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@budulinek
budulinek committed Nov 4, 2023
1 parent 0fb7ff9 commit de590b0
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Showing 7 changed files with 259 additions and 140 deletions.
178 changes: 101 additions & 77 deletions MAX31865_NonBlocking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -25,28 +25,18 @@

#include <stdlib.h>

void MAX31865::begin(RtdWire wires, FilterFreq filter) {
void MAX31865::begin(RtdWire wires, FilterFreq filter, ConvMode mode) {
_spi->begin();
pinMode(_cs, OUTPUT);

setThresholds(0, 0xFFFF);
clearFault();
setConfig(0x00);

setBias(true);
setWires(wires);
setFilter(filter);


// Serial.print("config: ");
// Serial.println(readRegister8(CONFIG_ADDR), HEX);
}

void MAX31865::setConfig(uint8_t cfg_reg) {
writeRegister8(CONFIG_ADDR, cfg_reg);
}

uint8_t MAX31865::getConfig() {
return readRegister8(CONFIG_ADDR);
setConvMode(mode);
}

void MAX31865::setWires(RtdWire wires) {
Expand All @@ -60,13 +50,13 @@ void MAX31865::setWires(RtdWire wires) {
setConfig(t);
}

MAX31865::RtdWire MAX31865::getWires(void) {
return (MAX31865::RtdWire(getConfig() & CONFIG_3WIRE_RTD_BIT));
MAX31865::RtdWire MAX31865::getWires() {
return MAX31865::RtdWire((getConfig() & CONFIG_3WIRE_RTD_BIT) == true);
}

void MAX31865::setFilter(const FilterFreq filter) {
uint8_t t = getConfig();
if (t & CONFIG_CONVERSION_MODE_BIT) return;
if (t & CONFIG_CONVERSION_MODE_BIT) return; // Do not change the notch frequency while in continuous conversion mode.
if (filter == FILTER_50HZ) {
t |= CONFIG_FILTER_BIT;
} else {
Expand All @@ -75,45 +65,72 @@ void MAX31865::setFilter(const FilterFreq filter) {
setConfig(t);
}

MAX31865::FilterFreq MAX31865::getFilter(void) {
return (MAX31865::FilterFreq(getConfig() & CONFIG_FILTER_BIT));
MAX31865::FilterFreq MAX31865::getFilter() {
return MAX31865::FilterFreq((getConfig() & CONFIG_FILTER_BIT) == true);
}

void MAX31865::autoConvert(bool b) {
_autoConvert = b;
void MAX31865::setConvMode(ConvMode mode) {
uint8_t t = getConfig();
if (b) {
if (mode == CONV_MODE_CONTINUOUS) {
t |= CONFIG_CONVERSION_MODE_BIT; // enable continuous conversion
} else {
t &= ~CONFIG_CONVERSION_MODE_BIT; // disable continuous conversion
}
setConfig(t);
}

bool MAX31865::isConversionComplete(void) {
if (_autoConvert == true) return true;
MAX31865::ConvMode MAX31865::getConvMode() {
return MAX31865::ConvMode((getConfig() & CONFIG_CONVERSION_MODE_BIT) == true);
}

void MAX31865::setBias(bool b) {
uint8_t t = getConfig();
if (b) {
t |= CONFIG_VBIAS_BIT; // enable bias
} else {
t &= ~CONFIG_VBIAS_BIT; // disable bias
}
setConfig(t);
}

bool MAX31865::getBias() {
return getConfig() & CONFIG_VBIAS_BIT;
}

void MAX31865::setConfig(uint8_t cfg_reg) {
writeRegister8(CONFIG_ADDR, cfg_reg);
}

uint8_t MAX31865::getConfig() {
return readRegister8(CONFIG_ADDR);
}

bool MAX31865::isConversionComplete() {
if (getConvMode() == MAX31865::CONV_MODE_CONTINUOUS) return true;
switch (_state) {
case 0:
{
// clear FAULTSTAT register
clearFault();
uint8_t t = getConfig();
t |= CONFIG_VBIAS_BIT; // enable bias
setConfig(t);
// enable bias
setBias(true);
_chrono = millis();
_state++;
}
break;
case 1:
{
if ((uint32_t)(millis() - _chrono) > TIMEOUT_VBIAS) {
setFaultCycle(MAX31865::FAULT_AUTO);
// run fault detection cycle with automatic delay
setFaultCycle(MAX31865::FAULT_AUTO_RUN);
_state++;
}
}
break;
case 2:
{
if (getFaultCycle() == MAX31865::FAULT_STATUS_FINISHED) {
// trigger single shot conversion
uint8_t t = getConfig();
t |= CONFIG_1SHOT_BIT;
setConfig(t);
Expand All @@ -126,20 +143,14 @@ bool MAX31865::isConversionComplete(void) {
// The CONFIG_1SHOT_BIT is a self-clearing bit. But it clears to 0 only
// when a new conversion result is available in the RTD Data Registers.
if ((getConfig() & CONFIG_1SHOT_BIT) == false) {
_rtd = readRegister16(RTD_MSB_ADDR);
_state++;
// disable bias
setBias(false);
// conversion is finished, reset the state and return true
_state = 0;
return true;
}
}
break;
case 4:
{
uint8_t t = getConfig();
t &= ~CONFIG_VBIAS_BIT; // disable bias
setConfig(t);
_state = 0;
return true;
}
break;
default:
break;
}
Expand All @@ -153,47 +164,44 @@ void MAX31865::setThresholds(uint16_t lower, uint16_t upper) {
writeRegister8(HIGH_FAULT_THRESH_MSB_ADDR, upper >> 8);
}

