- bmp280.c: detect BME280 (chip_id 0x60) vs BMP280 (0x58) at init
- bmp280.c: read humidity calibration (dig_H1–H6) from 0xA1 and 0xE1–0xE7
- bmp280.c: set ctrl_hum (0xF2, osrs_h=×16) before ctrl_meas — hardware req
- bmp280.c: add bmp280_read_humidity() — float compensation (FPv5-SP FPU),
returns %RH × 10; -1 if chip is BMP280 or not initialised
- bmp280.h: add bmp280_read_humidity() declaration + timeout note
- main.c: baro_ok → baro_chip (stores chip_id for BME280 detection)
- main.c: telemetry adds t (°C×10), pa (hPa×10) for all barometers;
adds h (%RH×10) for BME280 only; alt unchanged
- ui/index.html: hidden TEMP/HUMIDITY/PRESSURE rows, revealed on first
packet containing t/h/pa fields; values shown with 1 dp
I2C hang safety: all HAL_I2C_Mem_Read/Write use 100ms timeouts, so
missing hardware (NAK) returns in <1ms, not after a hang.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Shared I2C1 bus (i2c1.c/h, PB8=SCL PB9=SDA 100kHz):
- i2c1_init() called once in main() before sensor probes.
- hi2c1 exported globally; baro and mag drivers use it directly.
Barometer (bmp280.c):
- Probes I2C1 at 0x76 then 0x77 (covers both SDO options).
- bmp280_init() returns chip_id (0x58/0x60) on success, neg if absent.
- Added bmp280_pressure_to_alt_cm() — ISA barometric formula.
- Added bmp280.h (was missing).
Magnetometer (mag.c / mag.h):
- Auto-detects QMC5883L (0x0D, id=0xFF), HMC5883L (0x1E, id='H43'),
IST8310 (0x0E, id=0x10) in that order.
- mag_read_heading() returns degrees×10 (0–3599) or -1 if not ready.
- HMC5883L: correct XZY byte order applied.
- IST8310: single-measurement trigger mode.
main.c:
- i2c1_init() + bmp280_init() + mag_init() after all other inits.
- Both skip gracefully (baro_ok=0, mag_type=MAG_NONE) if not present.
- Telemetry JSON: incremental builder appends ",\"hd\":<n>" when mag
found and ",\"alt\":<n>" when baro found. No extra bytes when absent.
UI (index.html):
- HEADING and ALT rows hidden until first packet with that field.
- Heading shown in degrees, alt in metres (firmware sends cm).
Closes#24.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
