BMP280 Sensor Library but replaced original getTemperature Routine as it was returning strange values
Fork of BMP280 by
BMP280.cpp
- Committer:
- 12104404
- Date:
- 2016-04-13
- Revision:
- 6:d03826fe1062
- Parent:
- 5:7139d5accbc3
- Child:
- 7:c72b726c7dc9
File content as of revision 6:d03826fe1062:
/** * BME280 Combined humidity and pressure sensor library * * @author Toyomasa Watarai * @version 1.0 * @date 06-April-2015 * * Library for "BME280 temperature, humidity and pressure sensor module" from Switch Science * https://www.switch-science.com/catalog/2236/ * * For more information about the BME280: * http://ae-bst.resource.bosch.com/media/products/dokumente/bme280/BST-BME280_DS001-10.pdf */ #include "mbed.h" #include "BMP280.h" BME280::BME280(PinName sda, PinName scl, char slave_adr) : i2c_p(new I2C(sda, scl)), i2c(*i2c_p), address(slave_adr), t_fine(0) { initialize(); } BME280::BME280(I2C &i2c_obj, char slave_adr) : i2c_p(NULL), i2c(i2c_obj), address(slave_adr), t_fine(0) { initialize(); } BME280::~BME280() { if (NULL != i2c_p) delete i2c_p; } void BME280::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 BME280::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 BME280::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); } /*float BME280::getHumidity() { uint32_t hum_raw; float humf; char cmd[4]; cmd[0] = 0xfd; // hum_msb i2c.write(address, cmd, 1); i2c.read(address, &cmd[1], 2); hum_raw = (cmd[1] << 8) | cmd[2]; int32_t v_x1; v_x1 = t_fine - 76800; v_x1 = (((((hum_raw << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * v_x1)) + ((int32_t)16384)) >> 15) * (((((((v_x1 * (int32_t)dig_H6) >> 10) * (((v_x1 * ((int32_t)dig_H3)) >> 11) + 32768)) >> 10) + 2097152) * (int32_t)dig_H2 + 8192) >> 14)); v_x1 = (v_x1 - (((((v_x1 >> 15) * (v_x1 >> 15)) >> 7) * (int32_t)dig_H1) >> 4)); v_x1 = (v_x1 < 0 ? 0 : v_x1); v_x1 = (v_x1 > 419430400 ? 419430400 : v_x1); humf = (float)(v_x1 >> 12); return (humf/1024.0f); }*/