Tasmota/lib/Adafruit_MAX31865-1.1.0-custom/Adafruit_MAX31865.cpp

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2019-10-23 12:11:53 +01:00
/***************************************************
This is a library for the Adafruit PT100/P1000 RTD Sensor w/MAX31865
Designed specifically to work with the Adafruit RTD Sensor
----> https://www.adafruit.com/products/3328
This sensor uses SPI to communicate, 4 pins are required to
interface
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
#include "Adafruit_MAX31865.h"
#ifdef __AVR
#include <avr/pgmspace.h>
#elif defined(ESP8266)
#include <pgmspace.h>
#endif
#include <stdlib.h>
#include <SPI.h>
static SPISettings max31865_spisettings = SPISettings(500000, MSBFIRST, SPI_MODE1);
// Software (bitbang) SPI
Adafruit_MAX31865::Adafruit_MAX31865(int8_t spi_cs, int8_t spi_mosi, int8_t spi_miso, int8_t spi_clk) {
setPins( spi_cs, spi_mosi, spi_miso, spi_clk);
}
void Adafruit_MAX31865::setPins(int8_t spi_cs, int8_t spi_mosi, int8_t spi_miso, int8_t spi_clk) {
_sclk = spi_clk;
_cs = spi_cs;
_miso = spi_miso;
_mosi = spi_mosi;
}
// Hardware SPI init
Adafruit_MAX31865::Adafruit_MAX31865(int8_t spi_cs) {
_cs = spi_cs;
_sclk = _miso = _mosi = -1;
}
// Default constructor
Adafruit_MAX31865::Adafruit_MAX31865(void) {
_cs = _sclk = _miso = _mosi = -1;
}
boolean Adafruit_MAX31865::begin(max31865_numwires_t wires) {
pinMode(_cs, OUTPUT);
digitalWrite(_cs, HIGH);
if (_sclk != -1) {
//define pin modes
pinMode(_sclk, OUTPUT);
digitalWrite(_sclk, LOW);
pinMode(_mosi, OUTPUT);
pinMode(_miso, INPUT);
} else {
//start and configure hardware SPI
SPI.begin();
}
for (uint8_t i=0; i<16; i++) {
// readRegister8(i);
}
setWires(wires);
enableBias(false);
autoConvert(false);
clearFault();
//Serial.print("config: "); Serial.println(readRegister8(MAX31856_CONFIG_REG), HEX);
return true;
}
uint8_t Adafruit_MAX31865::readFault(void) {
return readRegister8(MAX31856_FAULTSTAT_REG);
}
void Adafruit_MAX31865::clearFault(void) {
uint8_t t = readRegister8(MAX31856_CONFIG_REG);
t &= ~0x2C;
t |= MAX31856_CONFIG_FAULTSTAT;
writeRegister8(MAX31856_CONFIG_REG, t);
}
void Adafruit_MAX31865::enableBias(boolean b) {
uint8_t t = readRegister8(MAX31856_CONFIG_REG);
if (b) {
t |= MAX31856_CONFIG_BIAS; // enable bias
} else {
t &= ~MAX31856_CONFIG_BIAS; // disable bias
}
writeRegister8(MAX31856_CONFIG_REG, t);
}
void Adafruit_MAX31865::autoConvert(boolean b) {
uint8_t t = readRegister8(MAX31856_CONFIG_REG);
if (b) {
t |= MAX31856_CONFIG_MODEAUTO; // enable autoconvert
} else {
t &= ~MAX31856_CONFIG_MODEAUTO; // disable autoconvert
}
writeRegister8(MAX31856_CONFIG_REG, t);
}
void Adafruit_MAX31865::setWires(max31865_numwires_t wires ) {
uint8_t t = readRegister8(MAX31856_CONFIG_REG);
if (wires == MAX31865_3WIRE) {
t |= MAX31856_CONFIG_3WIRE;
} else {
// 2 or 4 wire
t &= ~MAX31856_CONFIG_3WIRE;
}
writeRegister8(MAX31856_CONFIG_REG, t);
}
float Adafruit_MAX31865::rtd_to_temperature(uint16_t rtd, float RTDnominal, float refResistor) {
//float Adafruit_MAX31865::temperature(float RTDnominal, float refResistor) {
// http://www.analog.com/media/en/technical-documentation/application-notes/AN709_0.pdf
float Z1, Z2, Z3, Z4, Rt, temp;
Rt = rtd;
Rt /= 32768;
Rt *= refResistor;
// Serial.print("\nResistance: "); Serial.println(Rt, 8);
Z1 = -RTD_A;
Z2 = RTD_A * RTD_A - (4 * RTD_B);
Z3 = (4 * RTD_B) / RTDnominal;
Z4 = 2 * RTD_B;
temp = Z2 + (Z3 * Rt);
temp = (sqrt(temp) + Z1) / Z4;
if (temp >= 0) return temp;
// ugh.
