sl-mechanical
c96ed54af2
ADC-based coulomb integration for SaltyBot battery state-of-charge (SOC) tracking: **Core Features**: - INA219 I2C current sensor integration (10mΩ shunt, ±3.2A range) - Coulomb integration at 1kHz tick rate (Q = ∫I dt) - SOC calculation: 100% × (1 - Discharged_Q / Capacity_Q) - Runtime state tracking: current, coulombs, SOC, tick count, charging flag - Cycle tracking with depth-of-discharge (DOD) calculation - Flash-persistent calibration (offset/scale) with magic checksum (0xCAFEBABE) **API Functions**: - coulomb_init() - Initialize INA219, load calibration - coulomb_tick() - 1kHz integration (current → coulombs → SOC) - coulomb_set_soc() / coulomb_mark_full_charge() - Manual calibration points - coulomb_mark_fully_discharged() - Cycle tracking - coulomb_save/load_calibration() - Flash persistence - coulomb_factory_reset() - Clear all state and calibration **Test Coverage** (19 test suites, 49 assertions): - Initialization and state reset - coulomb_tick() integration accuracy (zero current, constant discharge) - SOC calculation accuracy and clamping (0–100%) - Charging vs. discharging detection - Flash read/write with magic validation - Calibration offset/scale application - Cycle counting and DOD tracking - Long-duration integration (10s at 0.5A = 5 coulombs) - Boundary conditions and rollover handling - Capacity variants (2200–3000 mAh) **Data Structures**: - coulomb_state_t: Runtime state (volatile) - coulomb_calibration_t: Flash storage (persistent) - coulomb_cycle_t: Cycle history with DOD tracking **Integration Details**: - Battery capacity: 2200 mAh (611 coulombs) — configurable per variant - Flash address: 0x0800D000 (1 sector, STM32F4) - Sampling: 1kHz systick, 1ms per integration window - Discharge threshold: 50mA (filtering noise) All tests pass (49/49 assertions); ready for hardware integration. Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>