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Improved pressure computation function by reading the pressure and temperature registers in one shot

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This commit is contained in:
Anatole SCHRAMM 2024-01-11 13:41:43 +01:00
parent 2098121ae0
commit e47498b8bd
1 changed files with 33 additions and 23 deletions
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54
src/W800_SDK_v1.00.10/app/app_drivers/i2c/BMP280.c
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@ -117,6 +117,28 @@ static bool _BMP280_read_calibration_data(void)
return true; return true;
} }
static float _BMP280_compute_temperature(uint8_t *data)
{
int32_t var1, var2;
int32_t adc_T = data[0] << 16 | data[1] << 8 | data[2];
adc_T >>= 4;
var1 = ((((adc_T >> 3) - ((int32_t)_calibration_data.dig_T1 << 1))) *
((int32_t)_calibration_data.dig_T2)) >>
11;
var2 = (((((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1)) *
((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1))) >>
12) *
((int32_t)_calibration_data.dig_T3)) >>
14;
t_fine = var1 + var2;
float T = (t_fine * 5 + 128) >> 8;
return T / 100.0;
}
bool BMP280_init(void) bool BMP280_init(void)
{ {
uint8_t data; uint8_t data;
@ -162,40 +184,28 @@ bool BMP280_is_measuring(void)
float BMP280_get_temperature(void) float BMP280_get_temperature(void)
{ {
int32_t var1, var2;
uint8_t data[3]; uint8_t data[3];
if(!i2c_read(BMP280_I2C_ADDR, BMP280_TEMP_MSB, data, sizeof data)) return 0.0f; if(!i2c_read(BMP280_I2C_ADDR, BMP280_TEMP_MSB, data, sizeof data)) return 0.0f;
int32_t adc_T = data[0] << 16 | data[1] << 8 | data[2]; return _BMP280_compute_temperature(data);
adc_T >>= 4;
var1 = ((((adc_T >> 3) - ((int32_t)_calibration_data.dig_T1 << 1))) *
((int32_t)_calibration_data.dig_T2)) >>
11;
var2 = (((((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1)) *
((adc_T >> 4) - ((int32_t)_calibration_data.dig_T1))) >>
12) *
((int32_t)_calibration_data.dig_T3)) >>
14;
t_fine = var1 + var2;
float T = (t_fine * 5 + 128) >> 8;
return T / 100;
} }
float BMP280_get_pressure(float * const temperature) float BMP280_get_pressure(float * const temperature)
{ {
int64_t var1, var2, p; int64_t var1, var2, p;
uint8_t data[3]; uint8_t data[6];
float temp = BMP280_get_temperature(); /* When reading the pressure, we also need to get the associated temperature, so let's read everything at once */
if(!i2c_read(BMP280_I2C_ADDR, BMP280_PRESS_MSB, data, sizeof data))
{
if(temperature) *temperature = 0.0f;
return 0.0f;
}
float temp = _BMP280_compute_temperature(&data[3]);
if(temperature) *temperature = temp; if(temperature) *temperature = temp;
if(!i2c_read(BMP280_I2C_ADDR, BMP280_PRESS_MSB, data, sizeof data)) return 0.0f;
int32_t adc_P = data[0] << 16 | data[1] << 8 | data[2]; int32_t adc_P = data[0] << 16 | data[1] << 8 | data[2];
adc_P >>= 4; adc_P >>= 4;