// // FILE: AGS02MA.cpp // AUTHOR: Rob Tillaart, Viktor Balint, Beanow // DATE: 2021-08-12 // VERSION: 0.4.2 // PURPOSE: Arduino library for AGS02MA TVOC sensor // URL: https://github.com/RobTillaart/AGS02MA #include "AGS02MA.h" // REGISTERS #define AGS02MA_DATA 0x00 #define AGS02MA_CALIBRATION 0x01 #define AGS02MA_VERSION 0x11 #define AGS02MA_SLAVE_ADDRESS 0x21 AGS02MA::AGS02MA(const uint8_t deviceAddress, TwoWire *wire) { _address = deviceAddress; _wire = wire; reset(); } bool AGS02MA::begin() { _startTime = millis(); // PREHEAT TIMING return isConnected(); } bool AGS02MA::isConnected() { _setI2CLowSpeed(); _wire->beginTransmission(_address); bool rv = ( _wire->endTransmission(true) == 0); _setI2CHighSpeed(); return rv; } void AGS02MA::reset() { _I2CResetSpeed = 100000; _startTime = millis(); _lastRead = 0; _lastPPB = 0; _mode = 255; _status = AGS02MA_OK; _error = AGS02MA_OK; } bool AGS02MA::setAddress(const uint8_t deviceAddress) { if ((deviceAddress < 10) or (deviceAddress > 119)) return false; _buffer[2] = _buffer[0] = deviceAddress; _buffer[3] = _buffer[1] = 0xFF ^ deviceAddress; _buffer[4] = _CRC8(_buffer, 4); if (_writeRegister(AGS02MA_SLAVE_ADDRESS)) { _address = deviceAddress; } return isConnected(); } uint8_t AGS02MA::getSensorVersion() { uint8_t version = 0xFF; if (_readRegister(AGS02MA_VERSION)) { // for (int i = 0; i < 5; i++) // { // Serial.print(_buffer[i]); // Serial.print('\t'); // } // Serial.println(); // unclear what the other bytes have for information. // datasheet names these 3 bytes as KEEP. // BUFFER VALUE MEANING // buffer [0] == 20 year ? // buffer [1] == 07 month ? // buffer [2] == 28 day ? // buffer [3] == 117 VERSION // buffer [4] == CRC version = _buffer[3]; if (_CRC8(_buffer, 5) != 0) { _error = AGS02MA_ERROR_CRC; } } return version; } uint32_t AGS02MA::getSensorDate() { uint32_t date = 0xFFFFFFFF; if (_readRegister(AGS02MA_VERSION)) { date = 0x20; date <<= 8; date += _bin2bcd(_buffer[0]); date <<= 8; date += _bin2bcd(_buffer[1]); date <<= 8; date += _bin2bcd(_buffer[2]); // version = _buffer[3]; if (_CRC8(_buffer, 5) != 0) { _error = AGS02MA_ERROR_CRC; } } return date; } bool AGS02MA::setPPBMode() { _buffer[0] = 0x00; _buffer[1] = 0xFF; _buffer[2] = 0x00; _buffer[3] = 0xFF; _buffer[4] = 0x30; if (_writeRegister(AGS02MA_DATA)) { _mode = 0; return true; } return false; } bool AGS02MA::setUGM3Mode() { _buffer[0] = 0x02; _buffer[1] = 0xFD; _buffer[2] = 0x02; _buffer[3] = 0xFD; _buffer[4] = 0x00; if (_writeRegister(AGS02MA_DATA)) { _mode = 1; return true; } return false; } uint32_t AGS02MA::readPPB() { uint32_t value = _readSensor(); if (_error == AGS02MA_OK) { _lastRead = millis(); _lastPPB = value; } else { value = _lastPPB; } return value; } uint32_t AGS02MA::readUGM3() { uint32_t value = _readSensor(); if (_error == AGS02MA_OK) { _lastRead = millis(); _lastUGM3 = value; } else { value = _lastUGM3; } return value; } bool AGS02MA::manualZeroCalibration(uint16_t value) { _buffer[0] = 0x00; _buffer[1] = 0x0C; _buffer[2] = (uint8_t) (value >> 8); _buffer[3] = (uint8_t) (value & 0x00FF); _buffer[4] = _CRC8(_buffer, 4); return _writeRegister(AGS02MA_CALIBRATION); } bool AGS02MA::getZeroCalibrationData(AGS02MA::ZeroCalibrationData &data) { if (!