f0c43ff5d5
The BME280 is close to compatible with the existing BMP280 and extends it with support for measuring humidity, so support has been bundled into the bmp280 driver. The example now auto-detects the device and displays the humidity for the BME280. The I2C bus initialization has been moved out of the bmp280 driver to support multiple devices. The check-id and reset logic has been bundled into the driver initialization. It needs to be re-initialized after reset anyway and the chip-id is need to initialize it, just re-initialize to reset. Support has been added for multiple devices. The calibration data storage needs to be managed by the caller rather than static data. The caller can choose the I2C address to allow two BMx280 devices to be used on the same I2C bus. An interface has been added to return the measurement values in an integer fixed float format. The float format interface is still there. All the values are read in one I2C transaction to ensure they are a consistent set. Renamed bmp280_calib_t to bmp280_t, and removed read_register8.
187 lines
5.7 KiB
C
187 lines
5.7 KiB
C
/**
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* The MIT License (MIT)
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*
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* Copyright (c) 2016 sheinz (https://github.com/sheinz)
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef __BMP280_H__
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#define __BMP280_H__
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#include <stdint.h>
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#include <stdbool.h>
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/**
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* Uncomment to enable debug output.
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*/
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// #define BMP280_DEBUG
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/**
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* BMP280 or BME280 address is 0x77 if SDO pin is high, and is 0x76 if
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* SDO pin is low.
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*/
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#define BMP280_I2C_ADDRESS_0 0x76
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#define BMP280_I2C_ADDRESS_1 0x77
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#define BMP280_CHIP_ID 0x58 /* BMP280 has chip-id 0x58 */
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#define BME280_CHIP_ID 0x60 /* BME280 has chip-id 0x60 */
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/**
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* Mode of BMP280 module operation.
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* Forced - Measurement is initiated by user.
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* Normal - Continues measurement.
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*/
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typedef enum {
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BMP280_MODE_SLEEP = 0,
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BMP280_MODE_FORCED = 1,
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BMP280_MODE_NORMAL = 3
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} BMP280_Mode;
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typedef enum {
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BMP280_FILTER_OFF = 0,
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BMP280_FILTER_2 = 1,
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BMP280_FILTER_4 = 2,
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BMP280_FILTER_8 = 3,
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BMP280_FILTER_16 = 4
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} BMP280_Filter;
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/**
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* Pressure oversampling settings
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*/
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typedef enum {
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BMP280_ULTRA_LOW_POWER = 1, /* oversampling x1 */
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BMP280_LOW_POWER = 2, /* oversampling x2 */
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BMP280_STANDARD = 3, /* oversampling x4 */
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BMP280_HIGH_RES = 4, /* oversampling x8 */
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BMP280_ULTRA_HIGH_RES = 5 /* oversampling x16 */
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} BMP280_Oversampling;
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/**
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* Stand by time between measurements in normal mode
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*/
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typedef enum {
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BMP280_STANDBY_05 = 0, /* stand by time 0.5ms */
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BMP280_STANDBY_62 = 1, /* stand by time 62.5ms */
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BMP280_STANDBY_125 = 2, /* stand by time 125ms */
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BMP280_STANDBY_250 = 3, /* stand by time 250ms */
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BMP280_STANDBY_500 = 4, /* stand by time 500ms */
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BMP280_STANDBY_1000 = 5, /* stand by time 1s */
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BMP280_STANDBY_2000 = 6, /* stand by time 2s BMP280, 10ms BME280 */
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BMP280_STANDBY_4000 = 7, /* stand by time 4s BMP280, 20ms BME280 */
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} BMP280_StandbyTime;
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/**
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* Configuration parameters for BMP280 module.
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* Use function bmp280_init_default_params to use default configuration.
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*/
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typedef struct {
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BMP280_Mode mode;
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BMP280_Filter filter;
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BMP280_Oversampling oversampling; // pressure oversampling
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BMP280_Oversampling oversampling_humidity;
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BMP280_StandbyTime standby;
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} bmp280_params_t;
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typedef struct {
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uint16_t dig_T1;
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int16_t dig_T2;
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int16_t dig_T3;
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uint16_t dig_P1;
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int16_t dig_P2;
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int16_t dig_P3;
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int16_t dig_P4;
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int16_t dig_P5;
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int16_t dig_P6;
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int16_t dig_P7;
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int16_t dig_P8;
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int16_t dig_P9;
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/* Humidity compensation for BME280 */
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uint8_t dig_H1;
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int16_t dig_H2;
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uint8_t dig_H3;
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int16_t dig_H4;
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int16_t dig_H5;
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int8_t dig_H6;
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uint8_t i2c_addr; /* I2C address. */
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uint8_t id; /* Chip ID */
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} bmp280_t;
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/**
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* Initialize default parameters.
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* Default configuration:
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* mode: NORAML
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* filter: OFF
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* oversampling: x4
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* standby time: 250ms
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*/
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void bmp280_init_default_params(bmp280_params_t *params);
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/**
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* Initialize BMP280 module, probes for the device, soft resets the device,
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* reads the calibration constants, and configures the device using the supplied
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* parameters. Returns true on success otherwise false.
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*
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* The I2C address is assumed to have been initialized in the dev, and
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* may be either BMP280_I2C_ADDRESS_0 or BMP280_I2C_ADDRESS_1. If the I2C
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* address is unknown then try initializing each in turn.
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*
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* This may be called again to soft reset the device and initialize it again.
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*/
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bool bmp280_init(bmp280_t *dev, bmp280_params_t *params);
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/**
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* Start measurement in forced mode.
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* The module remains in forced mode after this call.
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* Do not call this method in normal mode.
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*/
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bool bmp280_force_measurement(bmp280_t *dev);
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/**
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* Check if BMP280 is busy with measuring temperature/pressure.
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* Return true if BMP280 is busy.
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*/
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bool bmp280_is_measuring(bmp280_t *dev);
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/**
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* Read compensated temperature and pressure data:
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*
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* Temperature in degrees Celsius times 100.
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*
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* Pressure in Pascals in fixed point 24 bit integer 8 bit fraction format.
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*
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* Humidity is optional and only read for the BME280, in percent relative
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* humidity as a fixed point 22 bit interger and 10 bit fraction format.
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*/
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bool bmp280_read_fixed(bmp280_t *dev, int32_t *temperature,
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uint32_t *pressure, uint32_t *humidity);
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/**
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* Read compensated temperature and pressure data:
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* Temperature in degrees Celsius.
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* Pressure in Pascals.
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* Humidity is optional and only read for the BME280, in percent relative
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* humidity.
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*/
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bool bmp280_read_float(bmp280_t *dev, float *temperature,
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float *pressure, float *humidity);
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#endif // __BMP280_H__
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