Library for the MAX31856 Precision Thermocouple to Digital Converter with Linearization
Dependents: MAX31856_example_program
Fork of MAX31856 by
Diff: MAX31856.cpp
- Revision:
- 0:b714c6a7c969
- Child:
- 1:a1bbb5c254f2
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MAX31856.cpp Thu Sep 14 17:56:47 2017 +0000 @@ -0,0 +1,616 @@ +#include <mbed.h> +#include "MAX31856.h" + +#define LOG(args...) printf(args) + +//***************************************************************************** +MAX31856::MAX31856(SPI& _spi, PinName _ncs, uint8_t _type, uint8_t _fltr, uint8_t _samples, uint8_t _conversion_mode) : spi(_spi), ncs(_ncs), samples(_samples) { + spi.format(8,3); //configure the correct SPI mode to beable to program the registers intially correctly + setThermocoupleType(_type); + setEmiFilterFreq(_fltr); + setNumSamplesAvg(_samples); + setConversionMode(_conversion_mode); +} + + +//***************************************************************************** +float MAX31856::readTC() +{ + //Check and see if the MAX31856 is set to conversion mode ALWAYS ON + if (conversion_mode==0) { //means that the conversion mode is normally off + setOneShotMode(CR0_1_SHOT_MODE_ONE_CONVERSION); // turn on the one shot mode for singular conversion + thermocouple_conversion_count=0; //reset the conversion count back to zero to make sure minimum conversion time reflects one shot mode requirements + } + + //calculate minimum wait time for conversions + calculateDelayTime(); + + //initialize other info for the read functionality + int32_t temp; + uint8_t buf_read[3], buf_write[3]={ADDRESS_LTCBH_READ,ADDRESS_LTCBM_READ,ADDRESS_LTCBL_READ}; + + bool read_thermocouple_temp=checkFaultsThermocoupleConnection(); //check and see if there are any faults that prohibit a normal read of the register + + if(read_thermocouple_temp){ //no faults with connection are present so continue on with normal read of temperature + uint32_t time = us_ticker_read(); + uint32_t duration = time - lastReadTime; + if (duration > conversion_time) { // more than current conversion time + for(int i=0; i<3; i++) { + spiEnable(); + buf_read[i]=spi.write(buf_write[i]); + buf_read[i]=spi.write(buf_write[i]); + spiDisable(); + } + + //Convert the registers contents into the correct value + temp =((buf_read[0] & 0xFF) << 11); //Shift Byte 2 into place + temp|=((buf_read[1] & 0xFF) << 3); //Shift Byte 1 into place + temp|=((buf_read[2] & 0xFF) >> 5); //Shift Byte 0 into place + float val=(temp/128.0f); //Divide the binary string by 2 to the 7th power + return val; + } + } + thermocouple_conversion_count++; //iterate the conversion count to speed up time in between future converions in always on mode + + checkFaultsThermocoupleThresholds(); //print any faults to the terminal + return 0; +} + + +//***************************************************************************** +float MAX31856::readCJ() +{ + int32_t temp; + uint8_t buf_read[3], buf_write=ADDRESS_CJTH_READ; + + spiEnable(); + for(int i=0; i<3; i++) + { + buf_read[i]=spi.write(buf_write); + } + spiDisable(); + + //Convert the registers contents into the correct value + temp =((int32_t)(buf_read[1] << 6)); //Shift the MSB into place + temp|=((int32_t)(buf_read[2] >> 2)); //Shift the LSB into place + float val=((float)(temp/64.0)); //Divide the binary string by 2 to the 6th power + + checkFaultsColdJunctionThresholds(); //print any faults to the terminal + + return val; +} + +//***************************************************************************** +uint8_t MAX31856::checkFaultsThermocoupleThresholds() +{ + uint8_t fault_byte=registerReadByte(ADDRESS_SR_READ); //Read contents of fault status register + uint8_t temp[2], return_int; + for(int i=0; i<2; i++) + temp[i]=fault_byte; + + //Check if any of the faults for thermocouple connection are triggered + if ((fault_byte&0x4C)==0) //means no fault is detected for thermocouple thresholds + return_int=0; + else { + if ((fault_byte&0x40)==0) { //check if normal operation of thermocouple is true + if (temp[0]&0x08) { + LOG("FAULT! Thermocouple temp is higher than the threshold that is set!