sl-firmware
ca23407ceb
- 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>
170 lines
6.2 KiB
C
170 lines
6.2 KiB
C
/*
|
||
* bmp280.c — BMP280/BME280 barometer driver (I2C1, shared bus)
|
||
*
|
||
* Probes 0x76 first, then 0x77. Requires i2c1_init() before bmp280_init().
|
||
* Returns chip_id on success (0x58=BMP280, 0x60=BME280), negative if absent.
|
||
*
|
||
* All HAL_I2C_Mem_Read/Write calls use 100ms timeouts — init cannot hang
|
||
* indefinitely even if the I2C bus is stuck or the breakout is absent.
|
||
*
|
||
* BME280 (chip_id 0x60): bmp280_read_humidity() returns %RH × 10.
|
||
* Call bmp280_read() first to refresh t_fine, then bmp280_read_humidity().
|
||
*/
|
||
#include "bmp280.h"
|
||
#include "i2c1.h"
|
||
#include <math.h>
|
||
|
||
static uint16_t s_addr;
|
||
static int s_chip_id; /* 0x58=BMP280, 0x60=BME280, 0=none */
|
||
|
||
/* Shared temp/pressure calibration */
|
||
static uint16_t dig_T1;
|
||
static int16_t dig_T2, dig_T3;
|
||
static uint16_t dig_P1;
|
||
static int16_t dig_P2, dig_P3, dig_P4, dig_P5, dig_P6, dig_P7, dig_P8, dig_P9;
|
||
static int32_t t_fine; /* updated by bmp280_read(); used by bmp280_read_humidity() */
|
||
|
||
/* BME280-only humidity calibration (chip_id 0x60) */
|
||
static uint8_t dig_H1;
|
||
static int16_t dig_H2;
|
||
static uint8_t dig_H3;
|
||
static int16_t dig_H4, dig_H5;
|
||
static int8_t dig_H6;
|
||
|
||
static uint8_t i2c_read(uint8_t reg) {
|
||
uint8_t val = 0;
|
||
HAL_I2C_Mem_Read(&hi2c1, s_addr, reg, 1, &val, 1, 100);
|
||
return val;
|
||
}
|
||
|
||
static void i2c_read_burst(uint8_t reg, uint8_t *buf, uint8_t len) {
|
||
HAL_I2C_Mem_Read(&hi2c1, s_addr, reg, 1, buf, len, 100);
|
||
}
|
||
|
||
static void i2c_write(uint8_t reg, uint8_t val) {
|
||
HAL_I2C_Mem_Write(&hi2c1, s_addr, reg, 1, &val, 1, 100);
|
||
}
|
||
|
||
static int try_init(uint16_t addr) {
|
||
s_addr = addr;
|
||
uint8_t id = i2c_read(0xD0);
|
||
if (id != 0x58 && id != 0x60) return -(int)id;
|
||
s_chip_id = (int)id;
|
||
|
||
/* Temp/pressure calibration (0x88–0x9D, identical layout on BMP280 and BME280) */
|
||
uint8_t cal[26];
|
||
i2c_read_burst(0x88, cal, 26);
|
||
dig_T1 = (uint16_t)(cal[1] << 8 | cal[0]);
|
||
dig_T2 = (int16_t) (cal[3] << 8 | cal[2]);
|
||
dig_T3 = (int16_t) (cal[5] << 8 | cal[4]);
|
||
dig_P1 = (uint16_t)(cal[7] << 8 | cal[6]);
|
||
dig_P2 = (int16_t) (cal[9] << 8 | cal[8]);
|
||
dig_P3 = (int16_t) (cal[11] << 8 | cal[10]);
|
||
dig_P4 = (int16_t) (cal[13] << 8 | cal[12]);
|
||
dig_P5 = (int16_t) (cal[15] << 8 | cal[14]);
|
||
dig_P6 = (int16_t) (cal[17] << 8 | cal[16]);
|
||
dig_P7 = (int16_t) (cal[19] << 8 | cal[18]);
|
||
dig_P8 = (int16_t) (cal[21] << 8 | cal[20]);
|
||
dig_P9 = (int16_t) (cal[23] << 8 | cal[22]);
|
||
|
||
if (id == 0x60) {
|
||
/* BME280: humidity calibration.
