
<OutputFileExtension>.elf</OutputFileExtension>
<OutputDirectory>$(MSBuildProjectDirectory)\$(Configuration)</OutputDirectory>
<AssemblyName>tsb</AssemblyName>
<Name>tsb</Name>
<RootNamespace>tsb</RootNamespace>
<ToolchainFlavour>avr-g++-9.1.0</ToolchainFlavour>
<KeepTimersRunning>true</KeepTimersRunning>
<OverrideVtor>false</OverrideVtor>
<CacheFlash>true</CacheFlash>
<ProgFlashFromRam>true</ProgFlashFromRam>
<RamSnippetAddress>0x20000000</RamSnippetAddress>
<UncachedRange />
<preserveEEPROM>true</preserveEEPROM>
<OverrideVtorValue>exception_table</OverrideVtorValue>
<BootSegment>2</BootSegment>
<ResetRule>0</ResetRule>
<eraseonlaunchrule>0</eraseonlaunchrule>
<EraseKey />
<avrtool>com.atmel.avrdbg.tool.atmelice</avrtool>
<avrtoolserialnumber>J41800099437</avrtoolserialnumber>
<avrdeviceexpectedsignature>0x1E950F</avrdeviceexpectedsignature>
<com_atmel_avrdbg_tool_stk500>
<ToolOptions>
<InterfaceProperties>
<IspClock>125000</IspClock>
</InterfaceProperties>
<InterfaceName>ISP</InterfaceName>
</ToolOptions>
<ToolType>com.atmel.avrdbg.tool.stk500</ToolType>
<ToolNumber>
</ToolNumber>
<ToolName>STK500</ToolName>
</com_atmel_avrdbg_tool_stk500>
<avrtoolinterface>ISP</avrtoolinterface>
<avrtoolinterfaceclock>125000</avrtoolinterfaceclock>
<AsfFrameworkConfig>
<framework-data xmlns="">
<options />
<configurations />
<files />
<documentation help="" />
<offline-documentation help="" />
<dependencies>
<content-extension eid="atmel.asf" uuidref="Atmel.ASF" version="3.47.0" />
</dependencies>
</framework-data>
</AsfFrameworkConfig>
<com_atmel_avrdbg_tool_atmelice>
<ToolOptions>
<InterfaceProperties>
<IspClock>125000</IspClock>
</InterfaceProperties>
<InterfaceName>ISP</InterfaceName>
</ToolOptions>
<ToolType>com.atmel.avrdbg.tool.atmelice</ToolType>
<ToolNumber>J41800099437</ToolNumber>
<ToolName>Atmel-ICE</ToolName>
</com_atmel_avrdbg_tool_atmelice>
<custom>
<ToolOptions>
<InterfaceProperties>
<IspClock>125000</IspClock>
</InterfaceProperties>
<InterfaceName>
</InterfaceName>
</ToolOptions>
<ToolType>custom</ToolType>
<ToolNumber>
</ToolNumber>
<ToolName>Custom Programming Tool</ToolName>
</custom>
<com_atmel_avrdbg_tool_simulator>
<ToolOptions xmlns="">
<InterfaceProperties>
</InterfaceProperties>
<InterfaceName>
</InterfaceName>
</ToolOptions>
<ToolType xmlns="">com.atmel.avrdbg.tool.simulator</ToolType>
<ToolNumber xmlns="">
</ToolNumber>
<ToolName xmlns="">Simulator</ToolName>
</com_atmel_avrdbg_tool_simulator>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
<ToolchainSettings>
<AvrGccCpp>
<avrgcc.common.Device>-mmcu=atmega328p</avrgcc.common.Device>
<avrgcc.common.outputfiles.hex>True</avrgcc.common.outputfiles.hex>
<avrgcc.common.outputfiles.lss>True</avrgcc.common.outputfiles.lss>
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401
tsb/tsb_asm.cpp Normal file
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// TinySafeBoot on libavr - tier 3: full feature parity in the 512-byte boot
// section, in C++ except where the C ABI itself is the cost.
//
// The complete TinySafeBoot feature set - watchdog-reset bail, one-wire
// half-duplex UART, a config-page activation timeout, the password gate,
// emergency erase, and config/flash/EEPROM read-write - inside the 512-byte
// BOOTSZ=11 section the hand-written oracle occupies (oracle/README.md holds
// what each tier measures, in one table rather than four). The
// body is the tricks tier's C++ (same register protocol, same structure - see
// tsb_tricks.cpp, including the global-register miscompile rules) with exactly
// two routines kept in assembly, the two whose remaining cost *is* the calling
// convention:
//
// rx the bounded receive: C++ must re-floor the timeout window on every
// call (the global-register-store miscompile) and split it across
// call-saved registers; the asm keeps the oracle's X-register nested
// countdown.
// store the page-store loop: C++ cannot hold the receive byte pair and the
// walked Z pointer across the rx calls without call-saved staging
// (push/pop + a Y->Z copy per word); the asm calls rx knowing exactly
// which registers it touches and walks Z live across the whole page.
//
// Everything else - bring-up, activation, password gate, emergency erase,
// dispatch, every SPM/EEPROM/flash primitive, every geometry/baud/info
// constant - is C++ on libavr, and the two asm routines splice into the same
// global-register protocol the C++ uses (g_addr in Y, g_cnt in r16, g_window
// in r7, g_receiving in r6), so calls cross the boundary with no marshalling.
//
// The wire protocol is strict request/response, which is what makes the shared
// line safe: the device drives it only between a received command and its
// reply, and releases it (RXEN0 only) whenever it waits.
#include <libavr/libavr.hpp>
#include <avr/io.h> // SP / RAMEND for the crt-free boot entry, SFR addresses for the asm routines
using namespace avr::literals;
namespace spm = avr::spm;
namespace ee = avr::eeprom;
namespace hw = avr::hw;
namespace tsb {
namespace {
// The loader is purely polled - it never enables interrupts - so every SPM and
// EEPROM lock folds to nothing under this posture.
constexpr auto off = avr::irq::guard_policy::unused;
// Strict request/response: every SPM operation is waited out before the next
// byte moves, so no flash operation is ever in flight at an EEPROM access -
// the write procedure's step 2 has nothing to guard, the omission the
// datasheet grants (DS40002061B section 8.6.3).
constexpr auto no_spm = ee::spm_interlock::omitted;
constexpr std::uint8_t confirm = '!';
constexpr std::uint8_t request = '?';
constexpr std::uint8_t knock = '@';
// Boot geometry for the 512 B boot section (BOOTSZ=11); the page size and the
// flash/EEPROM extents are the chip database's to know. app_end is the config
// page (TSB's LASTPAGE), one page below the boot section.
constexpr std::uint16_t page = spm::page_bytes;
constexpr std::uint16_t boot_bytes = 512;
constexpr std::uint16_t app_end = spm::flash_bytes - boot_bytes - page;
constexpr std::uint16_t eeprom_end = avr::hw::db.mem.eeprom_size - 1;
// Lockout-proof floor for the activation window: the oracle's F_CPU/1MHz, so
// it follows the clock rather than restating it (rule 41).
constexpr auto act_min = static_cast<std::uint8_t>((16_MHz).hz / 1'000'000);
// Post-activation window: the host gets seconds, not milliseconds, mid-session.
constexpr std::uint8_t comm_window = 200;
constexpr std::uint16_t build_date = 26 * 512 + 7 * 32 + 20;
// Fixed 115200 8N1; the library solves UBRR + U2X from clock and baud.
constexpr auto baud = avr::uart::solve_baud(16_MHz, 115200_Bd, 8, avr::uart::parity::none);
// One bit time on the wire: the turn-around a shared-line peer needs to stop
// driving before this one starts. Derived from the solved rate, so it follows
// the link rather than a count measured against one.
constexpr auto guard_cycles = static_cast<std::uint32_t>((16_MHz).hz / baud.actual);
// The 16-byte device-info block, streamed out on activation.
