diff options
Diffstat (limited to 'lib/bmp280.c')
| -rw-r--r-- | lib/bmp280.c | 160 |
1 files changed, 91 insertions, 69 deletions
diff --git a/lib/bmp280.c b/lib/bmp280.c index 89cf4cf..0519cca 100644 --- a/lib/bmp280.c +++ b/lib/bmp280.c @@ -26,9 +26,6 @@ #include <LUFA/Drivers/Peripheral/SPI.h> #include "bmp280.h" - -int32_t bmp280_t_fine = 0; - void bmp280_cs(bmp280_sensor *sensor, uint8_t select) { if (!select) @@ -37,115 +34,134 @@ void bmp280_cs(bmp280_sensor *sensor, uint8_t select) *(sensor->cs_port) &= ~ _BV(sensor->cs_pin); } -void bmp280_write8(uint8_t reg, uint8_t value) +void bmp280_write8(bmp280_sensor *sensor, uint8_t reg, uint8_t value) { + bmp280_cs(sensor, true); SPI_SendByte(reg & ~0x80); //bit 7 needs to be low for write mode SPI_SendByte(value); + bmp280_cs(sensor, false); } -uint8_t bmp280_read8(uint8_t reg) +uint8_t bmp280_read8(bmp280_sensor *sensor, uint8_t reg) { + bmp280_cs(sensor, true); SPI_SendByte(reg | 0x80); //bit 7 high for read mode - return SPI_ReceiveByte(); + uint8_t value = SPI_ReceiveByte(); + bmp280_cs(sensor, false); + return value; } -uint16_t bmp280_read16(uint8_t reg) +uint16_t bmp280_read16(bmp280_sensor *sensor, uint8_t reg) { uint16_t value = 0; - SPI_SendByte(reg | 0x80); //bit 7 high for read mode - value |= ((uint16_t) SPI_ReceiveByte() & 0xFF) << 8; - value |= (uint16_t) SPI_ReceiveByte() & 0xFF; - return value; + bmp280_cs(sensor, true); + SPI_SendByte(reg | 0x80); //bit 7 high for read mode + value |= ((uint16_t) SPI_ReceiveByte() & 0xFF) << 8; + value |= (uint16_t) SPI_ReceiveByte() & 0xFF; + bmp280_cs(sensor, false); + return value; } -uint32_t bmp280_read24(uint8_t reg) +uint32_t bmp280_read24(bmp280_sensor *sensor, uint8_t reg) { - uint32_t value = 0; - SPI_SendByte(reg | 0x80); //bit 7 high for read mode - value |= ((uint32_t) SPI_ReceiveByte() & 0xFF) << 16; - value |= ((uint32_t) SPI_ReceiveByte() & 0xFF) << 8; - value |= (uint32_t) SPI_ReceiveByte() & 0xFF; - return value; + uint32_t value = 0; + bmp280_cs(sensor, true); + SPI_SendByte(reg | 0x80); //bit 7 high for read mode + value |= ((uint32_t) SPI_ReceiveByte() & 0xFF) << 16; + value |= ((uint32_t) SPI_ReceiveByte() & 0xFF) << 8; + value |= (uint32_t) SPI_ReceiveByte() & 0xFF; + bmp280_cs(sensor, false); + return value; } -int16_t bmp280_readS16(uint8_t reg) +int16_t bmp280_readS16(bmp280_sensor *sensor, uint8_t reg) { - return (int16_t) bmp280_read16(reg); + return (int16_t) bmp280_read16(sensor, reg); } -uint16_t bmp280_read16_LE(uint8_t reg) +uint16_t bmp280_read16_LE(bmp280_sensor *sensor, uint8_t reg) { - uint16_t value = 0; - SPI_SendByte(reg | 0x80); //bit 7 high for read mode - value |= (uint16_t) SPI_ReceiveByte() & 0xFF; - value |= ((uint16_t) SPI_ReceiveByte() & 0xFF) << 8; - return value; + uint16_t value = bmp280_read16(sensor, reg); + return (value >> 8) | (value << 8); } -int16_t bmp280_readS16_LE(uint8_t reg) +int16_t bmp280_readS16_LE(bmp280_sensor *sensor, uint8_t reg) { - return (int16_t)bmp280_read16_LE(reg); + return (int16_t)bmp280_read16_LE(sensor, reg); } void bmp280_readCoefficients(bmp280_sensor *sensor) { - bmp280_cs(sensor, true); - sensor->dig_T1 = bmp280_read16_LE(BMP280_REGISTER_DIG_T1); - sensor->dig_T2 = bmp280_readS16_LE(BMP280_REGISTER_DIG_T2); - sensor->dig_T3 = bmp280_readS16_LE(BMP280_REGISTER_DIG_T3); - sensor->dig_P1 = bmp280_read16_LE(BMP280_REGISTER_DIG_P1); - sensor->dig_P2 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P2); - sensor->dig_P3 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P3); - sensor->dig_P4 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P4); - sensor->dig_P5 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P5); - sensor->dig_P6 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P6); - sensor->dig_P7 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P7); - sensor->dig_P8 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P8); - sensor->dig_P9 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P9); - bmp280_cs(sensor, false); + sensor->dig_T1 = bmp280_read16_LE(sensor,BMP280_REGISTER_DIG_T1); + sensor->dig_T2 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_T2); + sensor->dig_T3 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_T3); + sensor->dig_P1 = bmp280_read16_LE(sensor,BMP280_REGISTER_DIG_P1); + sensor->dig_P2 