docs: comments state what is, not how it came to be

The loader build, the gate script and the line-ending rule each carried the
story of their arrival - a measurement off the bench, a loop got wrong by
hand, a checkout reached from two hosts - where a sentence of what holds now
is enough. .gitattributes loses two patterns for files this repository does
not have, .clangd its two non-ASCII dashes, two headers a "per C" that read
as a stripped degree sign, and the README a "(new)" and the port's own
first attempt at stopping monitor.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.clangd

@@ -5,7 +5,7 @@ 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.
+    # 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
@@ -14,7 +14,7 @@ CompileFlags:
     - -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
+    # 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:

.gitattributes

@@ -1,12 +1,7 @@
-# Line endings are the repository's, not the editing machine's: this checkout
+# Line endings are the repository's, not the editing tool's: a file rewritten
-# is reached from two hosts, and a file rewritten by a Windows tool comes back
+# by a Windows tool must not come back with every line changed.
-# 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
 *.atsln     eol=crlf

CMakeLists.txt

@@ -37,14 +37,12 @@ add_custom_command(TARGET fantemp POST_BUILD
                    COMMAND ${CMAKE_OBJCOPY} -O ihex -R .eeprom
                            $<TARGET_FILE:fantemp> $<TARGET_FILE_DIR:fantemp>/fantemp.hex)
 
-# The board's loader, built here rather than named from memory: consuming
+# The board's loader, built from the pin, so the one image this deployment
-# pureboot for its geometry alone left the one image this deployment cannot be
+# cannot be recovered without is rebuilt by the commit that names it. Every
-# recovered without outside the repository that pins it. Every parameter is
+# parameter is pureboot's own default for this chip - USART0 at 115200 on the
-# pureboot's own default for this chip - USART0 at 115200 on the 16 MHz crystal
+# 16 MHz crystal `src/board.hpp` declares. It goes on over the wire
-# `src/board.hpp` declares - and that is measured rather than assumed, the
+# (`--update-loader`), which is why there is no flash target beside it: the
-# image being byte-for-byte the 386 B the board's slot reads back. It goes on
+# board has no programming header.
-# over the wire (`--update-loader`), which is why there is no flash target
-# beside it: no programmer has ever been in this board's path.
 pureboot_add_loader(pureboot)
 
 enable_testing()

README.md

@@ -18,7 +18,7 @@ Commands may be abbreviated to any unambiguous-by-order prefix, as the legacy
 firmware allowed: `up` is `uptime`, `st` is `statistics`, `sa` is `save`. The
 table order resolves ties, so `s` is `show` — and `reset` is deliberately the one
 command that cannot be abbreviated, because `r` should not be able to wipe the
-histogram. `save` (new) forces a writeback, which otherwise happens every 30
+histogram. `save` forces a writeback, which otherwise happens every 30
 minutes and on the way into the bootloader.
 
 `show`, `statistics` and the histogram print one value per line behind a dotted
@@ -28,9 +28,8 @@ from 10 to 60 with a bar, because the curve is a cubic and five-degree samples
 without a graph show none of its shape.
 
 **Ctrl+C** abandons a half-typed line and gives a fresh prompt, echoing `^C`, and
-it is what stops `monitor`. Stopping on *any* byte, which is what the port did
+it is what stops `monitor`. Stopping on *any* byte would not do: a host's line
-first, reads well right up until a host sends a line ending: `monitor\r\n` then
+ending would stop `monitor\r\n` on the `\n` it arrived with, one reading in.
-stopped itself on the `\n` it arrived with, one reading in.
 
 ## Reaching the bootloader
 

src/curve.hpp

@@ -6,7 +6,7 @@
 #include <libavr/flash.hpp>
 
 // The auto-mode fan curve, tabulated at compile time as a flash_table of duty
-// percent per C: a cubic that is held at zero below the temperature the fan
+// percent per degree C: a cubic that is held at zero below the temperature the fan
 // starts at.
 namespace app::curve {
 

src/statistics.hpp

@@ -7,7 +7,7 @@
 
 #include "board.hpp"
 
-// Temperature histogram: one uint32 bucket per C 0..99, sampled once a
+// Temperature histogram: one uint32 bucket per degree C 0..99, sampled once a
 // second, written back to EEPROM every 30 minutes (update() only touches
 // changed bytes).
 namespace app {

tools/check.sh

@@ -1,11 +1,10 @@
 #!/usr/bin/env bash
 # The task gate: every configure preset built, and only then every one tested.
 #
-# The loop itself is libavr's (tools/check-presets.sh) because the order in it
+# The loop is libavr's (tools/check-presets.sh): the mode-identity checks read
-# is subtle and was got wrong by hand more than once - the mode-identity checks
+# the sibling mode's tree, so a build-then-test-per-preset run would compare a
-# read the sibling mode's tree, so a build-then-test-per-preset run compares a
 # fresh image against a stale sibling. Anything this repository needs beyond
-# the presets is written after the call, where every tree is built and tested.
+# the presets goes after the call, where every tree is built and tested.
 set -euo pipefail
 cd "$(dirname "${BASH_SOURCE[0]}")/.."
 "${LIBAVR_ROOT:-libavr}/tools/check-presets.sh" "$@"