Diff: bme280.h

Revision:

2:4700f7e71737

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/bme280.h	Sat Nov 30 04:49:09 2019 +0000
@@ -0,0 +1,216 @@
+/*
+  bme280.h - driver for Bosch Sensortec BME280 combined humidity and pressure sensor.
+ 
+  Copyright (c) 2015 Elektor
+ 
+  26/11/2015 - CPV, Initial release.
+  
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+ 
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General
+  Public License along with this library; if not, write to the
+  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+  Boston, MA  02111-1307  USA
+ 
+*/
+ 
+#ifndef __BME280_H__
+#define __BME280_H__
+ 
+#include <stdint.h>
+ 
+ 
+#define BME280_ALLOW_FLOAT  (1)
+ 
+#if BME280_ALLOW_FLOAT!=0
+  typedef double temperature_t;
+  typedef double pressure_t;
+  typedef double humidity_t;
+#else
+  typedef int32_t temperature_t;
+  typedef uint32_t pressure_t;
+  typedef uint32_t humidity_t;
+#endif /* BME280_ALLOW_FLOAT */
+ 
+ 
+// Two possible addresses, depending on level on SDO pin.
+#define BME280_I2C_ADDRESS1  (0x76)
+#define BME280_I2C_ADDRESS2  (0x77)
+ 
+// Calibration registers.
+#define BME280_CAL_T1  (0x88)
+#define BME280_CAL_T2  (0x8a)
+#define BME280_CAL_T3  (0x8c)
+#define BME280_CAL_P1  (0x8e)
+#define BME280_CAL_P2  (0x90)
+#define BME280_CAL_P3  (0x92)
+#define BME280_CAL_P4  (0x94)
+#define BME280_CAL_P5  (0x96)
+#define BME280_CAL_P6  (0x98)
+#define BME280_CAL_P7  (0x9a)
+#define BME280_CAL_P8  (0x9c)
+#define BME280_CAL_P9  (0x9e)
+#define BME280_CAL_H1  (0xa1) /* 8 bits */
+#define BME280_CAL_H2  (0xe1)
+#define BME280_CAL_H3  (0xe3) /* 8 bits */
+#define BME280_CAL_H4  (0xe4) /* 12 bits, combined with H45 */
+#define BME280_CAL_H45  (0xe5) /* 12 bits, combined with H5 */
+#define BME280_CAL_H5  (0xe6) /* 8 bits */
+#define BME280_CAL_H6  (0xe7) /* 8 bits */
+ 
+// Control registers.
+#define BME280_ID_REGISTER  (0xd0) /* 8 bits */
+#define BME280_RESET_REGISTER  (0xe0) /* 8 bits */
+#define BME280_CTRL_HUM_REGISTER  (0xf2) /* 8 bits */
+#define BME280_STATUS_REGISTER  (0xf3) /* 8 bits */
+#define BME280_CTRL_MEAS_REGISTER  (0xf4) /* 8 bits */
+#define BME280_CONFIG_REGISTER  (0xf5) /* 8 bits */
+ 
+// Measurement registers.
+#define BME280_PRESSURE  (0xf7) /* 20 bits */
+#define BME280_PRESSURE_MSB  (0xf7) /* 8 bits */
+#define BME280_PRESSURE_LSB  (0xf8) /* 8 bits */
+#define BME280_PRESSURE_XLSB  (0xf9) /* 8 bits */
+#define BME280_TEMPERATURE  (0xfa) /* 20 bits */
+#define BME280_TEMPERATURE_MSB  (0xfa) /* 8 bits */
+#define BME280_TEMPERATURE_LSB  (0xfb) /* 8 bits */
+#define BME280_TEMPERATURE_XLSB  (0xfc) /* 8 bits */
+#define BME280_HUMIDITY  (0xfd) /* 16 bits */
+#define BME280_HUMIDITY_MSB  (0xfd) /* 8 bits */
+#define BME280_HUMIDITY_LSB  (0xfe) /* 8 bits */
+ 
+// It is recommended to read all the measurements in one go.
+#define BME280_MEASUREMENT_REGISTER  (BME280_PRESSURE)
+#define BME280_MEASUREMENT_SIZE  (8)
+ 
+// Values for osrs_p & osrs_t fields of CTRL_MEAS register.
+#define BME280_SKIP  (0)
+#define BME280_OVERSAMPLING_1X  (1)
+#define BME280_OVERSAMPLING_2X  (2)
+#define BME280_OVERSAMPLING_4X  (3)
+#define BME280_OVERSAMPLING_8X  (4)
+#define BME280_OVERSAMPLING_16X  (5)
+ 
+// Values for mode field of CTRL_MEAS register.
+#define BME280_MODE_SLEEP  (0)
+#define BME280_MODE_FORCED  (1)
+#define BME280_MODE_NORMAL  (3)
+ 
+// Value for RESET register.
+#define BME280_RESET  (0xb6)
+ 
+// Value of ID register.
+#define BME280_ID  (0x60)
+ 