// clang-format off
[[gnu::progmem]] constexpr auto info = std::to_array<std::uint8_t>({
'T', 'S', 'B',
build_date & 0xFF, build_date >> 8,
0xF3, // status: native-UART fixed-baud lineage
avr::hw::db.signature[0], avr::hw::db.signature[1], avr::hw::db.signature[2],
page / 2, // page size in words
(app_end / 2) & 0xFF, (app_end / 2) >> 8,
eeprom_end & 0xFF, eeprom_end >> 8,
0xAA, 0xAA,
});
// clang-format on
register std::uint16_t g_addr asm("r28");
register std::uint8_t g_cnt asm("r16");
register std::uint8_t g_window asm("r7");
register std::uint8_t g_receiving asm("r6");
const std::uint8_t *flash_ptr(std::uint16_t addr)
{
return reinterpret_cast<const std::uint8_t *>(addr);
}
// Bounded byte receive (asm 1 of 2): release the one-wire line on a direction
// change, poll RXC0 under the oracle's nested X-register countdown seeded from
// g_window (floored against lockout), byte or 0-on-silence in r24. Z survives
// - the property the store's word loop rides on.
[[gnu::noinline, gnu::noclone]] std::uint8_t rx()
{
std::uint8_t byte;
asm volatile(" tst %[dir] \n\t" // already receiving? keep the line released
" brne 1f \n\t"
" ldi %[b], 0x10 \n\t" // RXEN0 alone: release the line and listen
" sts %[ucsr0b], %[b] \n\t"
" ser %[b] \n\t"
" mov %[dir], %[b] \n\t"
"1: mov r27, %[to] \n\t" // outer countdown high byte = window
" ori r27, %[actmin] \n\t" // lockout-proof floor
" clr r26 \n\t"
"2: ser %[b] \n\t"
"3: lds %[b], %[ucsr0a] \n\t"
" sbrc %[b], 7 \n\t" // RXC0
" rjmp 4f \n\t"
" dec %[b] \n\t"
" brne 3b \n\t"
" sbiw r26, 1 \n\t"
" brcc 2b \n\t"
" clr %[b] \n\t" // silence -> 0, which no compare accepts
" rjmp 5f \n\t"
"4: lds %[b], %[udr0] \n\t"
"5: \n\t"
: [b] "=&d"(byte), [dir] "+r"(g_receiving)
: [to] "r"(g_window), [actmin] "M"(act_min), [ucsr0a] "n"(_SFR_MEM_ADDR(UCSR0A)),
[ucsr0b] "n"(_SFR_MEM_ADDR(UCSR0B)), [udr0] "n"(_SFR_MEM_ADDR(UDR0))
: "r26", "r27", "cc");
return byte;
}
// One-wire transmit: take the line (TXEN0 alone) on a direction change with a
// turn-around guard, put the byte out, hold the line until the whole frame is
// out (TXC0, not UDRE0), W1C TXC0 by storing the sampled status back (keeps
// U2X0). Plain C++ - it compiles *smaller* than the oracle's routine.
[[gnu::noinline, gnu::noclone]] void tx(std::uint8_t byte)
{
if (g_receiving) {
g_receiving = 0;
hw::ucsr0b::write(hw::ucsr0b::txen0(1));
avr::delay::cycles<guard_cycles>();
}
hw::udr0::write(byte);
std::uint8_t status;
do {
status = hw::ucsr0a::read();
} while (!(status & hw::ucsr0a::txc0(1).value));
hw::ucsr0a::write(status);
}
// '?', then hand back the host's reply for the callers' one-byte compare.
[[gnu::noinline, gnu::noclone]] std::uint8_t rcnf()
{
tx(request);
return rx();
}
// One flash byte <- [g_addr++] (the advance right before ret - the
// global-register rule, see tsb_tricks.cpp).
[[gnu::noinline, gnu::noclone]] std::uint8_t sflash()
{
std::uint8_t byte = avr::flash_load(flash_ptr(g_addr));
++g_addr;
return byte;
}
// One EEPROM byte <- [g_addr++].
[[gnu::noinline, gnu::noclone]] std::uint8_t eerd()
{
std::uint8_t byte = ee::read<no_spm>(g_addr);
++g_addr;
return byte;
}
// One EEPROM byte -> [g_addr++].
[[gnu::noinline, gnu::noclone]] void eewr(std::uint8_t byte)
{
ee::write<off, no_spm>(g_addr, byte);
++g_addr;
}
// Stream g_cnt flash bytes from g_addr to the host.
[[gnu::noinline, gnu::noclone]] void sendf()
{
do {
tx(sflash());
} while (--g_cnt);
}
// Wait out a running SPM op, then re-open the RWW section - after every page
// op and before handing over, as the oracle does.
[[gnu::noinline, gnu::noclone]] void settle()
{
spm::wait();
spm::rww_enable<off>();
}
extern "C" [[noreturn]] void tsb_app(); // the application's reset vector: --defsym=tsb_app=0
[[noreturn]] void appjump()
{
settle();
tsb_app();
}
// Step g_addr one page down and erase that page (the decrement lives here -
// the global-register rule).
[[gnu::noinline, gnu::noclone]] void erase_below()
{
g_addr -= page;
spm::command<off>(spm::op::erase, g_addr);
settle();
}
// Erase the whole application, top-down like the oracle: the loop bound is a
// compare with zero, and g_addr = 0 is handed back for free.
[[gnu::noinline, gnu::noclone]] void erase_application()
{
g_addr = app_end;
do {
erase_below();
} while (g_addr != 0);
}
// Stream one host page into the erased flash page at g_addr (asm 2 of 2): the
// word pair stages in r0:r1 straight from rx (whose register set is known -
// the cross-call liveness C++ cannot express), Z walks the page and PGWRT
// programs it. g_addr is left at the next page base.
