Class for using BMP180 Bosch Pressure sensor
Dependents: ILI9341_Clock_Nucleo IoT-Polytech-Upmc
BMP180.cpp
- Committer:
- harrypowers
- Date:
- 2013-11-26
- Revision:
- 0:b899fe37ce17
- Child:
- 1:4c6b41f1203d
File content as of revision 0:b899fe37ce17:
#include "BMP180.h" BMP180::BMP180(PinName sda, PinName scl) : bmp180i2c(sda,scl) { bmp180i2c.frequency(BMP180FREQ); oversampling_setting = OVERSAMPLING_HIGH_RESOLUTION; rReg[0] = 0; rReg[1] = 0; rReg[2] = 0; wReg[0] = 0; wReg[1] = 0; w[0] = 0xF4; w[1] = 0xF4; cmd = CMD_READ_CALIBRATION; // EEPROM calibration command for (int i = 0; i < EEprom; i++) { // read the 22 registers of the EEPROM bmp180i2c.write(BMP180ADDR, &cmd, 1); bmp180i2c.read(BMP180ADDR, rReg, 1); data[i] = rReg[0]; cmd += 1; wait_ms(10); } // parameters AC1-AC6 //The calibration is partioned in 11 words of 16 bits, each of them representing a coefficient ac1 = (data[0] <<8) | data[1]; // AC1(0xAA, 0xAB)... and so on ac2 = (data[2] <<8) | data[3]; ac3 = (data[4] <<8) | data[5]; ac4 = (data[6] <<8) | data[7]; ac5 = (data[8] <<8) | data[9]; ac6 = (data[10] <<8) | data[11]; // parameters B1,B2 b1 = (data[12] <<8) | data[13]; b2 = (data[14] <<8) | data[15]; // parameters MB,MC,MD mb = (data[16] <<8) | data[17]; mc = (data[18] <<8) | data[19]; md = (data[20] <<8) | data[21]; } BMP180::~BMP180() { } int BMP180::startTemperature() // Start temperature measurement { int errors = 0; errors += bmp180i2c.write(BMP180ADDR, w, 2); wReg[0] = 0xF4; wReg[1] = 0x2E; errors += bmp180i2c.write(BMP180ADDR, wReg, 2); // write 0x2E in reg 0XF4 return(errors); } int BMP180::readTemperature(long *t) // Get the temperature reading that was taken in startTemperature() but ensure 4.5 ms time has elapsed { int errors = 0; cmd = CMD_READ_VALUE; // 0xF6 errors += bmp180i2c.write(BMP180ADDR, &cmd, 1); // set pointer on 0xF6 before reading it? errors += bmp180i2c.read(BMP180ADDR, rReg, 2); // read 0xF6 (MSB) and 0xF7 (LSB)// rReg is 3 long though *t = (rReg[0] << 8) | rReg[1]; // UT = MSB << 8 + LSB return(errors); } int BMP180::startPressure(int oversample) // Start pressure measurement! Note oversample will vary the time to complete this measurement. See defines above for oversampling constants to use! { int errors = 0; int uncomp_pressure_cmd = 0x34 + (oversample<<6); errors = bmp180i2c.write(BMP180ADDR, w, 2); wReg[0] = 0xF4; wReg[1] = uncomp_pressure_cmd; errors += bmp180i2c.write(BMP180ADDR, wReg, 2); return(errors); } int BMP180::readPressure(long *p) // Get the pressure reading that was taken in startPressure() but ensure time for the measurement to complete { int errors = 0; cmd = CMD_READ_VALUE; // 0xF6 errors += bmp180i2c.write(BMP180ADDR, &cmd, 1); errors += bmp180i2c.read(BMP180ADDR, rReg, 3); // read 0xF6 (MSB), 0xF7 (LSB), 0xF8 (XLSB) *p = ((rReg[0] << 16) | (rReg[1] << 8) | rReg[2]) >> (8 - oversampling_setting); return(errors); } /* int BMP180::rTemp(long *ut) { int errors = 0; errors = bmp180i2c.write(BMP180ADDR, w, 2); wReg[0] = 0xF4; wReg[1] = 0x2E; errors += bmp180i2c.write(BMP180ADDR, wReg, 2); // write 0x2E in reg 0XF4 wait_ms(4.5); cmd = CMD_READ_VALUE; // 0xF6 errors += bmp180i2c.write(BMP180ADDR, &cmd, 1); // set pointer on 0xF6 before reading it? errors += bmp180i2c.read(BMP180ADDR, rReg, 2); // read 0xF6 (MSB) and 0xF7 (LSB)// rReg is 3 long though *ut = (rReg[0] << 8) | rReg[1]; // UT = MSB << 8 + LSB return(errors); } int BMP180::rPressure(long *up) { int errors = 0; errors = bmp180i2c.write(BMP180ADDR, w, 2); int uncomp_pressure_cmd = 0x34 + (oversampling_setting<<6); wReg[0] = 0xF4; wReg[1] = uncomp_pressure_cmd; errors += bmp180i2c.write(BMP180ADDR, wReg, 2); switch (oversampling_setting) { case OVERSAMPLING_ULTRA_LOW_POWER: wait_ms(4.5); break; case OVERSAMPLING_STANDARD: wait_ms(7.5); break; case OVERSAMPLING_HIGH_RESOLUTION: wait_ms(13.5); break; case OVERSAMPLING_ULTRA_HIGH_RESOLUTION: wait_ms(25.5); break; } cmd = CMD_READ_VALUE; // 0xF6 errors += bmp180i2c.write(BMP180ADDR, &cmd, 1); errors += bmp180i2c.read(BMP180ADDR, rReg, 3); // read 0xF6 (MSB), 0xF7 (LSB), 0xF8 (XLSB) *up = ((rReg[0] << 16) | (rReg[1] << 8) | rReg[2]) >> (8 - oversampling_setting); return(errors); } */ int BMP180::readTP(long *t, long *p, int oversample) // get both temperature and pressure calculations that are compensated { int errors = 0; errors += BMP180::startTemperature(); wait_ms(4.5); errors += BMP180::readTemperature(t); errors += BMP180::startPressure(oversample); switch (oversampling_setting) { case OVERSAMPLING_ULTRA_LOW_POWER: wait_ms(4.5); break; case OVERSAMPLING_STANDARD: wait_ms(7.5); break; case OVERSAMPLING_HIGH_RESOLUTION: wait_ms(13.5); break; case OVERSAMPLING_ULTRA_HIGH_RESOLUTION: wait_ms(25.5); break; } errors += BMP180::readPressure(p); return(errors); }