148 lines
3.8 KiB
C++
148 lines
3.8 KiB
C++
#include "MAX31855.h"
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#if defined (__AVR_ATmega640__) \
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|| defined (__AVR_ATmega1280__) \
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|| defined (__AVR_ATmega1281__) \
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|| defined (__AVR_ATmega2560__) \
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|| defined (__AVR_ATmega2561__)
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// Arduino Mega
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#define DATAIN 50//MISO
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#define DATAOUT 51//MOSI
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#define SPICLOCK 52//sck
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#define SS 53
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#elif defined (__AVR_ATmega168__) \
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|| defined (__AVR_ATmega168P__) \
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|| defined (__AVR_ATmega88P__) \
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|| defined (__AVR_ATmega88__) \
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|| defined (__AVR_ATmega48P__) \
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|| defined (__AVR_ATmega48__) \
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|| defined (__AVR_ATmega328P__)
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#define DATAIN 12//MISO
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#define DATAOUT 11//MOSI
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#define SPICLOCK 13//sck
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#define SS 10
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#endif
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byte clr;
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MAX31855::MAX31855(uint8_t csPin, uint32_t updateIntervalMs){
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this->status.csPin = csPin;
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this->status.stat = 0;
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this->status.temperature = 0.0;
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this->updateIntervalMs = updateIntervalMs;
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this->lastUpdate = 0;
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for(uint8_t i = 0; i< NUMTCAVGSAMPLES; i++){
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readings[i] = 0;
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}
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counter = 0;
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}
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void MAX31855::setup(){
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if(!setupDone){
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setupDone = true;
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pinMode(DATAOUT, OUTPUT);
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pinMode(SPICLOCK,OUTPUT);
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pinMode(DATAIN, INPUT);
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//pinMode(10,OUTPUT);
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digitalWrite(SS,HIGH); // set the pull up on the SS pin (SPI doesn't work otherwise!!)
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clr = 0;
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//The SPI control register (SPCR) has 8 bits, each of which control a particular SPI setting.
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// SPCR
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// | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |0000000000000000000
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// | SPIE | SPE | DORD | MSTR | CPOL | CPHA | SPR1 | SPR0 |
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// SPIE - Enables the SPI interrupt when 1
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// SPE - Enables the SPI when 1
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// DORD - Sends data least Significant Bit First when 1, most Significant Bit first when 0
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// MSTR - Sets the Arduino in master mode when 1, slave mode when 0
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// CPOL - Sets the data clock to be idle when high if set to 1, idle when low if set to 0
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// CPHA - Samples data on the falling edge of the data clock when 1, rising edge when 0'
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// SPR1 and SPR0 - Sets the SPI speed, 00 is fastest (4MHz) 11 is slowest (250KHz)
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SPCR = (1<<SPE)|(1<<MSTR)|(1<<CPHA);// SPI enable bit set, master, data valid on falling edge of clock
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clr=SPSR;
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clr=SPDR;
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//Serial.println("setup done");
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}
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pinMode(status.csPin, OUTPUT);
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digitalWrite(status.csPin, HIGH);
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// take one reading and fill the array
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readThermocouple(&status);
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for(uint8_t i = 0; i< NUMTCAVGSAMPLES; i++){
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readings[i] = status.temperature;
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}
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}
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char MAX31855::spi_transfer(volatile char data)
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{
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SPDR = data; // Start the transmission
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while (!(SPSR & (1 << SPIF))) // Wait the end of the transmission
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{
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};
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return SPDR; // return the received byte
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}
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void MAX31855::readThermocouple(struct max31855Status* input) {
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digitalWrite(input->csPin, LOW);
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uint32_t result = 0x0000;
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byte reply = 0;
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char data = 0; // dummy data to write
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for (int i = 0; i < 4; i++) { // read the 32 data bits from the MAX31855
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reply = spi_transfer(data);
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result = result << 8;
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result |= reply;
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}
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//Serial.print("Read result is: ");
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//Serial.print(result, BIN);
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result >>= 18;
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uint16_t value = 0xFFF & result; // mask off the sign bit and shit to the correct alignment for the temp data
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input->stat = reply & B111;
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input->temperature = value * 0.25;
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digitalWrite(input->csPin, HIGH);
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}
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void MAX31855::update(){
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if(millis() - lastUpdate >= updateIntervalMs){
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lastUpdate = millis();
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readThermocouple(&status);
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//remove this after testing! haha
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//status.temperature = random(25, 30);
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//status.stat = 0;
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readings[counter] = status.temperature;
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counter++;
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if(counter>=NUMTCAVGSAMPLES){
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counter = 0;
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}
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double total = 0;
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for(uint8_t i = 0; i< NUMTCAVGSAMPLES; i++){
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total += readings[i];
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}
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temperature = total / NUMTCAVGSAMPLES;
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}
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}
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