|
||
* dig_H1 : 0xA1 (uint8)
|
||
* dig_H2 : 0xE1–0xE2 (int16, LSB first)
|
||
* dig_H3 : 0xE3 (uint8)
|
||
* dig_H4 : 0xE4[7:0] | 0xE5[3:0] (int12)
|
||
* dig_H5 : 0xE5[7:4] | 0xE6[7:0] (int12)
|
||
* dig_H6 : 0xE7 (int8)
|
||
*/
|
||
dig_H1 = i2c_read(0xA1);
|
||
uint8_t hcal[7];
|
||
i2c_read_burst(0xE1, hcal, 7);
|
||
dig_H2 = (int16_t)((hcal[1] << 8) | hcal[0]);
|
||
dig_H3 = hcal[2];
|
||
dig_H4 = (int16_t)((hcal[3] << 4) | (hcal[4] & 0x0F));
|
||
dig_H5 = (int16_t)((hcal[5] << 4) | (hcal[4] >> 4));
|
||
dig_H6 = (int8_t)hcal[6];
|
||
|
||
/* ctrl_hum (0xF2) MUST be written before ctrl_meas (0xF4) — hardware req */
|
||
i2c_write(0xF2, 0x05); /* osrs_h = ×16 */
|
||
}
|
||
|
||
i2c_write(0xF5, 0x00); /* config: standby=0.5ms, filter=off */
|
||
i2c_write(0xF4, 0xB7); /* ctrl_meas: osrs_t=×16, osrs_p=×16, normal mode */
|
||
|
||
return (int)id;
|
||
}
|
||
|
||
int bmp280_init(void) {
|
||
int ret = try_init(0x76 << 1);
|
||
if (ret > 0) return ret;
|
||
return try_init(0x77 << 1);
|
||
}
|
||
|
||
void bmp280_read(int32_t *pressure_pa, int16_t *temp_x10) {
|
||
uint8_t buf[6];
|
||
i2c_read_burst(0xF7, buf, 6);
|
||
|
||
int32_t adc_P = (int32_t)((buf[0] << 12) | (buf[1] << 4) | (buf[2] >> 4));
|
||
int32_t adc_T = (int32_t)((buf[3] << 12) | (buf[4] << 4) | (buf[5] >> 4));
|
||
|
||
/* Temperature compensation (BME280/BMP280 datasheet Section 4.2.3) */
|
||
int32_t v1 = ((((adc_T >> 3) - ((int32_t)dig_T1 << 1))) * ((int32_t)dig_T2)) >> 11;
|
||
int32_t v2 = (((((adc_T >> 4) - (int32_t)dig_T1) *
|
||
((adc_T >> 4) - (int32_t)dig_T1)) >> 12) * (int32_t)dig_T3) >> 14;
|
||
t_fine = v1 + v2;
|
||
*temp_x10 = (int16_t)((t_fine * 5 + 128) >> 8); /* 0.1 °C */
|
||
|
||
/* Pressure compensation */
|
||
int64_t p1 = ((int64_t)t_fine) - 128000;
|
||
int64_t p2 = p1 * p1 * (int64_t)dig_P6;
|
||
p2 += (p1 * (int64_t)dig_P5) << 17;
|
||
p2 += ((int64_t)dig_P4) << 35;
|
||
p1 = ((p1 * p1 * (int64_t)dig_P3) >> 8) + ((p1 * (int64_t)dig_P2) << 12);
|
||
p1 = ((((int64_t)1 << 47) + p1)) * ((int64_t)dig_P1) >> 33;
|
||
if (p1 == 0) { *pressure_pa = 0; return; }
|
||
int64_t p = 1048576 - adc_P;
|
||
p = (((p << 31) - p2) * 3125) / p1;
|
||
p1 = ((int64_t)dig_P9 * (p >> 13) * (p >> 13)) >> 25;
|
||
p2 = ((int64_t)dig_P8 * p) >> 19;
|
||
*pressure_pa = (int32_t)(((p + p1 + p2) >> 8) + ((int64_t)dig_P7 << 4)) / 256;
|
||
}
|
||
|
||
/*
|
||
* BME280-only humidity readout. MUST be called after bmp280_read() (uses t_fine).
|
||
*
|
||
* Compensation: BME280 datasheet section 4.2.3 integer formula.
|
||
* Result is Q22.10 fixed-point: 1024 units = 1 %RH.
|
||
*
|
||
* Returns humidity in %RH × 10 (e.g. 500 = 50.0 %RH).
|
||
* Returns -1 if chip is BMP280 (no humidity sensor).
|
||
*/
|
||
int16_t bmp280_read_humidity(void) {
|
||
if (s_chip_id != 0x60) return -1;
|
||
|
||
uint8_t hbuf[2];
|
||
i2c_read_burst(0xFD, hbuf, 2);
|
||
int32_t adc_H = (int32_t)((hbuf[0] << 8) | hbuf[1]);
|
||
|
||
/* BME280 datasheet section 4.2.3 — floating-point compensation.
|
||
* Single-precision float is hardware-accelerated on STM32F7 (FPv5-SP FPU).
|
||
* Called at 50 Hz — negligible overhead.
|
||
*/
|
||
float var_H = ((float)t_fine) - 76800.0f;
|
||
var_H = (adc_H - (((float)dig_H4) * 64.0f + ((float)dig_H5) / 16384.0f * var_H)) *
|
||
(((float)dig_H2) / 65536.0f *
|
||
(1.0f + ((float)dig_H6) / 67108864.0f * var_H *
|
||
(1.0f + ((float)dig_H3) / 67108864.0f * var_H)));
|
||
var_H *= (1.0f - (float)dig_H1 * var_H / 524288.0f);
|
||
if (var_H > 100.0f) var_H = 100.0f;
|
||
if (var_H < 0.0f) var_H = 0.0f;
|
||
return (int16_t)(var_H * 10.0f + 0.5f); /* %RH × 10, rounded */
|
||
}
|
||
|
||
int32_t bmp280_pressure_to_alt_cm(int32_t pressure_pa) {
|
||
/* Barometric formula: h = 44330 * (1 - (p/p0)^(1/5.255)) metres */
|
||
float ratio = (float)pressure_pa / 101325.0f;
|
||
float alt_m = 44330.0f * (1.0f - powf(ratio, 0.1902949f));
|
||
return (int32_t)(alt_m * 100.0f); /* cm */
|
||
}
|