OS6. i2s BME280 library, also works with BMP280 without Humidity. See BME280.h for example code.
Diff: BME280.cpp
- Revision:
- 0:19fab6c64964
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/BME280.cpp Sat Jan 02 10:32:48 2021 +0000 @@ -0,0 +1,183 @@ +#include "BME280.h" + +BME::BME(PinName sda, PinName scl, char slave_adr) : bme(sda, scl) +{ + address=slave_adr; + bme.frequency(100000); +} + +void BME::initialize() +{ + char cmd[18]; + wait_us(5000); + + if(_debug)printf("\033[0m\033[2J\033[H ++++ BME-P register's ++++\r\n\n"); + + cmd[0] = 0xF2; // ctrl_hum + cmd[1] = 0x01; // Humidity oversampling x1 + bme.write(address, cmd, 2); + + cmd[0] = 0xF4; // ctrl_meas + cmd[1] = 0x27; // Temparature oversampling x1, Pressure oversampling x1, Normal mode + bme.write(address, cmd, 2); + + cmd[0] = 0xF5; // config + cmd[1] = 0xa0; // Standby 1000ms, Filter off + bme.write(address, cmd, 2); + + // sensor registers + if(_debug)printf("chip_id = 0x%x\n\n", chip_id); + + cmd[0] = 0x88; // read dig_T calibration regs + bme.write(address, cmd, 1); + bme.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]; + if(_debug)printf("Temp Cal reg's:\nT1 = 0x%x\nT2 = 0x%x\nT3 = 0x%x\n\n", dig_T1, dig_T2, dig_T3); + + cmd[0] = 0x8E; // read dig_P calibration regs + bme.write(address, cmd, 1); + bme.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]; + if(_debug)printf("Pressure Cal reg's:\nP1 = 0x%x\nP2 = 0x%x\nP3 = 0x%x\nP4 = 0x%x\n", dig_P1, dig_P2, dig_P3, dig_P4); + if(_debug)printf("P5 = 0x%x\nP6 = 0x%x\nP7 = 0x%x\nP8 = 0x%x\nP9 = 0x%x\n\n", dig_P5, dig_P6, dig_P7, dig_P8, dig_P9); + + if(chip_id == 0x60){ // Only BME280 has Humidity + cmd[0] = 0xA1; // read dig_H calibration LSB regs + bme.write(address, cmd, 1); + bme.read(address, cmd, 1); + cmd[1] = 0xE1; // read dig_H calibration MSB regs + bme.write(address, &cmd[1], 1); + bme.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]; + if(_debug)printf("Humidity Cal reg's:\nH1 = 0x%x\nH2 = 0x%x\nH3 = 0x%x\n", dig_H1, dig_H2, dig_H3); + if(_debug)printf("H4 = 0x%x\nH5 = 0x%x\nH6 = 0x%x\n", dig_H4, dig_H5, dig_H6); + } +} + +int BME::init() +{ + char cmd[2]; + cmd[0] = 0xE0; // reset reg + cmd[1] = 0xB6; + bme.write(address, cmd, 2); + if(chipID()){ + initialize(); + return chip_id; + } + else return 0; +} + +int BME::chipID() +{ + char cmd[1]; + cmd[0] = 0xD0; // chip_id + bme.write(address, cmd, 1); + cmd[0] = 0x00; + bme.read(address, cmd, 1); + chip_id = cmd[0]; + return chip_id; +} + +float BME::getTemperature() +{ + if(!chipID()){init();} // check if live sensor + + int32_t var1, var2, T, adc_T; + float temp; + char cmd[4]; + cmd[0] = 0xFA; // temp_msb + bme.write(address, cmd, 1); + bme.read(address, &cmd[1], 3); + + adc_T = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4); + + var1 = ((((adc_T>>3) - ((int32_t)dig_T1 <<1))) * + ((int32_t)dig_T2)) >> 11; + var2 = (((((adc_T>>4) - ((int32_t)dig_T1)) * + ((adc_T>>4) - ((int32_t)dig_T1))) >> 12) * + ((int32_t)dig_T3)) >> 14; + t_fine = var1 + var2; + T = (t_fine * 5 + 128) >> 8; + temp = T/100.0; + if(temp>-41 && temp<86){ // return temperature if within device limits. + return temp; + } + else return 99.99; // error value +} + +float BME::getPressure() +{ + if(!chipID()){init();} // check if live sensor + + uint32_t adc_P; + int64_t var1, var2, p; + float press; + char cmd[4]; + cmd[0] = 0xF7; // press_msb + bme.write(address, cmd, 1); + bme.read(address, &cmd[1], 3); + + adc_P = (cmd[1] << 12) | (cmd[2] << 4) | (cmd[3] >> 4); + + var1 = ((int64_t)t_fine) - 128000; + var2 = var1 * var1 * (int64_t)dig_P6; + var2 = var2 + ((var1 * (int64_t)dig_P5) << 17); + var2 = var2 + (((int64_t)dig_P4) << 35); + var1 = ((var1 * var1 * (int64_t)dig_P3)>>8)+((var1 * (int64_t)dig_P2)<<12); + var1 = (((((int64_t)1)<<47)+var1)) * ((int64_t)dig_P1)>>33; + if (var1 == 0) {return 0;} + p = 1048576-adc_P; + p = (((p<<31)-var2)*3125)/var1; + var1 = (((int64_t)dig_P9) * (p>>13) * (p>>13))>>25; + var2 = (((int64_t)dig_P8) * p)>>19; + p = ((p + var1 + var2)>>8) + (((int64_t)dig_P7)<<4); + press = ((float)p/256)/100.0f; + if(press>300 && press<1100){ // return temperature if within device limits. + return press; + } + else return 9999; // error value +} + +float BME::getHumidity() +{ + if(!chipID()){init();} // check if live sensor + + uint32_t humid_raw; + int32_t v_x1r; + float humid; + char cmd[4]; + cmd[0] = 0xfd; // hum_msb + bme.write(address, cmd, 1); + bme.read(address, &cmd[1], 2); + + humid_raw = (cmd[1] << 8) | cmd[2]; + + v_x1r = (t_fine - 76800); + v_x1r = (((((humid_raw << 14) -(((int32_t)dig_H4) << 20) - (((int32_t)dig_H5) * + v_x1r)) + ((int32_t)16384)) >> 15) * (((((((v_x1r * + (int32_t)dig_H6) >> 10) * (((v_x1r * ((int32_t)dig_H3)) >> 11) + + 32768)) >> 10) + 2097152) * (int32_t)dig_H2 + 8192) >> 14)); + v_x1r = (v_x1r - (((((v_x1r >> 15) * (v_x1r >> 15)) >> 7) * + (int32_t)dig_H1) >> 4)); + v_x1r = (v_x1r < 0 ? 0 : v_x1r); + v_x1r = (v_x1r > 419430400 ? 419430400 : v_x1r); + + humid = ((float)(v_x1r >> 12))/1024.0f; + + return humid; +}