[[gnu::noinline, gnu::noclone]] void store_flash()
{
asm volatile(" movw r30, r28 \n\t" // Z = page base; rx leaves Z live
" ldi r20, %[words] \n\t"
"1: rcall %x[rx] \n\t"
" mov r0, r24 \n\t" // word low byte
" rcall %x[rx] \n\t"
" mov r1, r24 \n\t" // word high byte
" ldi r24, 0x01 \n\t" // SPMEN: buffer the word at Z
" out %[spmcsr], r24 \n\t"
" spm \n\t"
" clr r1 \n\t"
" adiw r30, 2 \n\t"
" dec r20 \n\t"
" brne 1b \n\t"
" movw %[base], r30 \n\t" // g_addr = the next page base
" subi r30, %[pagelo] \n\t" // Z back to this page's base
" sbci r31, %[pagehi] \n\t"
" ldi r24, 0x05 \n\t" // PGWRT | SPMEN: program the page
" out %[spmcsr], r24 \n\t"
" spm \n\t"
: [base] "+r"(g_addr)
: [rx] "i"(&rx), [spmcsr] "I"(_SFR_IO_ADDR(SPMCSR)), [words] "M"(page / 2), [pagelo] "M"(page & 0xff),
[pagehi] "M"(page >> 8)
: "r0", "r1", "r20", "r24", "r26", "r27", "r30", "r31", "cc", "memory");
settle();
}
[[noreturn, gnu::noinline]] void run()
{
// A watchdog reset hands straight back to the application, as the
// reference loader does, rather than re-entering the bootloader.
if (hw::mcusr::wdrf.test()) {
appjump();
}
// Lean bring-up from reset state: UCSR0C already reads 8N1, UBRR0H reads
// 0, and rx()/tx() raise RXEN0/TXEN0 on first use - only the divisor low
// byte and U2X0 need a store. The library still does the datasheet work.
static_assert(baud.u2x && baud.ubrr < 256, "lean bring-up writes UBRR0L only, with U2X0");
hw::ubrr0::write(static_cast<std::uint8_t>(baud.ubrr));
hw::ucsr0a::write(hw::ucsr0a::u2x0(1));
// General-purpose registers are undefined at power-on (no crt zeroes them);
// the direction latch must start "not receiving" so the first rx() enables
// the receiver. The reference loader clears its shadow register for the
// same reason.
g_receiving = 0;
// Activation: 3x'@', each inside the config page's timeout window (rx
// floors it so a corrupt page cannot lock the loader out); anything else -
// including silence - hands over.
g_window = avr::flash_load(flash_ptr(app_end + 2));
for (std::uint8_t k = 3; k; --k) {
if (rx() != knock) {
appjump();
}
}
g_window = comm_window;
// Password gate (config page from app_end+3, 0xff-terminated; a blank
// page is no password). A wrong byte blanks the comparison and drains the
// line forever, so a wrong password can never fall through; a 0 requests
// emergency erase behind two confirms. On pass the info block goes out;
// the emergency path skips it and drops into the command loop.
g_addr = app_end + 3;
std::uint8_t mask = 0xff;
for (;;) {
std::uint8_t expected = avr::flash_load(flash_ptr(g_addr)) & mask;
++g_addr;
if (expected == 0xff) {
g_addr = reinterpret_cast<std::uint16_t>(info.data());
g_cnt = sizeof(info);
sendf();
break;
}
std::uint8_t got = rx();
if (got == 0) {
if (mask == 0) {
continue;
}
if (rcnf() != confirm || rcnf() != confirm) {
appjump();
}
erase_application(); // leaves g_addr = 0 for the EEPROM walk
do {
eewr(0xff);
} while (g_addr <= eeprom_end);
g_addr = app_end + page;
erase_below();
break;
}
if (got != expected) {
mask = 0;
}
}
for (;;) {
tx(confirm); // Mainloop ready
g_addr = 0;
switch (rx()) {
case 'f': // read application flash, one page per host '!'
for (;;) {
if (rx() != confirm) {
break;
}
g_cnt = page;
sendf();
if (g_addr >= app_end) {
break;
}
}
break;
case 'F': // erase the application, then take pages behind '?'
erase_application(); // leaves g_addr = 0, the write start
while (rcnf() == confirm) {
store_flash();
}
break;
case 'e': // read EEPROM, one page per host '!', until the host stops
for (;;) {
if (rx() != confirm) {
break;
}
g_cnt = page;
do {
tx(eerd());
} while (--g_cnt);
}
break;
case 'E': // take EEPROM pages behind '?'
while (rcnf() == confirm) {
g_cnt = page;
do {
eewr(rx());
} while (--g_cnt);
}
break;
case 'c': // read the config page
read_config:
g_addr = app_end;
g_cnt = page;
sendf();
break;
case 'C': // replace the config page, then echo it back to verify
if (rcnf() != confirm) {
break;
}
g_addr = app_end + page;
erase_below(); // leaves g_addr = app_end, the store target
store_flash();
goto read_config;
default: // 'q' or any other byte runs the application
appjump();
}
}
}
} // namespace
} // namespace tsb
// Reset lands at the boot section base (BOOTRST): the entry stub in .vectors
// is laid first and does the one line of crt a crt-less image needs.
template struct avr::startup::entry<tsb::run, avr::startup::stack::hardware>;

329
tsb/tsb_policy.cpp Normal file
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@@ -0,0 +1,329 @@
// TinySafeBoot on libavr - the policy floor: pureboot's rules, measured.
//
// The full TinySafeBoot feature set - watchdog bail, one-wire half-duplex,
// config-page activation timeout, password gate, emergency erase, and
// config/flash/EEPROM read-write - under philosophy #5 exactly as pureboot
// obeys it: no assembly, no register variables; code, attributes, and flags
// only. Every lesson pureboot's development produced is applied - the
// library's half-duplex serial and startup entry, lean bring-up from reset
// state, one merged send loop over both memories, oracle-shaped loop bounds,
// locals threaded through noinline primitives, pureboot's codegen flags -
// and the result sits below the idiomatic tier and above the 512 B boot
// section the tricks/asm tiers reach with the banned mechanisms
// (oracle/README.md holds all four). This tier exists to keep that gap an
// artifact
// rather than a claim: the gap to 512 is the rent of policy-clean C++ -
// helpers that hold a cursor across rx()/tx() pay push/pop and argument
// threading where a global-register protocol pays nothing, and both
// control-flow merges tried (a parametrized paged session, a merged store
// loop) measured larger than the split cases they replaced. TSB's wire fixes
// the per-command loop shapes on the device, so pureboot 5's one-transfer-
// loop collapse has no purchase here.
//
// The wire protocol is strict request/response, which is what makes the
// shared line safe: the device drives it only between a received command and
// its reply, and releases it (the library's half-duplex choreography)
// whenever it waits.
#include <libavr/libavr.hpp>
using namespace avr::literals;
namespace spm = avr::spm;
namespace ee = avr::eeprom;
using dev = avr::device<{.clock = 16_MHz}>;
// One-wire: RX and TX share the line, exactly as the native-UART TSB expects.