_readRegister(AGS02MA_CALIBRATION)) { return false; } if (_CRC8(_buffer, 5) != 0) { _error = AGS02MA_ERROR_CRC; return false; } _error = AGS02MA_OK; // Don't pollute the struct given to us, until we've handled all error cases. data.status = _getDataMSB(); data.value = _getDataLSB(); return true; } int AGS02MA::lastError() { int e = _error; _error = AGS02MA_OK; // reset error after read return e; } bool AGS02MA::readRegister(uint8_t address, AGS02MA::RegisterData ®) { if (!_readRegister(address)) { return false; } if (_CRC8(_buffer, 5) != 0) { _error = AGS02MA_ERROR_CRC; return false; } _error = AGS02MA_OK; // Don't pollute the struct given to us, until we've handled all error cases. reg.data[0] = _buffer[0]; reg.data[1] = _buffer[1]; reg.data[2] = _buffer[2]; reg.data[3] = _buffer[3]; reg.crc = _buffer[4]; reg.crcValid = true; // checked above. return true; } ///////////////////////////////////////////////////////// // // PRIVATE // uint32_t AGS02MA::_readSensor() { uint32_t value = 0; if (_readRegister(AGS02MA_DATA)) { _error = AGS02MA_OK; _status = _buffer[0]; if (_status & 0x01) { _error = AGS02MA_ERROR_NOT_READY; } value = _buffer[1] * 65536UL; value += _buffer[2] * 256; value += _buffer[3]; if (_CRC8(_buffer, 5) != 0) { _error = AGS02MA_ERROR_CRC; } } return value; } bool AGS02MA::_readRegister(uint8_t reg) { while (millis() - _lastRegTime < 30) yield(); _setI2CLowSpeed(); _wire->beginTransmission(_address); _wire->write(reg); _error = _wire->endTransmission(true); if (_error != 0) { // _error will be I2C error code _setI2CHighSpeed(); return false; } // TODO investigate async interface delay(30); if (_wire->requestFrom(_address, (uint8_t)5) != 5) { _error = AGS02MA_ERROR_READ; _setI2CHighSpeed(); return false; } for (uint8_t i = 0; i < 5; i++) { _buffer[i] = _wire->read(); } _error = AGS02MA_OK; _setI2CHighSpeed(); return true; } bool AGS02MA::_writeRegister(uint8_t reg) { while (millis() - _lastRegTime < 30) yield(); _lastRegTime = millis(); _setI2CLowSpeed(); _wire->beginTransmission(_address); _wire->write(reg); for (uint8_t i = 0; i < 5; i++) { _wire->write(_buffer[i]); } _error = _wire->endTransmission(true); _setI2CHighSpeed(); return (_error == 0); } void AGS02MA::_setI2CLowSpeed() { #if defined (__AVR__) // TWBR = 255; // == 30.4 KHz with TWSR = 0x00 TWBR = 78; // == 25.0 KHZ TWSR = 0x01; // pre-scaler = 4 #else _wire->setClock(AGS02MA_I2C_CLOCK); #endif } void AGS02MA::_setI2CHighSpeed() { #if defined (__AVR__) TWSR = 0x00; #endif _wire->setClock(_I2CResetSpeed); } uint16_t AGS02MA::_getDataMSB() { return (_buffer[0] << 8) + _buffer[1]; } uint16_t AGS02MA::_getDataLSB() { return (_buffer[2] << 8) + _buffer[3]; } uint8_t AGS02MA::_CRC8(uint8_t * buf, uint8_t size) { uint8_t crc = 0xFF; // start value for (uint8_t b = 0; b < size; b++) { crc ^= buf[b]; for (uint8_t i = 0; i < 8; i++) { if (crc & 0x80) crc = (crc << 1) ^ 0x31; else crc = (crc << 1); } } return crc; } uint8_t AGS02MA::_bin2bcd (uint8_t value) { return value + 6 * (value / 10); } // -- END OF FILE --