All notable changes to AcroClock will be documented in this file.
The format is based on Keep a Changelog. AcroClock uses Semantic Versioning.
requirements.md— initial requirements specification (REQ-001..013) and a task backlog across 10 phases. Draft v0.1.0.HISTORY.md— project milestone log; inception entry with component, architecture, and open-hardware decisions.CHANGELOG.md— this file.
- Project name: AcroClock (working title).
- Target MCU: STM32F103C8T6 on the existing AcroSched 2.2.0 (F103) port.
- Display: four single-digit common-cathode green seven-segment indicators (E11801-J-UG4-8-W), driven via a 74HC595 SPI chain + high-side source driver; colon from two discrete LEDs, blinking at 1 Hz; leading-zero blanking on the hours tens digit.
- Segment supply: bench-measured Vf ≈ 6 V @20 mA (3 dies in series) → ~6.5–7 V segment rail (5 V too low, 12 V not needed); full static draw ≈ 0.76 A.
- Sensors / peripherals: DS3231SN (time + temperature), BH1750FVI (ambient light), 24C01A EEPROM (settings with per-record CRC), BMT-1203UX buzzer.
- Input: rotary encoder via hardware timer + two buttons (Mode, Set/Enter).
- Four firmware-managed alarms with per-alarm LED indication and a 7-bit weekday mask (default daily).
- Segment rail voltage — depends on the 3-die internal wiring (series vs. parallel); datasheet table is per-chip only.
- Display drive: static vs. dynamic (multiplex) — affects driver topology and average current.
- Buzzer snooze / auto-stop timings.
- Whole-device 18650 backup (deferred, depends on the drive scheme).