// 115200 at 16 MHz lands +2.1 % off, past the receiver-tolerance table the
// solver holds rates to - the oracle's own deployment has run there for a
// decade, so the override states that it is meant.
using serial_t = dev::uart0<{
.baud = 115200_Bd,
.allow_baud_error = true,
.half_duplex = true,
}>;
inline constexpr serial_t serial{};
namespace tsb {
namespace {
// The loader is purely polled - it never enables interrupts - so every SPM and
// EEPROM lock folds to nothing under this posture.
constexpr auto off = avr::irq::guard_policy::unused;
// Strict request/response: every SPM operation is waited out before the next
// byte moves, so no flash operation is ever in flight at an EEPROM access -
// the write procedure's step 2 has nothing to guard, the omission the
// datasheet grants (DS40002061B section 8.6.3).
constexpr auto no_spm = ee::spm_interlock::omitted;
// The handshake bytes, identical across every TSB host.
constexpr std::uint8_t confirm = '!';
constexpr std::uint8_t request = '?';
constexpr std::uint8_t knock = '@';
// Boot geometry for the 1 KB boot section (BOOTSZ=10); the page size and the
// flash/EEPROM extents are the chip database's to know. app_end is the config
// page (TSB's LASTPAGE), one page below the boot section.
constexpr std::uint16_t page = spm::page_bytes;
constexpr std::uint16_t boot_bytes = 1024;
constexpr std::uint16_t app_end = spm::flash_bytes - boot_bytes - page;
constexpr std::uint16_t eeprom_end = avr::hw::db.mem.eeprom_size - 1;
// Lockout-proof floor for the activation window: the oracle's F_CPU/1MHz, so
// it follows the clock rather than restating it (rule 41).
constexpr auto act_min = static_cast<std::uint8_t>(dev::clock.hz / 1'000'000);
// Post-activation window: the host gets seconds, not milliseconds, mid-session.
constexpr std::uint8_t comm_window = 200;
// Firmware version stamp: YY*512 + MM*32 + DD, the encoding the host decodes.
constexpr std::uint16_t build_date = 26 * 512 + 7 * 32 + 27;
// The 16-byte device-info block, streamed out on activation.
// clang-format off
[[gnu::progmem]] constexpr auto info = std::to_array<std::uint8_t>({
'T', 'S', 'B',
build_date & 0xFF, build_date >> 8,
0xF3, // status: native-UART fixed-baud lineage
avr::hw::db.signature[0], avr::hw::db.signature[1], avr::hw::db.signature[2],
page / 2, // page size in words
(app_end / 2) & 0xFF, (app_end / 2) >> 8, // app-flash boundary, words
eeprom_end & 0xFF, eeprom_end >> 8,
0xAA, 0xAA, // ATmega processor-type marker (bytes 14 == 15)
});
// clang-format on
// The receive window, pre-floored where it is set. In .noinit: there is no
// crt to clear a .bss image, and run() stores it before the first receive.
[[gnu::section(".noinit")]] std::uint8_t window;
const std::uint8_t *flash_ptr(std::uint16_t addr)
{
return reinterpret_cast<const std::uint8_t *>(addr);
}
// Bounded byte receive: poll under nested countdowns, 0 on silence. The 0
// then falls through every compare - not a knock, not a confirm, not a
// command - so a silent host unwinds the loader to the application from
// anywhere, and a mid-session cable pull cannot wedge it. The line release on
// a direction change is the serial backend's.
[[gnu::noinline]] std::uint8_t rx()
{
std::uint16_t outer = static_cast<std::uint16_t>(window) << 8;
do {
std::uint8_t fine = 0;
do {
if (auto byte = serial.read()) {
return *byte;
}
} while (--fine);
} while (--outer);
return 0;
}
// One-wire transmit: the backend takes the line with a turn-around guard and
// holds it until the whole frame is out.
[[gnu::noinline]] void tx(std::uint8_t byte)
{
serial.write(byte);
}
// '?', then hand back the host's reply for the callers' one-byte compare.
[[gnu::noinline]] std::uint8_t rcnf()
{
tx(request);
return rx();
}
// The one send loop: the info block, the config page, application flash and
// EEPROM pages all stream through here.
[[gnu::noinline]] void send_block(bool eep, std::uint16_t at, std::uint8_t count)
{
do {
tx(eep ? ee::read<no_spm>(at) : avr::flash_load(flash_ptr(at)));
++at;
} while (--count);
}
// One EEPROM byte in - shared by the emergency wipe and the 'E' stream.
[[gnu::noinline]] void eeput(std::uint16_t at, std::uint8_t value)
{
ee::write<off, no_spm>(at, value);
}
// Wait out a running SPM op, then re-open the RWW section - after every page
// op and before handing over, as the oracle does.
[[gnu::noinline]] void settle()
{
spm::wait();
spm::rww_enable<off>();
}
// One host page straight into the erased flash page at `at` - through the SPM
// word buffer (low byte then high), no SRAM staging - then committed. `at`
// names a page base, so the cursor's low byte reaching the boundary ends the
// walk.
[[gnu::noinline]] void store_flash_page(std::uint16_t at)
{
const auto open = spm::page::begin<spm::from::boot_section, off>(at);
do {
std::uint8_t low = rx();
std::uint8_t high = rx();
spm::fill<off>(open, at, std::bit_cast<std::uint16_t>(std::array{low, high}));
at += 2;
} while (static_cast<std::uint8_t>(at) & (page - 1));
spm::command<off>(spm::op::write, at - page);
settle();
}
extern "C" [[noreturn]] void tsb_app(); // the application's reset vector: --defsym=tsb_app=0
[[noreturn]] void appjump()
{
settle();
tsb_app();
}
// Step one page down and erase it - the erase shared by the whole-app walk,
// the config rewrite and the emergency wipe; hands the stepped address back.
[[gnu::noinline]] std::uint16_t erase_below(std::uint16_t at)
{
at -= page;
spm::command<off>(spm::op::erase, at);
settle();
return at;
}
// Erase the whole application, top-down like the oracle: the loop bound is a
// compare with zero, and the returned 0 is the address every caller wants
// next.
[[gnu::noinline]] std::uint16_t erase_application()
{
std::uint16_t at = app_end;
do {
at = erase_below(at);
} while (at != 0);
return at;
}
[[noreturn]] void run()
{
// A watchdog reset hands straight back to the application, as the
// reference loader does, rather than re-entering the bootloader.
if (avr::hw::mcusr::wdrf.test()) {
appjump();
}
// Lean bring-up from reset state: UCSR0C already reads 8N1, UBRR0H reads
// 0, and the half-duplex write()/read() raise TXEN0/RXEN0 on first use -
// only the divisor low byte and U2X0 need a store. The solver still does
// the datasheet work; the asserts pin the reset-state assumptions.
