Library for the BMP085 barometer.
Dependents: Barometer-Example IOT_Repository
BMP085.cpp
- Committer:
- asmellby
- Date:
- 2015-11-18
- Revision:
- 1:33acd2e1edab
- Parent:
- 0:fb197da45ba8
File content as of revision 1:33acd2e1edab:
#include "BMP085.h" void BMP085::init(void) { _callback.attach(this, &BMP085::_callback_handler); _cal_data.ac1 = read_cal_register(BMP085_CAL_AC1); _cal_data.ac2 = read_cal_register(BMP085_CAL_AC2); _cal_data.ac3 = read_cal_register(BMP085_CAL_AC3); _cal_data.ac4 = read_cal_register(BMP085_CAL_AC4); _cal_data.ac5 = read_cal_register(BMP085_CAL_AC5); _cal_data.ac6 = read_cal_register(BMP085_CAL_AC6); _cal_data.b1 = read_cal_register(BMP085_CAL_B1); _cal_data.b2 = read_cal_register(BMP085_CAL_B2); _cal_data.mb = read_cal_register(BMP085_CAL_MB); _cal_data.mc = read_cal_register(BMP085_CAL_MC); _cal_data.md = read_cal_register(BMP085_CAL_MD); } uint16_t BMP085::read_cal_register(BMP085_Register reg) { _tx_buf[0] = reg; _state = BMP085_BUSY; _i2c.transfer(BMP085_ADDR, (char*)_tx_buf, 1, (char*)_rx_buf, 2, _callback); while(_state != BMP085_IDLE) { sleep(); } return (_rx_buf[0] << 8) | _rx_buf[1]; } uint16_t BMP085::read_uc_temperature(void) { LowPowerTimeout delay; _tx_buf[0] = BMP085_CTRL; _tx_buf[1] = BMP085_CMD_READ_TEMP; _state = BMP085_BUSY; _i2c.transfer(BMP085_ADDR, (char*)_tx_buf, 2, (char*)NULL, 0, _callback); while(_state != BMP085_IDLE) { sleep(); } _state = BMP085_BUSY; delay.attach(this, &BMP085::_callback_handler, 0.01); while(_state != BMP085_IDLE) { sleep(); } _tx_buf[0] = BMP085_DATA_TEMP; _state = BMP085_BUSY; _i2c.transfer(BMP085_ADDR, (char*)_tx_buf, 1, (char*)_rx_buf, 2, _callback); while(_state != BMP085_IDLE) { sleep(); } return (_rx_buf[0] << 8) | _rx_buf[1]; } uint32_t BMP085::read_uc_pressure(void) { LowPowerTimeout delay; _tx_buf[0] = BMP085_CTRL; _tx_buf[1] = BMP085_CMD_READ_PRESSURE + ((uint8_t)_mode << 6); _state = BMP085_BUSY; _i2c.transfer(BMP085_ADDR, (char*)_tx_buf, 2, (char*)NULL, 0, _callback); while(_state != BMP085_IDLE) { sleep(); } _state = BMP085_BUSY; delay.attach(this, &BMP085::_callback_handler, 0.02); while(_state != BMP085_IDLE) { sleep(); } _tx_buf[0] = BMP085_DATA_PRESSURE; _state = BMP085_BUSY; _i2c.transfer(BMP085_ADDR, (char*)_tx_buf, 1, (char*)_rx_buf, 3, _callback); while(_state != BMP085_IDLE) { sleep(); } return ((_rx_buf[0] << 16) | (_rx_buf[1] << 8) | _rx_buf[2]) >> (8 - (uint8_t)_mode); } void BMP085::measure() { int t, p, ut, up, x1, x2, x3, b3, b5, b6; uint32_t b4, b7; ut = read_uc_temperature(); x1 = (ut - _cal_data.ac6) * _cal_data.ac5 / (1 << 15); x2 = (int)_cal_data.mc * (1 << 11) / (x1 + _cal_data.md); b5 = x1 + x2; t = (b5 + 8) / (1 << 4); _temperature = (float)t / 10.0; up = read_uc_pressure(); b6 = b5 - 4000; x1 = (_cal_data.b2 * (b6 * b6 / (1 << 12))) / (1 << 11); x2 = _cal_data.ac2 * b6 / (1 << 11); x3 = x1 + x2; b3 = ((((unsigned int)_cal_data.ac1 * 4 + x3) << (int)_mode) + 2) / 4; x1 = _cal_data.ac3 * b6 / (1 << 13); x2 = (_cal_data.b1 * (b6 * b6 / (1 << 12))) / (1 << 16); x3 = ((x1 + x2) + 2) / (1 << 2); b4 = _cal_data.ac4 * (unsigned int)(x3 + 32768) / (1 << 15); b7 = ((unsigned int)up - b3) * (50000 >> (int)_mode); if (b7 < (unsigned int)0x80000000) { p = (b7 * 2) / b4; } else { p = (b7 / b4) * 2; } x1 = (p / (1 << 8)) * (p / (1 << 8)); x1 = (x1 * 3038) / (1 << 16); x2 = (-7357 * p) / (1 << 16); p = p + (x1 + x2 + 3791) / (1 << 4); _pressure = (float)p / 100.0; } void BMP085::_callback_handler(int event) { _state = BMP085_IDLE; } void BMP085::_callback_handler() { _state = BMP085_IDLE; }