mirror of
https://github.com/RobTillaart/Arduino.git
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196 lines
3.7 KiB
C++
196 lines
3.7 KiB
C++
//
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// FILE: MAX31850.cpp
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// AUTHOR: Rob Tillaart
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// VERSION: 0.1.4
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// DATE: 2021-06-03
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// PURPOSE: Arduino library for the MAX31850 thermocouple temperature sensor.
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// URL: https://github.com/RobTillaart/MAX31850
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#include "MAX31850.h"
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// OneWire commands
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#define STARTCONVO 0x44
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#define READSCRATCH 0xBE
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#define WRITESCRATCH 0x4E
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// SCRATCHPAD registers
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// bit 1 = reserved bit 0 = error flag
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#define TC_TEMP_LSB 0
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#define TC_TEMP_MSB 1
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// bit 3 = reserved bit 0-2 = error codes
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#define INTERN_TEMP_LSB 2
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#define INTERN_TEMP_MSB 3
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// 4 address bits 0..15
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#define CONFIGURATION 4
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#define RESERVED_1 5
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#define RESERVED_2 6
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#define RESERVED_3 7
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#define SCRATCHPAD_CRC 8
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/////////////////////////////////////////////////////////////////////////////
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//
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// MAX31850
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//
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MAX31850::MAX31850(OneWire* oneWire)
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{
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_oneWire = oneWire;
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_addresFound = false;
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_typeTC = 'K'; // most used.
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_TCTemp = 0;
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_internalTemp = 0;
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_errorBits = 0;
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_failFlag = false;
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_addrBits = 0;
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}
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bool MAX31850::begin(uint8_t retries)
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{
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_addresFound = false;
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for (uint8_t r = retries; (r > 0) && (_addresFound == false); r--)
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{
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_oneWire->reset();
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_oneWire->reset_search();
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_deviceAddress[0] = 0x00;
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_oneWire->search(_deviceAddress);
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_addresFound = _deviceAddress[0] != 0x00 &&
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_oneWire->crc8(_deviceAddress, 7) == _deviceAddress[7];
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}
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return _addresFound;
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}
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bool MAX31850::getAddress(uint8_t* buffer)
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{
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if (_addresFound)
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{
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for (uint8_t i = 0; i < 8; i++)
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{
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buffer[i] = _deviceAddress[i];
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}
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}
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return _addresFound;
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}
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void MAX31850::requestTemperatures(void)
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{
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_oneWire->reset();
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_oneWire->skip();
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_oneWire->write(STARTCONVO, 0);
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}
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bool MAX31850::isConversionComplete(void)
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{
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return (_oneWire->read_bit() == 1);
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}
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float MAX31850::read(void)
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{
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ScratchPad scratchPad;
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for (int i = 0; i < 9; i++) scratchPad[i] = 0;
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// NO CRC CHECK
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readScratchPad(scratchPad, 5);
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_failFlag = scratchPad[TC_TEMP_LSB] & 0x01;
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int16_t rawTemperature = (((int16_t)scratchPad[TC_TEMP_MSB]) << 6) | scratchPad[TC_TEMP_LSB] >> 2;
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_TCTemp = 0.25 * rawTemperature;
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_errorBits = scratchPad[INTERN_TEMP_LSB] & 0x07;
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rawTemperature = (((int16_t)scratchPad[INTERN_TEMP_LSB]) << 4) | scratchPad[INTERN_TEMP_LSB] >> 4;
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_internalTemp = 0.0625 * rawTemperature;
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_addrBits = scratchPad[CONFIGURATION] & 0x0F;
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return _TCTemp;
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}
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float MAX31850::getTempTC(void)
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{
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return _TCTemp;
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}
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float MAX31850::getTempInternal(void)
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{
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return _internalTemp;
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}
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uint8_t MAX31850::getErrorCode()
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{
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return _errorBits;
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}
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uint8_t MAX31850::getAddressPins()
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{
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return _addrBits;
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};
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bool MAX31850::setTypeTC(char typeTC)
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{
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switch(toupper(typeTC))
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{
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case 'E':
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case 'J':
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case 'K':
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case 'N':
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case 'R':
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case 'S':
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case 'T':
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_typeTC = toupper(typeTC);
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return true;
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}
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return false;
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}
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char MAX31850::getTypeTC()
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{
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return _typeTC;
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}
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/////////////////////////////////////////////////////////////////////////////
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//
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// PROTECTED
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//
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void MAX31850::readScratchPad(uint8_t *scratchPad, uint8_t fields)
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{
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_oneWire->reset();
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_oneWire->select(_deviceAddress);
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_oneWire->write(READSCRATCH);
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for (uint8_t i = 0; i < fields; i++)
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{
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scratchPad[i] = _oneWire->read();
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}
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_oneWire->reset();
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}
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/////////////////////////////////////////////////////////////////////////////
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//
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// MAX31851
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//
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MAX31851::MAX31851(OneWire * onewire) : MAX31850(onewire)
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{
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}
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// -- END OF FILE --
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