uint16_t MAX31865::getLowerThreshold(void) {
uint16_t MAX31865::getLowerThreshold() {
return readRegister16(LOW_FAULT_THRESH_MSB_ADDR);
}

uint16_t MAX31865::getUpperThreshold(void) {
uint16_t MAX31865::getUpperThreshold() {
return readRegister16(HIGH_FAULT_THRESH_MSB_ADDR);
}

void MAX31865::setFaultCycle(FaultCycle fault_cycle) {
if (fault_cycle) {
uint8_t cfg_reg = getConfig();
cfg_reg &= 0x11; // mask out wire and filter bits
switch (fault_cycle) {
case FAULT_AUTO:
setConfig(cfg_reg | 0b10000100);
break;
case FAULT_MANUAL_RUN:
setConfig(cfg_reg | 0b10001000);
break;
case FAULT_MANUAL_FINISH:
setConfig(cfg_reg | 0b10001100);
break;
case FAULT_NONE:
default:
break;
}
uint8_t cfg_reg = getConfig();
cfg_reg &= 0x11; // mask out wire and filter bits
switch (fault_cycle) {
case FAULT_AUTO_RUN:
setConfig(cfg_reg | 0b10000100);
break;
case FAULT_MANUAL_RUN:
setConfig(cfg_reg | 0b10001000);
break;
case FAULT_MANUAL_FINISH:
setConfig(cfg_reg | 0b10001100);
break;
default:
break;
}
}

MAX31865::FaultCycleStatus MAX31865::getFaultCycle(void) {
MAX31865::FaultCycleStatus MAX31865::getFaultCycle() {
uint8_t t = getConfig();
t &= CONFIG_FAULT_CYCLE_MASK;
t >>= 2;
return MAX31865::FaultCycleStatus(t);
}

uint8_t MAX31865::getFault(void) {
uint8_t MAX31865::getFault() {
return readRegister8(FAULT_STATUS_ADDR);
}

void MAX31865::clearFault(void) {
void MAX31865::clearFault() {
uint8_t t = getConfig();
t &= ~CONFIG_1SHOT_BIT; // Write a 0
t &= ~CONFIG_FAULT_CYCLE_MASK; // Write a 0
Expand All @@ -202,38 +210,54 @@ void MAX31865::clearFault(void) {
}

float MAX31865::getResistance(uint16_t rReference) {
uint16_t rtdRaw;
if (_autoConvert == true) {
_rtd = readRegister16(RTD_MSB_ADDR);
}
rtdRaw = _rtd;
uint16_t rtdRaw = readRegister16(RTD_MSB_ADDR);

// Remove fault bit. This bit is set to 1 if there is an error in FAULTSTAT,
// so it does not provide any additional information.
// Use getFault() to read FAULTSTAT.
// Use getFault() to read the FAULTSTAT register.
rtdRaw >>= 1;

return static_cast<float>(rReference) * static_cast<float>(rtdRaw) / RTD_MAX_VAL;
}

float MAX31865::getTemperature(uint16_t rNominal, uint16_t rReference) {
float MAX31865::getTemperature(uint16_t rNominal, uint16_t rReference, MAX31865::CalcMethod method) {

float Z1, Z2, Z3, Z4, Rt, temp;

Rt = getResistance(rReference);

if (method == MAX31865::CALC_LINEAR) {
Rt /= static_cast<float>(rNominal);
Rt *= 100.0f;
return 2.57559f * Rt - 257.339f; // optimal coeficient values for -40°C to +85°C
}

Z1 = -RTD_A;
Z2 = RTD_A * RTD_A - (4 * RTD_B);
Z3 = (4 * RTD_B) / static_cast<float>(rNominal);
Z4 = 2 * RTD_B;

Rt = getResistance(rReference);

/* Convert resistance to temperature */
temp = (Z1 + sqrtf(Z2 + (Z3 * Rt))) / Z4;
// if (temp < -12.5f) {
// Rt /= static_cast<float>(rNominal);
// Rt *= 100.0f;
// temp = -242.97f + 2.2838f * Rt + 1.4727e-3f * Rt * Rt;
// }

if (method == MAX31865::CALC_POLY_ADVANCED) {
if (temp < 0) {
Rt /= static_cast<float>(rNominal);
Rt *= 100.0f;
float rpoly = Rt;
temp = -242.02f;
temp += 2.2228f * rpoly;
rpoly *= Rt; // square
temp += 2.5859e-3f * rpoly;
rpoly *= Rt; // ^3
temp -= 4.8260e-6f * rpoly;
rpoly *= Rt; // ^4
temp -= 2.8183e-8f * rpoly;
rpoly *= Rt; // ^5
temp += 1.5243e-10f * rpoly;

// temp = -242.97f
// + 2.2838f * Rt
// + 1.4727e-3f * Rt * Rt;
}
}

return temp;
}
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