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Dependencies: HCSR04_2 MPU6050_2 mbed SDFileSystem3
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Diff: BMP280/BMP280.cpp
- Revision:
- 0:17f575135219
diff -r 000000000000 -r 17f575135219 BMP280/BMP280.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/BMP280/BMP280.cpp Fri Sep 07 04:11:48 2018 +0000 @@ -0,0 +1,165 @@ +/** + * BMP280 Combined humidity and pressure sensor library + * + * @author Toyomasa Watarai + * @version 1.0 + * @date 06-April-2015 + * + * Library for "BMP280 temperature, humidity and pressure sensor module" from Switch Science + * https://www.switch-science.com/catalog/2236/ + * + * For more information about the BMP280: + * http://ae-bst.resource.bosch.com/media/products/dokumente/BMP280/BST-BMP280_DS001-10.pdf + */ + +#include "mbed.h" +#include "BMP280.h" + +BMP280::BMP280(PinName sda, PinName scl, char slave_adr) + : + i2c_p(new I2C(sda, scl)), + i2c(*i2c_p), + address(slave_adr), + t_fine(0) +{ + initialize(); +} + +BMP280::BMP280(I2C &i2c_obj, char slave_adr) + : + i2c_p(NULL), + i2c(i2c_obj), + address(slave_adr), + t_fine(0) +{ + initialize(); +} + +BMP280::~BMP280() +{ + if (NULL != i2c_p) + delete i2c_p; +} + +void BMP280::initialize() +{ + char cmd[18]; + + cmd[0] = 0xf2; // ctrl_hum + cmd[1] = 0x01; // Humidity oversampling x1 + i2c.write(address, cmd, 2); + + cmd[0] = 0xf4; // ctrl_meas + cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode + i2c.write(address, cmd, 2); + + cmd[0] = 0xf5; // config + cmd[1] = 0xa0; // Standby 1000ms, Filter off + i2c.write(address, cmd, 2); + + cmd[0] = 0x88; // read dig_T regs + i2c.write(address, cmd, 1); + i2c.read(address, cmd, 6); + + dig_T1 = (cmd[1] << 8) | cmd[0]; + dig_T2 = (cmd[3] << 8) | cmd[2]; + dig_T3 = (cmd[5] << 8) | cmd[4]; + + DEBUG_PRINT("dig_T = 0x%x, 0x%x, 0x%x\n", dig_T1, dig_T2, dig_T3); + + cmd[0] = 0x8E; // read dig_P regs + i2c.write(address, cmd, 1); + i2c.read(address, cmd, 18); + + dig_P1 = (cmd[ 1] << 8) | cmd[ 0]; + dig_P2 = (cmd[ 3] << 8) | cmd[ 2]; + dig_P3 = (cmd[ 5] << 8) | cmd[ 4]; + dig_P4 = (cmd[ 7] << 8) | cmd[ 6]; + dig_P5 = (cmd[ 9] << 8) | cmd[ 8]; + dig_P6 = (cmd[11] << 8) | cmd[10]; + dig_P7 = (cmd[13] << 8) | cmd[12]; + dig_P8 = (cmd[15] << 8) | cmd[14]; + dig_P9 = (cmd[17] << 8) | cmd[16]; + + DEBUG_PRINT("dig_P = 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n", dig_P1, dig_P2, dig_P3, dig_P4, dig_P5, dig_P6, dig_P7, dig_P8, dig_P9); + + /* cmd[0] = 0xA1; // read dig_H regs + i2c.write(address, cmd, 1); + i2c.read(address, cmd, 1); + cmd[1] = 0xE1; // read dig_H regs + i2c.write(address, &cmd[1], 1); + i2c.read(address, &cmd[1], 7); + + dig_H1 = cmd[0]; + dig_H2 = (cmd[2] << 8) | cmd[1]; + dig_H3 = cmd[3]; + dig_H4 = (cmd[4] << 4) | (cmd[5] & 0x0f); + dig_H5 = (cmd[6] << 4) | ((cmd[5]>>4) & 0x0f); + dig_H6 = cmd[7]; + + DEBUG_PRINT("dig_H = 0x%x, 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n", dig_H1, dig_H2, dig_H3, dig_H4, dig_H5, dig_H6); +*/ +} + +float BMP280::getTemperature() +{ + uint32_t temp_raw; + float tempf; + char cmd[4]; + + cmd[0] = 0xfa; // temp_msb + i2c.write(address, cmd, 1); + i2c.read(address, &cmd[1], 3); + + temp_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4); + + int32_t temp; + + temp = + (((((temp_raw >> 3) - (dig_T1 << 1))) * dig_T2) >> 11) + + ((((((temp_raw >> 4) - dig_T1) * ((temp_raw >> 4) - dig_T1)) >> 12) * dig_T3) >> 14); + + t_fine = temp; + temp = (temp * 5 + 128) >> 8; + tempf = (float)temp; + + return (tempf/100.0f); +} + +float BMP280::getPressure() +{ + uint32_t press_raw; + float pressf; + char cmd[4]; + + cmd[0] = 0xf7; // press_msb + i2c.write(address, cmd, 1); + i2c.read(address, &cmd[1], 3); + + press_raw = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4); + + int32_t var1, var2; + uint32_t press; + + var1 = (t_fine >> 1) - 64000; + var2 = (((var1 >> 2) * (var1 >> 2)) >> 11) * dig_P6; + var2 = var2 + ((var1 * dig_P5) << 1); + var2 = (var2 >> 2) + (dig_P4 << 16); + var1 = (((dig_P3 * (((var1 >> 2)*(var1 >> 2)) >> 13)) >> 3) + ((dig_P2 * var1) >> 1)) >> 18; + var1 = ((32768 + var1) * dig_P1) >> 15; + if (var1 == 0) { + return 0; + } + press = (((1048576 - press_raw) - (var2 >> 12))) * 3125; + if(press < 0x80000000) { + press = (press << 1) / var1; + } else { + press = (press / var1) * 2; + } + var1 = ((int32_t)dig_P9 * ((int32_t)(((press >> 3) * (press >> 3)) >> 13))) >> 12; + var2 = (((int32_t)(press >> 2)) * (int32_t)dig_P8) >> 13; + press = (press + ((var1 + var2 + dig_P7) >> 4)); + + pressf = (float)press; + return (pressf/100.0f); +} \ No newline at end of file