BlackMark
dc89d0779a
master opens in Studio, so this branch should too. The solution builds example/main.cpp — the port's only executable, the driver itself being an INTERFACE library — for the ATmega328P that solution targeted, and the acceptance is not that it builds but that it builds the same firmware: .text comes out byte-identical to CMake's at 1242 B. One project, one chip. Studio carries avrdevice as a project property, so the attiny85 half of the presets would need a second project rather than a second configuration; CMake stays the build system and covers both. libavr is found beside this repo, anchored to the project directory rather than written relative to the generated makefile, which runs from the configuration's output directory. No LIBAVR_ROOT: a variable exported in a shell is invisible to Studio launched from the Start menu. Both configurations verified headless with LIBAVR_ROOT unset, and the flag mirror checked against the CMake build's own compile_commands.json. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2.6 KiB
ds3231
Maxim DS3231 RTC driver on libavr:
clock and alarm read/write, alarm interrupts, oscillator-stop detection,
die temperature. One source runs on every libavr chip — TWI hardware on
the mega328P, open-drain software I2C on the tinies. All bus errors
surface as std::expected.
using bus = dev::i2c<{.frequency = 100_kHz}>;
using rtc = ds3231::device<bus>;
auto now = rtc::read_clock(); // result<date_time>
(void)rtc::set_alarm1({}, ds3231::alarm1_rate::once_per_second);
example/main.cpp is the full tour. Build with a libavr checkout:
LIBAVR_ROOT=/path/to/libavr cmake --preset attiny85-generated
cmake --build --preset attiny85-generated
Presets cover attiny85/atmega328p in both libavr modes (generated and
reflect). The legacy yazoalfa-based driver lives on the master branch.
Atmel Studio
master carries a Studio solution, so this branch does too: ide/ds3231.atsln
builds example/main.cpp for the ATmega328P — the chip that solution targeted —
to a byte-identical .text (1242 B) against the CMake build, with the flags
mirrored by hand. One project, one chip: avrdevice is a project-level property
in Studio, so the attiny85 half of the presets has no equivalent here, and CMake
remains the build system.
Studio expects libavr checked out beside this repo and finds it at
$(MSBuildProjectDirectory)\..\..\libavr\include — anchored to the project,
because a plain relative path is resolved 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. It also needs a GCC 16.1 toolchain registered as
flavour avr-g++-16.1.0, nothing older reaching -std=c++26.
One generated file is required before the project will load, and one command
checks the flags have not drifted (both from libavr's tools/atmelstudio/):
python ../libavr/tools/atmelstudio/componentinfo.py \
ide/ds3231.componentinfo.xml --device ATmega328P
python ../libavr/tools/atmelstudio/check-flags.py --solution ide/ds3231.atsln \
--compile-commands build/atmega328p-generated/compile_commands.json \
--log build/atmelstudio.log
Release is what the gate compares, the presets defining no debug build; Debug
carries the -Og -gdwarf-4 pair libavr's own debug preset uses.
Differences from legacy: weekday-rate alarms now actually set the DY bit
(the old setAlarmHelper always cleared it), reads/writes are single
coherent bus transactions, and errors are reported instead of ignored.