sl-perception 410ace3540 feat: battery coulomb counter (Issue #325)
Add coulomb counter for accurate SoC estimation independent of load:

- New coulomb_counter module: integrate current over time to track Ah consumed
  * coulomb_counter_init(capacity_mah) initializes with battery capacity
  * coulomb_counter_accumulate(current_ma) integrates current at 100 Hz
  * coulomb_counter_get_soc_pct() returns SoC 0-100% (255 = invalid)
  * coulomb_counter_reset() for charge-complete reset

- Battery module integration:
  * battery_accumulate_coulombs() reads motor INA219 currents and accumulates
  * battery_get_soc_coulomb() returns coulomb-based SoC with fallback to voltage
  * Initialize coulomb counter at startup with DEFAULT_BATTERY_CAPACITY_MAH

- Telemetry updates:
  * JLink STATUS: use coulomb SoC if available, fallback to voltage-based
  * CRSF battery frame: now includes remaining capacity in mAh (from coulomb counter)
  * CRSF capacity field was always 0; now reflects actual remaining mAh

- Mainloop integration:
  * Call battery_accumulate_coulombs() every tick for continuous integration
  * INA219 motor currents + 200 mA subsystem baseline = total battery draw

Motor current sources (INA219 addresses 0x40/0x41) provide most power draw;
Jetson ROS2 battery_node already prioritizes coulomb-based soc_pct from STATUS frame.

Default capacity: 2200 mAh (typical lab 3S LiPo); configurable via firmware parameter.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
2026-03-03 17:35:34 -05:00

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#ifndef BATTERY_H
#define BATTERY_H
/*
* battery.h — Vbat ADC reading for CRSF telemetry (Issue #103)
*
* Hardware: ADC3 channel IN11 on PC1 (ADC_BATT 1, Mamba F722).
* Voltage divider: 10 kΩ / 1 kΩ → 11:1 ratio.
* Resolution: 12-bit (04095), Vref = 3.3 V.
*
* Filtered output in millivolts. Reading is averaged over
* BATTERY_SAMPLES conversions (software oversampling) to reduce noise.
*/
#include <stdint.h>
/* Initialise ADC3 for single-channel Vbat reading on PC1. */
void battery_init(void);
/*
* battery_read_mv() — blocking single-shot read; returns Vbat in mV.
* Takes ~1 µs (12-bit conversion at 36 MHz APB2 / 8 prescaler = 4.5 MHz ADC clk).
* Returns 0 if ADC not initialised or conversion times out.
*/
uint32_t battery_read_mv(void);
/*
* battery_estimate_pct() — coarse SoC estimate from Vbat (mV).
* Works for 3S LiPo (10.512.6 V) and 4S (14.016.8 V).
* Detection is automatic based on voltage.
* Returns 0100, or 255 if voltage is out of range.
*/
uint8_t battery_estimate_pct(uint32_t voltage_mv);
/*
* battery_accumulate_coulombs() — periodically integrate battery current.
* Call every 10-20 ms (50-100 Hz) from main loop to accumulate coulombs.
* Reads motor currents from INA219 sensors.
*/
void battery_accumulate_coulombs(void);
/*
* battery_get_soc_coulomb() — get coulomb-based SoC estimate.
* Returns 0100 (percent), or 255 if coulomb counter not yet valid.
* Preferred over voltage-based when valid.
*/
uint8_t battery_get_soc_coulomb(void);
#endif /* BATTERY_H */