+// Values for t_sb field of CONFIG register
+#define BME280_STANDBY_500_US  (0)
+#define BME280_STANDBY_10_MS  (6)
+#define BME280_STANDBY_20_MS  (7)
+#define BME280_STANDBY_63_MS  (1)
+#define BME280_STANDBY_125_MS  (2)
+#define BME280_STANDBY_250_MS  (3)
+#define BME280_STANDBY_500_MS  (4)
+#define BME280_STANDBY_1000_MS  (5)
+ 
+// Values for filter field of CONFIG register
+#define BME280_FILTER_OFF  (0)
+#define BME280_FILTER_COEFF_2  (1)
+#define BME280_FILTER_COEFF_4  (2)
+#define BME280_FILTER_COEFF_8  (3)
+#define BME280_FILTER_COEFF_16  (4)
+ 
+ 
+// I2C write function must support repeated start to avoid interruption of transactions.
+// User-provided function to write data_size bytes from buffer p_data to I2C device at bus address i2c_address.
+// Provide empty function if not used.
+extern void i2cWrite(uint8_t i2c_address, uint8_t *p_data, uint8_t data_size, uint8_t repeated_start);
+// User-provided function to read data_size bytes from I2C device at bus address i2c_address to buffer p_data.
+// Provide empty function if not used.
+extern void i2cRead(uint8_t i2c_address, uint8_t *p_data, uint8_t data_size);
+ 
+// SPI functions must activate (make low) BME280 CSB pin before doing a transfer
+// and deactivate it (make high) when done.
+// User-provided function to write data_size bytes from buffer p_data to SPI device.
+// Provide empty function if not used.
+extern void spiWrite(uint8_t *p_data, uint8_t data_size);
+// User-provided function to read data_size bytes from SPI device to buffer p_data.
+// Provide empty function if not used.
+extern void spiRead(uint8_t *p_data, uint8_t data_size);
+ 
+ 
+class BME280
+{
+public:
+  BME280(void);
+  uint8_t begin(uint8_t i2cAddress=0); // I2C address not set means SPI.
+ 
+  void readCalibrationData(void);
+  uint8_t readId(void);
+  uint8_t readFrom(uint8_t reg, uint8_t data_size, uint8_t *p_data);
+ 
+  void read(void);
+ 
+  // If using floating points, values are scaled, if not then
+  // temperature is 100*T, pressure is Pa en humidity is 1024*%RH
+  temperature_t temperature(void) { return _temperature; } // [degrees Celsius] or 100*[degrees Celsius]
+  pressure_t pressure(void) { return _pressure; } // [Pa]
+  humidity_t humidity(void) { return _humidity; } // [%RH] or 1024*[%RH]
+ 
+  void writeControlRegisters(uint8_t osrs_t, uint8_t osrs_p, uint8_t osrs_h, uint8_t mode);
+  void writeConfigRegister(uint8_t t_sb, uint8_t filter, uint8_t spi);
+ 
+  void reset(void);
+ 
+private:
+  uint8_t _i2c_address;
+ 
+  void busWrite(uint8_t *p_data, uint8_t data_size, uint8_t repeated_start);
+  void busRead(uint8_t *p_data, uint8_t data_size);
+ 
+  // Calibration data.
+  uint16_t _dig_T1;
+  int16_t _dig_T2;
+  int16_t _dig_T3;
+  uint16_t _dig_P1;
+  int16_t _dig_P2;
+  int16_t _dig_P3;
+  int16_t _dig_P4;
+  int16_t _dig_P5;
+  int16_t _dig_P6;
+  int16_t _dig_P7;
+  int16_t _dig_P8;
+  int16_t _dig_P9;
+  uint8_t _dig_H1;
+  int16_t _dig_H2;
+  uint8_t _dig_H3;
+  int16_t _dig_H4;
+  int16_t _dig_H5;
+  int8_t _dig_H6;
+  void clearCalibrationData(void);
+ 
+  uint8_t readUint8(uint8_t reg);
+  uint16_t readUint16(uint8_t reg);
+ 
+  int32_t assembleRawValue(uint8_t *p_data, uint8_t has_xlsb);
+ 
+  int32_t _t_fine;
+ 
+  temperature_t compensateTemperature(int32_t adc_T);
+  pressure_t compensatePressure(int32_t adc_P);
+  humidity_t compensateHumidity(int32_t adc_H);
+ 
+  temperature_t _temperature;
+  pressure_t _pressure;
+  humidity_t _humidity;
+};
+ 
+ 
+#endif /* __BME280_H__*/