float DS18B20::getTempC() {
sendCommand(MATCH_ROM, CONVERT_T, !selectedPowerMode);
delayForConversion(selectedResolution, selectedPowerMode);
readScratchpad();
uint8_t lsb = selectedScratchpad[TEMP_LSB];
uint8_t msb = selectedScratchpad[TEMP_MSB];
switch (selectedResolution) {
case 9:
lsb &= 0xF8;
break;
case 10:
lsb &= 0xFC;
break;
case 11:
lsb &= 0xFE;
break;
}
uint8_t sign = msb & 0x80;
int16_t temp = (msb << 8) + lsb;
if (sign) {
temp = ((temp ^ 0xffff) + 1) * -1;
}
return temp / 16.0;
}
/** Reads the DS18B20 temperature from scratchpad.
*
* A conversion must have been triggered before using startConversion.
* @param temperature Pointer to a float variable which will hold the temperature
* @return 0 if temperature is valid; -1 if device not ready;
* -2 in case of CRC error
*/
int DS18B20::readTemperature(float* temperature)
{
// make sure that a temperature conversion has been started before
if (false == _conversionStarted)
{
return -1;
}
int result = readScratchpad();
if (0 == result)
{
*temperature = ((int16_t)_scratchpad.tempLow) | ((int16_t)_scratchpad.tempHigh << 8);
if (TemperatureSensor::DS18B20Type == _temperatureSensor)
{
// DS18S20 type has 12 bit resolution (0.0625 Kelvin per LSB)
*temperature *= 0.0625;
}
else if (TemperatureSensor::DS18S20Type == _temperatureSensor)
{
// DS18S20 type has 9 bit resolution (0.5 Kelvin per LSB)
*temperature *= 0.5;
}
else
{
// unknown type
result = -1;
}
}
return result;
}
uint8_t DS18B20::select(uint8_t address[]) {
if (isConnected(address)) {
memcpy(selectedAddress, address, 8);
if (readScratchpad()) {
selectedResolution = getResolution();
sendCommand(MATCH_ROM, READ_POWER_SUPPLY);
selectedPowerMode = oneWire.read_bit();
return 1;
}
}
return 0;
}
uint8_t readTempData_ds18b20(int *temperature) {
if(resetSensor() != 0){
return 1;
}
OWWriteByte(0xCC); //skip rom
OWWriteByte(0x44); //convert T
_delay_ms(800);
if(resetSensor() != 0){
return 1;
}
OWWriteByte(0xCC); //skip rom
OWWriteByte(0xBE); //read scratchpad
*temperature = readScratchpad(2);
//*temperature = 0xFC90;
return 0;
}