{
constexpr auto sol = avr::uart::solve_baud(dev::clock, 115200_Bd, 8, avr::uart::parity::none);
static_assert(sol.u2x && sol.ubrr < 256, "lean bring-up writes UBRR0L only, with U2X0");
avr::hw::ubrr0::write(static_cast<std::uint8_t>(sol.ubrr));
avr::hw::ucsr0a::write(avr::hw::ucsr0a::u2x0(1));
}
// Activation: 3x'@', each inside the config page's timeout window
// (floored so a corrupt page cannot lock the loader out); anything else -
// including silence - hands over.
window = avr::flash_load(flash_ptr(app_end + 2)) | act_min;
for (std::uint8_t k = 3; k; --k) {
if (rx() != knock) {
appjump();
}
}
window = comm_window;
// Password gate (config page from app_end+3, 0xff-terminated; a blank
// page is no password). A wrong byte blanks the comparison and drains the
// line forever, so a wrong password can never fall through; a 0 requests
// emergency erase behind two confirms. On pass the info block goes out;
// the emergency path skips it and drops into the command loop.
std::uint16_t at = app_end + 3;
std::uint8_t mask = 0xff;
for (;;) {
std::uint8_t expected = avr::flash_load(flash_ptr(at)) & mask;
++at;
if (expected == 0xff) {
send_block(false, reinterpret_cast<std::uint16_t>(info.data()), info.size());
break;
}
std::uint8_t got = rx();
if (got == 0) {
if (mask == 0) {
continue;
}
if (rcnf() != confirm || rcnf() != confirm) {
appjump();
}
std::uint16_t a = erase_application();
do {
eeput(a, 0xff);
} while (++a <= eeprom_end);
erase_below(app_end + page);
break;
}
if (got != expected) {
mask = 0;
}
}
for (;;) {
tx(confirm); // Mainloop ready
const std::uint8_t command = rx();
switch (command) {
case 'f': // read application flash, one page per host '!'
for (std::uint16_t a = 0; a < app_end; a += page) {
if (rx() != confirm) {
break;
}
send_block(false, a, page);
}
break;
case 'e': // read EEPROM, one page per host '!', until the host stops
for (std::uint16_t a = 0;; a += page) {
if (rx() != confirm) {
break;
}
send_block(true, a, page);
}
break;
case 'F': { // erase the application, then take pages behind '?'
std::uint16_t a = erase_application();
for (; rcnf() == confirm; a += page) {
store_flash_page(a);
}
break;
}
case 'E': // take EEPROM pages behind '?', each write host-paced
for (std::uint16_t a = 0; rcnf() == confirm;) {
std::uint8_t count = page;
do {
eeput(a, rx());
++a;
} while (--count);
}
break;
case 'c': // read the config page
read_config:
send_block(false, app_end, page);
break;
case 'C': // replace the config page, then echo it back to verify
if (rcnf() != confirm) {
break;
}
store_flash_page(erase_below(app_end + page));
goto read_config;
default: // 'q' or any other byte runs the application
appjump();
}
}
}
} // namespace
} // namespace tsb
// Reset lands at the boot section base (BOOTRST): the entry stub in .vectors
// is laid first and does the one line of crt a crt-less image needs.
template struct avr::startup::entry<tsb::run, avr::startup::stack::hardware>;

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// TinySafeBoot on libavr - tier 1: pure, idiomatic C++.
//
// A serial flash bootloader for the ATmega328P boot section, reimplementing the
// TinySafeBoot native-UART fixed-baud protocol on libavr with the full feature
// set of the hand-written oracle: a watchdog-reset bail, one-wire half-duplex,
// a config-page activation timeout, the password gate, emergency erase, and
// config/flash/EEPROM read-write. This variant is written for clarity -
// well-factored functions, no compiler-specific size hacks, no inline assembly.
// The one-wire wiring, the flash-resident info block and every SPM/EEPROM lock
// are libavr's to handle; the only attribute is the naked reset entry that
// stands in for the absent C runtime.
#include <libavr/libavr.hpp>
#include <avr/io.h> // SP / RAMEND for the crt-free boot entry
using namespace avr::literals;
namespace spm = avr::spm;
namespace ee = avr::eeprom;
using dev = avr::device<{.clock = 16_MHz}>;
// One-wire: RX and TX share the line, exactly as the native-UART TSB expects.
// 115200 at 16 MHz lands +2.1 % off, past the receiver-tolerance table the
// solver holds rates to - the oracle's own deployment has run there for a
// decade, so the override states that it is meant.
using serial_t = dev::uart0<{
.baud = 115200_Bd,
.allow_baud_error = true,
.half_duplex = true,
}>;
inline constexpr serial_t serial{};
namespace tsb {
namespace {
// The loader is purely polled - it never enables interrupts - so every SPM and
// EEPROM lock folds to nothing under this posture.
constexpr auto off = avr::irq::guard_policy::unused;
// Strict request/response: every SPM operation is waited out before the next
// byte moves, so no flash operation is ever in flight at an EEPROM access -
// the write procedure's step 2 has nothing to guard, the omission the
// datasheet grants (DS40002061B section 8.6.3).
constexpr auto no_spm = ee::spm_interlock::omitted;
// The handshake bytes, identical across every TSB host.
constexpr std::uint8_t confirm = '!';
constexpr std::uint8_t request = '?';
constexpr std::uint8_t knock = '@';
// Boot geometry for the 1 KB boot section (BOOTSZ=10). The page size and the
// flash/EEPROM extents are the chip database's to know. app_end is the config
// page (the LASTPAGE holding the app-jump vector, activation timeout and
// password), one page below the boot section.
constexpr std::uint16_t page = spm::page_bytes;
constexpr std::uint16_t boot_bytes = 1024;
constexpr std::uint16_t app_end = spm::flash_bytes - boot_bytes - page;
constexpr std::uint16_t eeprom_end = avr::hw::db.mem.eeprom_size - 1;
// Firmware version stamp: YY*512 + MM*32 + DD, the encoding the host decodes.
constexpr std::uint16_t build_date = 26 * 512 + 7 * 32 + 20;
// The 16-byte device-info block the host reads on activation. A flash_table
// keeps it in progmem with no .data image (there is no crt to copy one).
// clang-format off
inline constexpr auto info_data = std::to_array<std::uint8_t>({
'T', 'S', 'B',
build_date & 0xFF, build_date >> 8,
0xF3, // status byte (native-UART fixed-baud lineage)
avr::hw::db.signature[0], avr::hw::db.signature[1], avr::hw::db.signature[2],
page / 2, // page size in words
(app_end / 2) & 0xFF, (app_end / 2) >> 8, // app-flash boundary, words
eeprom_end & 0xFF, eeprom_end >> 8,
0xAA, 0xAA, // ATmega processor-type marker (bytes 14 == 15)
});
// clang-format on
using info = avr::flash_table<info_data>;
// The lockout-proof floor for the receive window: the oracle's F_CPU/1MHz, so
// it follows the clock rather than restating it.
constexpr auto act_min = static_cast<std::uint8_t>(dev::clock.hz / 1'000'000);
// The receive window, pre-floored where it is set. In .noinit: there is no crt
// to clear a .bss image, and run() stores it before the first receive.
