`set_alarm1/2`'s `enable_interrupt = false` did nothing at all - it skipped the
control-register write rather than clearing A1IE/A2IE - and there was no other
way to clear them, so an alarm armed once with its interrupt on drove INT/SQW
for good. It is `alarm_interrupt::off` now and it clears the bit, with
`listen_alarm1/2()` and `mute_alarm1/2()` beside it for a caller that arms once
and changes its mind later. The bare bool went with it (rule 37): `set_alarm1(at,
rate, false)` said nothing at the point of use.
`bool SetWeekday` was the same shape one level up - `device<bus, false>` names
nothing - and its two writers disagreed about what it meant: `write_date`
skipped the weekday register, `write_clock` stamped a placeholder 1 into it, so
a program that turned the maintenance off still had the register overwritten
and no way to set it. `weekday_source::external` now means the register is the
program's, in both writers.
test/consteval.cpp is the battery this driver never had, over the arithmetic
that has no bus in it: the BCD round trip across every representable value and
its nibble layout, the hours register in both formats including all four
noon/midnight cases, Sakamoto's weekday against six calendar dates (leap day,
the day after it, and 2100's missing leap), and both alarms' rate encodings
transcribed against 19-5170 Table 2 - including that alarm 2's masks sit one
place below alarm 1's, which is the property that makes one distribution loop
wrong for the other. Red-green: two assertions fire on a flipped DY bit.
Beside it, one decode rather than two: `read_clock` and `read_time` spelled the
seconds/minutes/hours triplet out separately (rule 6).
Every image byte-identical on both chips in both modes.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The register sugar now rides the bus's own master role - device<Bus>
resolves avr::i2c::device<typename Bus::master, bus_address>, so a
consumer keeps handing over its declared dev::i2c<...> unchanged - and
the DS3231's hardwired 0x68 is a named constant. The example's four
discards became the LED's own error signal (a failed seed or a failed
alarm clear holds it dark, the same word a stuck bus says), the tree is
reformatted under InsertBraces, the sources are ASCII, and the README's
stale Studio byte counts are replaced by the claim its check-flags gate
holds.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The submodule replaces FetchContent and the unpinned forge fallback;
LIBAVR_ROOT stays as the tandem-development override, the presets take the
toolchain file from the submodule, and the Studio project's include path
anchors there — correct by construction.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Same driver surface as the yazoalfa version — clock and alarm get/set,
alarm interrupts, flag check/clear — plus oscillator-stop detection and
die temperature. One source for tiny85 (software I2C) and mega328P (TWI),
built against libavr in both generated and reflect mode, byte-identical
.text across modes. Errors surface as std::expected instead of being
dropped; weekday-rate alarms now really set the DY bit (legacy cleared
it); multi-register access is one coherent bus transaction. Legacy stays
on master.
Co-Authored-By: Claude <noreply@anthropic.com>