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P2); + sensor->dig_P3 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P3); + sensor->dig_P4 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P4); + sensor->dig_P5 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P5); + sensor->dig_P6 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P6); + sensor->dig_P7 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P7); + sensor->dig_P8 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P8); + sensor->dig_P9 = bmp280_readS16_LE(sensor,BMP280_REGISTER_DIG_P9); +} + +uint8_t bmp280_check_chipid(bmp280_sensor *sensor) +{ + uint8_t chip_id = bmp280_read8(sensor, BMP280_REGISTER_CHIPID); + return chip_id == 0x58; } //need to init SPI beforehand -void bmp280_init(bmp280_sensor *sensor, volatile uint8_t *cs_port, uint8_t cs_pin) +uint8_t bmp280_init(bmp280_sensor *sensor, volatile uint8_t *cs_port, uint8_t cs_pin) { memset(sensor,0,sizeof(bmp280_sensor)); sensor->cs_port = cs_port; sensor->cs_pin = cs_pin; + uint8_t sensor_available = bmp280_check_chipid(sensor); + if (!sensor_available) + return sensor_available; //don't talk with chip, it doesn't speak our language bmp280_readCoefficients(sensor); + bmp280_write8(sensor, BMP280_REGISTER_CONTROL, 0x3F); + return sensor_available; } -float bmp280_readTemp(bmp280_sensor *sensor) +int32_t bmp280_readFineTemp(bmp280_sensor *sensor) { int32_t var1, var2; - bmp280_cs(sensor, true); - int32_t adc_T = bmp280_read24(BMP280_REGISTER_TEMPDATA); - bmp280_cs(sensor, false); + int32_t adc_T = bmp280_read24(sensor, BMP280_REGISTER_TEMPDATA); adc_T >>= 4; - var1 = ((((adc_T>>3) - ((int32_t)sensor->dig_T1 <<1))) * - ((int32_t)sensor->dig_T2)) >> 11; + var1 = ((((adc_T>>3) - ((int32_t)sensor->dig_T1 <<1))) * ((int32_t)sensor->dig_T2)) >> 11; + var2 = (((((adc_T>>4) - ((int32_t)sensor->dig_T1)) * ((adc_T>>4) - ((int32_t)sensor->dig_T1))) >> 12) * ((int32_t)sensor->dig_T3)) >> 14; - var2 = (((((adc_T>>4) - ((int32_t)sensor->dig_T1)) * - ((adc_T>>4) - ((int32_t)sensor->dig_T1))) >> 12) * - ((int32_t)sensor->dig_T3)) >> 14; - - bmp280_t_fine = var1 + var2; + return var1 + var2; +} +float bmp280_convertTempToCelsius(int32_t bmp280_t_fine) +{ float T = (bmp280_t_fine * 5 + 128) >> 8; return T/100; } -float bmp280_readPressure(bmp280_sensor *sensor) +float bmp280_readTemp(bmp280_sensor *sensor) { + return bmp280_convertTempToCelsius(bmp280_readFineTemp(sensor)); +} + +bmp280_result bmp280_readTempAndPressure(bmp280_sensor *sensor) +{ + bmp280_result result; + result.temperature = 0; + result.pressure = 0; + int64_t var1, var2, p; - // Must be done first to get the bmp280_t_fine variable - bmp280_readTemp(sensor); + int32_t bmp280_t_fine = bmp280_readFineTemp(sensor); + result.temperature = bmp280_convertTempToCelsius(bmp280_t_fine); - bmp280_cs(sensor, true); - int32_t adc_P = bmp280_read24(BMP280_REGISTER_PRESSUREDATA); - bmp280_cs(sensor, false); + int32_t adc_P = bmp280_read24(sensor, BMP280_REGISTER_PRESSUREDATA); adc_P >>= 4; var1 = ((int64_t)bmp280_t_fine) - 128000; @@ -158,7 +174,7 @@ float bmp280_readPressure(bmp280_sensor *sensor) if (var1 == 0) { - return 0; // avoid exception caused by division by zero + return result; // avoid exception caused by division by zero } p = 1048576 - adc_P; p = (((p<<31) - var2)*3125) / var1; @@ -166,20 +182,26 @@ float bmp280_readPressure(bmp280_sensor *sensor) var2 = (((int64_t)sensor->dig_P8) * p) >> 19; p = ((p + var1 + var2) >> 8) + (((int64_t)sensor->dig_P7)<<4); - return (float)p/256; + result.pressure = (float)p/256; + return result; } -/*float bmp280_readAltitude(bmp280_sensor *sensor, float sealevelp) +float bmp280_readPressure(bmp280_sensor *sensor) { - float altitude; + bmp280_result result = bmp280_readTempAndPressure(sensor); + return result.pressure; +} - float pressure = bmp280_readPressure(sensor); // in Si units for Pascal +float bmp280_calcAltitude(float pressure, float sealevelp) +{ pressure /= 100; + return 44330 * (1.0 - pow(pressure / sealevelp, 0.1903)); +} - altitude = 44330 * (1.0 - pow(pressure / seaLevelhPa, 0.1903)); - - return altitude; -}*/ +float bmp280_readAltitude(bmp280_sensor *sensor, float sealevelp) +{ + return bmp280_calcAltitude(bmp280_readTempAndPressure(sensor).pressure, sealevelp); +} /// Helper Functions |