[[gnu::section(".noinit")]] std::uint8_t window;
// Bounded byte read over the one-wire line - read() releases the line to the
// receiver - answering 0 on silence. That 0 falls through every compare below:
// not a knock, not a confirm, not a command, so a silent host unwinds the
// loader to the application from anywhere and a mid-session cable pull cannot
// wedge it. The oracle lists that timeout among its own fixes, and a blocking
// read is how a tier loses it.
std::uint8_t rx()
{
std::uint16_t outer = static_cast<std::uint16_t>(window) << 8;
do {
std::uint8_t fine = 0;
do {
if (auto byte = serial.read()) {
return *byte;
}
} while (--fine);
} while (--outer);
return 0;
}
// write() takes the line and holds it until the frame is out.
void tx(std::uint8_t byte)
{
serial.write(byte);
}
const std::uint8_t *flash_ptr(std::uint16_t addr)
{
return reinterpret_cast<const std::uint8_t *>(addr);
}
// Stream `count` bytes to the host, from flash (LPM) or from EEPROM.
void send_flash(std::uint16_t addr, std::uint8_t count)
{
while (count--) {
tx(avr::flash_load(flash_ptr(addr++)));
}
}
void send_eeprom(std::uint16_t addr, std::uint8_t count)
{
while (count--) {
tx(ee::read<no_spm>(addr++));
}
}
// Prompt the host with '?' and report whether it answered '!'.
bool request_confirm()
{
tx(request);
return rx() == confirm;
}
// Stream one page from the host straight into the already-erased flash page at
// `addr`, filling the SPM word buffer low byte then high - no SRAM staging, so
// receiving and programming are the same loop.
void store_flash_page(std::uint16_t addr)
{
const auto open = spm::page::begin<spm::from::boot_section, off>(addr);
for (std::uint16_t i = 0; i < page; i += 2) {
std::uint8_t lo = rx();
std::uint8_t hi = rx();
spm::fill<off>(open, addr + i, static_cast<std::uint16_t>(lo | (hi << 8)));
}
spm::write_page<spm::from::boot_section, off>(addr); // blocking: waits the write out
}
// Stream one page from the host straight into EEPROM, byte by byte.
void store_eeprom_page(std::uint16_t addr)
{
for (std::uint16_t i = 0; i < page; ++i) {
ee::write<off, no_spm>(addr + i, rx());
}
}
// Erase one flash page, waited out by the blocking spelling - the erase step
// shared by the whole-app erase, the config-page rewrite and the emergency
// wipe.
void erase_page(std::uint16_t addr)
{
spm::erase_page<spm::from::boot_section, off>(addr);
}
// Erase the whole application, one page at a time, top-down as the reference
// loader does (unwritten pages stay erased and the host cannot observe the
// order; the loop bound becomes a compare with zero).
void erase_application()
{
for (std::uint16_t a = app_end; a != 0;) {
a -= page;
erase_page(a);
}
spm::rww_enable<off>();
}
// The application's reset vector; the linker pins it to 0x0000 (--defsym).
extern "C" [[noreturn]] void tsb_app();
// Run the application. Any non-command byte, a wrong password, or an idle
// programmer port lands here.
[[noreturn]] void appjump()
{
spm::wait(); // make sure any pending SPM finished before handing over
tsb_app();
}
// 'f': stream the application flash back, one page per host '!'. Self-terminates
// at the application boundary; the host normally stops earlier with a non-'!'.
void read_flash()
{
for (std::uint16_t a = 0; a < app_end; a += page) {
if (rx() != confirm) {
return;
}
send_flash(a, page);
}
}
// 'e': stream EEPROM back, one page per host '!', until the host stops.
void read_eeprom()
{
for (std::uint16_t a = 0;; a += page) {
if (rx() != confirm) {
return;
}
send_eeprom(a, page);
}
}
// 'F': erase the whole application first, then take pages the host offers
// behind '?'.
void write_flash()
{
erase_application();
for (std::uint16_t a = 0; request_confirm(); a += page) {
store_flash_page(a);
}
}
// 'E': take pages the host offers behind '?' into EEPROM.
void write_eeprom()
{
for (std::uint16_t a = 0; request_confirm(); a += page) {
store_eeprom_page(a);
}
}
// 'C': replace the config page, then echo it back for the host to verify.
void write_config()
{
if (!request_confirm()) {
return;
}
erase_page(app_end);
store_flash_page(app_end);
spm::rww_enable<off>();
send_flash(app_end, page);
}
// Emergency erase: wipe the application flash, the EEPROM and the config page.
// Reachable only from the password gate (a wrong byte can never reach it), so a
// blank config still leaves the loader recoverable.
void emergency_erase()
{
erase_application();
for (std::uint16_t a = 0; a <= eeprom_end; ++a) {
ee::write<off, no_spm>(a, 0xff);
}
erase_page(app_end);
spm::rww_enable<off>();
}
// The password gate. The config page holds the password at app_end+3,
// terminated by 0xff (a blank page means no password). A byte of 0 requests
// emergency erase; a wrong byte hangs the loader, still draining the line, so a
// wrong password can never fall through to the erase.
enum class gate : std::uint8_t { pass, emergency };
gate password_gate()
{
for (const std::uint8_t *pw = flash_ptr(app_end + 3);; ++pw) {
std::uint8_t expected = avr::flash_load(pw);
if (expected == 0xff) {
return gate::pass;
}
std::uint8_t got = rx();
if (got == 0) {
return gate::emergency;
}
if (got != expected) {
for (;;) {
rx();
}
}
}
}
[[noreturn]] void run()
{
// A watchdog reset hands straight back to the application, as the reference
// loader does, rather than re-entering the bootloader.
if (avr::hw::mcusr::wdrf.test()) {
appjump();
}
avr::init<serial_t>();
// Activation: the host knocks three '@' inside a window whose length is the
// config page's timeout byte, floored so a corrupt page can never lock the
// loader out. An idle port times out and boots the application; the same
// window then bounds every receive of the session.
window = avr::flash_load(flash_ptr(app_end + 2)) | act_min;
__uint24 idle = static_cast<__uint24>(window) << 16;
std::uint8_t knocks = 0;
while (knocks < 3) {
if (auto byte = serial.read()) {
knocks = *byte == knock ? knocks + 1 : 0;
} else if (--idle == 0) {
appjump();
}
}
switch (password_gate()) {
case gate::pass:
send_flash(reinterpret_cast<std::uint16_t>(info::storage.data()), info::size());
break;
case gate::emergency:
if (!request_confirm() || !request_confirm()) {
appjump();
}
emergency_erase();
break;
}
for (;;) {
tx(confirm); // Mainloop ready
switch (rx()) {
case 'f':
read_flash();
break;
case 'F':
write_flash();
break;
case 'e':
read_eeprom();
break;
case 'E':
write_eeprom();
break;
case 'c':
send_flash(app_end, page);
break;
case 'C':
write_config();
break;
default:
appjump(); // 'q' or any other byte runs the application
}
}
}
} // namespace
} // namespace tsb
// Reset lands at the boot section base (BOOTRST): the entry stub in .vectors
// is laid first and does the one line of crt a crt-less image needs.
template struct avr::startup::entry<tsb::run, avr::startup::stack::hardware>;

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// TinySafeBoot on libavr - tier 2: C++ with compiler trickery, no assembly.