Rt /= RTDnominal;
Rt *= 100; // normalize to 100 ohm
float rpoly = Rt;
temp = -242.02;
temp += 2.2228 * rpoly;
rpoly *= Rt; // square
temp += 2.5859e-3 * rpoly;
rpoly *= Rt; // ^3
temp -= 4.8260e-6 * rpoly;
rpoly *= Rt; // ^4
temp -= 2.8183e-8 * rpoly;
rpoly *= Rt; // ^5
temp += 1.5243e-10 * rpoly;
return temp;
}
float Adafruit_MAX31865::rtd_to_resistance(uint16_t rtd, float refResistor) {
float Rt;
Rt = rtd;
Rt /= 32768;
Rt *= refResistor;
return Rt;
}
float Adafruit_MAX31865::temperature(float RTDnominal, float refResistor) {
uint16_t rtd = readRTD();
return rtd_to_temperature(rtd, RTDnominal, refResistor);
}
uint16_t Adafruit_MAX31865::readRTD (void) {
clearFault();
enableBias(true);
delay(10);
uint8_t t = readRegister8(MAX31856_CONFIG_REG);
t |= MAX31856_CONFIG_1SHOT;
writeRegister8(MAX31856_CONFIG_REG, t);
delay(65);
uint16_t rtd = readRegister16(MAX31856_RTDMSB_REG);
// remove fault
rtd >>= 1;
return rtd;
}
/**********************************************/
uint8_t Adafruit_MAX31865::readRegister8(uint8_t addr) {
uint8_t ret = 0;
readRegisterN(addr, &ret, 1);
return ret;
}
uint16_t Adafruit_MAX31865::readRegister16(uint8_t addr) {
uint8_t buffer[2] = {0, 0};
readRegisterN(addr, buffer, 2);
uint16_t ret = buffer[0];
ret <<= 8;
ret |= buffer[1];
return ret;
}
void Adafruit_MAX31865::readRegisterN(uint8_t addr, uint8_t buffer[], uint8_t n) {
addr &= 0x7F; // make sure top bit is not set
if (_sclk == -1)
SPI.beginTransaction(max31865_spisettings);
else
digitalWrite(_sclk, LOW);
digitalWrite(_cs, LOW);
spixfer(addr);
//Serial.print("$"); Serial.print(addr, HEX); Serial.print(": ");
while (n--) {
buffer[0] = spixfer(0xFF);
//Serial.print(" 0x"); Serial.print(buffer[0], HEX);
buffer++;
}
//Serial.println();
if (_sclk == -1)
SPI.endTransaction();
digitalWrite(_cs, HIGH);
}
void Adafruit_MAX31865::writeRegister8(uint8_t addr, uint8_t data) {
if (_sclk == -1)
SPI.beginTransaction(max31865_spisettings);
else
digitalWrite(_sclk, LOW);
digitalWrite(_cs, LOW);
spixfer(addr | 0x80); // make sure top bit is set
spixfer(data);
//Serial.print("$"); Serial.print(addr, HEX); Serial.print(" = 0x"); Serial.println(data, HEX);
if (_sclk == -1)
SPI.endTransaction();
digitalWrite(_cs, HIGH);
}
uint8_t Adafruit_MAX31865::spixfer(uint8_t x) {
if (_sclk == -1)
return SPI.transfer(x);
// software spi
//Serial.println("Software SPI");
uint8_t reply = 0;
for (int i=7; i>=0; i--) {
reply <<= 1;
digitalWrite(_sclk, HIGH);
digitalWrite(_mosi, x & (1<<i));
digitalWrite(_sclk, LOW);
if (digitalRead(_miso))
reply |= 1;
}
return reply;
}