//
// The full TinySafeBoot feature set - watchdog bail, one-wire half-duplex,
// config-page activation timeout, password gate, emergency erase, and
// config/flash/EEPROM read-write - in pure C++, a little over the 512-byte boot
// section the hand-written oracle fits (oracle/README.md holds what each tier
// measures). The structure mirrors the oracle's: a handful of tiny noinline
// primitives sharing one whole-loader register allocation, expressed as global
// register variables so no helper ever saves, spills, or reloads any of it.
//
// The register protocol (all call-saved, so calls preserve them by ABI):
// Y (r28:r29) g_addr the walked flash/EEPROM address - adiw-able
// r16 g_cnt byte countdown of the running block - ldi-able
// r7 g_window rx timeout, roughly 30 ms units at 16 MHz
// r6 g_receiving one-wire direction latch, cleared at bring-up
// (power-on registers are undefined)
//
// GCC 16.1 miscompiles stores into global register variables: an update whose
// remaining uses all hide inside callees is deleted whenever a CALL follows it
// before any jump/ret (the backend's liveness walk lumps fixed registers with
// call-clobbered ones - minimal repro in libavr's
// test/upstream/gcc-avr-globalreg-repro.cpp). Every
// g_* update below therefore sits where a *local* read or a jump/ret follows
// it - the helpers advance g_addr immediately before returning, and rx()
// re-floors the window on every call instead of storing the floored value
// once. The layout is load-bearing; do not "simplify" it.
//
// The wire protocol is strict request/response, which is what makes the shared
// line safe: the device drives it only between a received command and its
// reply, and releases it (RXEN0 only) whenever it waits.
#include <libavr/libavr.hpp>
#include <avr/io.h> // SP / RAMEND for the crt-free boot entry
using namespace avr::literals;
namespace spm = avr::spm;
namespace ee = avr::eeprom;
namespace hw = avr::hw;
namespace tsb {
namespace {
// The loader is purely polled - it never enables interrupts - so every SPM and
// EEPROM lock folds to nothing under this posture.
constexpr auto off = avr::irq::guard_policy::unused;
// Strict request/response: every SPM operation is waited out before the next
// byte moves, so no flash operation is ever in flight at an EEPROM access -
// the write procedure's step 2 has nothing to guard, the omission the
// datasheet grants (DS40002061B section 8.6.3).
constexpr auto no_spm = ee::spm_interlock::omitted;
constexpr std::uint8_t confirm = '!';
constexpr std::uint8_t request = '?';
constexpr std::uint8_t knock = '@';
// Boot geometry for the 1 KB boot section (BOOTSZ=10); the page size and the
// flash/EEPROM extents are the chip database's to know. app_end is the config
// page (TSB's LASTPAGE), one page below the boot section.
constexpr std::uint16_t page = spm::page_bytes;
constexpr std::uint16_t boot_bytes = 1024;
constexpr std::uint16_t app_end = spm::flash_bytes - boot_bytes - page;
constexpr std::uint16_t eeprom_end = avr::hw::db.mem.eeprom_size - 1;
// Lockout-proof floor for the activation window: the oracle's F_CPU/1MHz, so
// it follows the clock rather than restating it (rule 41).
constexpr auto act_min = static_cast<std::uint8_t>((16_MHz).hz / 1'000'000);
// Post-activation window: the host gets seconds, not milliseconds, mid-session.
constexpr std::uint8_t comm_window = 200;
constexpr std::uint16_t build_date = 26 * 512 + 7 * 32 + 20;
// Fixed 115200 8N1; the library solves UBRR + U2X from clock and baud.
constexpr auto baud = avr::uart::solve_baud(16_MHz, 115200_Bd, 8, avr::uart::parity::none);
// One bit time on the wire: the turn-around a shared-line peer needs to stop
// driving before this one starts. Derived from the solved rate, so it follows
// the link rather than a count measured against one.
constexpr auto guard_cycles = static_cast<std::uint32_t>((16_MHz).hz / baud.actual);
// The 16-byte device-info block, streamed out on activation.
// clang-format off
[[gnu::progmem]] constexpr auto info = std::to_array<std::uint8_t>({
'T', 'S', 'B',
build_date & 0xFF, build_date >> 8,
0xF3, // status: native-UART fixed-baud lineage
avr::hw::db.signature[0], avr::hw::db.signature[1], avr::hw::db.signature[2],
page / 2, // page size in words
(app_end / 2) & 0xFF, (app_end / 2) >> 8,
eeprom_end & 0xFF, eeprom_end >> 8,
0xAA, 0xAA,
});
// clang-format on
register std::uint16_t g_addr asm("r28");
register std::uint8_t g_cnt asm("r16");
register std::uint8_t g_window asm("r7");
register std::uint8_t g_receiving asm("r6");
const std::uint8_t *flash_ptr(std::uint16_t addr)
{
return reinterpret_cast<const std::uint8_t *>(addr);
}
// Bounded byte receive, the oracle's shape: release the one-wire line on a
// direction change, poll RXC0 under nested countdowns, 0 on silence. The 0
// then falls through every compare - not a knock, not a confirm, not a
// command - so a silent host unwinds the loader to the application from
// anywhere, and a mid-session cable pull cannot wedge it.
[[gnu::noinline, gnu::noclone]] std::uint8_t rx()
{
if (!g_receiving) {
g_receiving = 1;
hw::ucsr0b::write(hw::ucsr0b::rxen0(1)); // RXEN0 alone: release and listen
}
// act_min ORs in here, per call, not once into g_window at setup - the
// one placement the global-register-store miscompile cannot delete.
std::uint16_t outer = static_cast<std::uint16_t>(g_window | act_min) << 8;
do {
std::uint8_t fine = 0;
do {
auto status = hw::ucsr0a::read();
if (status & hw::ucsr0a::rxc0(1).value) {
return hw::udr0::read();
}
} while (--fine);
} while (--outer);
return 0;
}
// One-wire transmit: take the line (TXEN0 alone - the receiver must be off
// while driving) on a direction change, with a turn-around guard so a shorted
// peer can switch first; then hold the line until the whole frame is out
// (TXC0, not UDRE0 - the stop bit must be on the wire before a caller may
// release the line), and W1C TXC0 by storing the sampled status back, which
// keeps U2X0.
[[gnu::noinline, gnu::noclone]] void tx(std::uint8_t byte)
{
if (g_receiving) {
g_receiving = 0;
hw::ucsr0b::write(hw::ucsr0b::txen0(1));
avr::delay::cycles<guard_cycles>();
}
hw::udr0::write(byte);
std::uint8_t status;
do {
status = hw::ucsr0a::read();
} while (!(status & hw::ucsr0a::txc0(1).value));
hw::ucsr0a::write(status);
}
// '?', then hand back the host's reply for the callers' one-byte compare.
[[gnu::noinline, gnu::noclone]] std::uint8_t rcnf()
{
tx(request);
return rx();
}
// One flash byte <- [g_addr++] (the advance right before ret - see header).
[[gnu::noinline, gnu::noclone]] std::uint8_t sflash()
{
std::uint8_t byte = avr::flash_load(flash_ptr(g_addr));
++g_addr;
return byte;
}
// One EEPROM byte <- [g_addr++].
[[gnu::noinline, gnu::noclone]] std::uint8_t eerd()
{
std::uint8_t byte = ee::read<no_spm>(g_addr);
++g_addr;
return byte;
}
// One EEPROM byte -> [g_addr++].
[[gnu::noinline, gnu::noclone]] void eewr(std::uint8_t byte)
{
ee::write<off, no_spm>(g_addr, byte);
++g_addr;
}
// Stream g_cnt flash bytes from g_addr to the host.
[[gnu::noinline, gnu::noclone]] void sendf()
{
do {
tx(sflash());
} while (--g_cnt);
}
// Wait out a running SPM op, then re-open the RWW section - after every page
// op and before handing over, as the oracle does.
[[gnu::noinline, gnu::noclone]] void settle()
{
spm::wait();
spm::rww_enable<off>();
}
extern "C" [[noreturn]] void tsb_app(); // the application's reset vector: --defsym=tsb_app=0
[[noreturn]] void appjump()
{
settle();
tsb_app();
}
// Step g_addr one page down and erase that page. The decrement lives in here,
// before the erase's own use of it, not in the caller's loop where a following
// call would get it deleted (see header).
[[gnu::noinline, gnu::noclone]] void erase_below()
{
g_addr -= page;
spm::command<off>(spm::op::erase, g_addr);
settle();
}
// Erase the whole application, top-down like the oracle: the loop bound is a
// compare with zero, and g_addr = 0 - the value every caller wants next - is
// handed back for free.
[[gnu::noinline, gnu::noclone]] void erase_application()
{
g_addr = app_end;
do {
erase_below();
} while (g_addr != 0);
}
// Stream one host page into the erased flash page at g_addr (SPM word buffer,
// low byte then high) - no SRAM staging, receive and program are one loop.
// g_addr is left at the next page base.
[[gnu::noinline, gnu::noclone]] void store_flash()
{
const auto open = spm::page::begin<spm::from::boot_section, off>(g_addr);
g_cnt = page / 2;
do {
std::uint16_t word = rx();
word |= static_cast<std::uint16_t>(rx()) << 8;
spm::fill<off>(open, g_addr, word);
g_addr += 2;
} while (--g_cnt);
spm::command<off>(spm::op::write, g_addr - page);
settle();
}
[[noreturn, gnu::noinline]] void run()
{
// A watchdog reset hands straight back to the application, as the
// reference loader does, rather than re-entering the bootloader.
if (hw::mcusr::wdrf.test()) {
appjump();
}
// Lean bring-up from reset state: UCSR0C already reads 8N1, UBRR0H reads
// 0, and rx()/tx() raise RXEN0/TXEN0 on first use - only the divisor low
// byte and U2X0 need a store. The library still does the datasheet work.
static_assert(baud.u2x && baud.ubrr < 256, "lean bring-up writes UBRR0L only, with U2X0");
hw::ubrr0::write(static_cast<std::uint8_t>(baud.ubrr));
hw::ucsr0a::write(hw::ucsr0a::u2x0(1));
// General-purpose registers are undefined at power-on (no crt zeroes them);
// the direction latch must start "not receiving" so the first rx() enables
// the receiver. The reference loader clears its shadow register for the
// same reason.
g_receiving = 0;
// Activation: 3x'@', each inside the config page's timeout window (rx
// floors it so a corrupt page cannot lock the loader out); anything else -
// including silence - hands over.
g_window = avr::flash_load(flash_ptr(app_end + 2));
for (std::uint8_t k = 3; k; --k) {
if (rx() != knock) {
appjump();
}
}
g_window = comm_window;
// Password gate (config page from app_end+3, 0xff-terminated; a blank
// page is no password). A wrong byte blanks the comparison and drains the
// line forever, so a wrong password can never fall through; a 0 requests
// emergency erase behind two confirms. On pass the info block goes out;
// the emergency path skips it and drops into the command loop.
g_addr = app_end + 3;
std::uint8_t mask = 0xff;
for (;;) {
std::uint8_t expected = avr::flash_load(flash_ptr(g_addr)) & mask;
++g_addr;
if (expected == 0xff) {
g_addr = reinterpret_cast<std::uint16_t>(info.data());
g_cnt = sizeof(info);
sendf();
break;
}
std::uint8_t got = rx();
if (got == 0) {
if (mask == 0) {
continue;
}
if (rcnf() != confirm || rcnf() != confirm) {
appjump();
}
erase_application(); // leaves g_addr = 0 for the EEPROM walk
do {
eewr(0xff);
} while (g_addr <= eeprom_end);
g_addr = app_end + page;
erase_below();
break;
}
if (got != expected) {
mask = 0;
}
}
for (;;) {
tx(confirm); // Mainloop ready
g_addr = 0;
switch (rx()) {
case 'f': // read application flash, one page per host '!'
for (;;) {
if (rx() != confirm) {
break;
}
g_cnt = page;
sendf();
if (g_addr >= app_end) {
break;
}
}
break;
case 'F': // erase the application, then take pages behind '?'
erase_application(); // leaves g_addr = 0, the write start
while (rcnf() == confirm) {
store_flash();
}
break;
case 'e': // read EEPROM, one page per host '!', until the host stops
for (;;) {
if (rx() != confirm) {
break;
}
g_cnt = page;
do {
tx(eerd());
} while (--g_cnt);
}
break;
case 'E': // take EEPROM pages behind '?'
while (rcnf() == confirm) {
g_cnt = page;
do {
eewr(rx());
} while (--g_cnt);
}
break;
case 'c': // read the config page
read_config:
g_addr = app_end;
g_cnt = page;
sendf();
break;
case 'C': // replace the config page, then echo it back to verify
if (rcnf() != confirm) {
break;
}
g_addr = app_end + page;
erase_below(); // leaves g_addr = app_end, the store target
store_flash();
goto read_config;
default: // 'q' or any other byte runs the application
appjump();
}
}
}
} // namespace
} // namespace tsb
// Reset lands at the boot section base (BOOTRST): the entry stub in .vectors
// is laid first and does the one line of crt a crt-less image needs.
template struct avr::startup::entry<tsb::run, avr::startup::stack::hardware>;

1
tsb/type

Submodule tsb/type deleted from ce31ef017f

1
tsb/uart

Submodule tsb/uart deleted from ae03c8d43e