\r\n"); + return_int=1; + } + else if (temp[1]&0x04) { + LOG("FAULT! Thermocouple temp is lower than the threshold that is set!\r\n"); + return_int=2; + } + } + else { //Thermocouples is operating outside of normal range + LOG("FAULT! Thermocouple temperature is out of range for specific type of thermocouple!\r\n"); + if (temp[0]&0x08) { + LOG("FAULT! Thermocouple temp is higher than the threshold that is set!\r\n"); + return_int=4; + } + else if (temp[1]&0x04) { + LOG("FAULT! Thermocouple temp is lower than the threshold that is set!\r\n"); + return_int=5; + } + else //no other faults are flagged besides unnatural operation + return_int=3; + } + } + return return_int; +} + +//***************************************************************************** +uint8_t MAX31856::checkFaultsColdJunctionThresholds() +{ + uint8_t fault_byte=registerReadByte(ADDRESS_SR_READ); //Read contents of fault status register + uint8_t temp[2], return_int; + for(int i=0; i<2; i++) + temp[i]=fault_byte; + + //Check if any of the faults for thermocouple connection are triggered + if ((fault_byte&0xB0)==0) //means no fault is detected for cold junction thresholds + return_int=0; + else { + if ((fault_byte&0x80)==0) { //check if normal operation of cold junction is true + if (temp[0]&0x20) { + LOG("FAULT! Cold Junction temp is higher than the threshold that is set!\r\n"); + return_int=1; + } + else if (temp[1]&0x10) { + LOG("FAULT! Cold Junction temp is lower than the threshold that is set!\r\n"); + return_int=2; + } + } + else { //Cold Junction is operating outside of normal range + LOG("FAULT! Cold Junction temperature is out of range for specific type of thermocouple!\r\n"); + if (temp[0]&0x20) { + LOG("FAULT! Cold Junction temp is higher than the threshold that is set!\r\n"); + return_int=4; + } + else if (temp[1]&0x10) { + LOG("FAULT! Cold Junction temp is lower than the threshold that is set!\r\n"); + return_int=5; + } + else //no other faults are flagged besides unnatural operation + return_int=3; + } + } + return return_int; +} + +//***************************************************************************** +bool MAX31856::checkFaultsThermocoupleConnection() +{ + uint8_t fault_byte=registerReadByte(ADDRESS_SR_READ); //Read contents of fault status register + uint8_t temp[2]; + for(int i=0; i<2; i++) + temp[i]=fault_byte; + + //Check if any of the faults for thermocouple connection are triggered + if (fault_byte==0) //means no fault is detected + return_val=1; + else{ + if (temp[0]&0x02) { + LOG("Overvotage/Undervoltage Fault triggered! Input voltage is negative or the voltage is greater than Vdd! Please check thermocouple connection!\r\n"); + return_val=0; + } + if (temp[1]&0x01) { + LOG("Open circuit fault detected! Please check thermocouple connection!\r\n"); + return_val=0; + } + } + return return_val; +} + + +//Register:CR0 Bits: 7 +//***************************************************************************** +bool MAX31856::setConversionMode(uint8_t val) +{ + if (val==CR0_CONV_MODE_NORMALLY_OFF) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_7, val); + conversion_mode=0; + LOG("Register containing\t\tsetConversionMode\t\twas programmed with the parameter\t\tCR0_CONV_MODE_NORMALLY_OFF\r\n"); + } + else if (val==CR0_CONV_MODE_NORMALLY_ON) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_7, val); + conversion_mode=1; + LOG("Register containing\t\tsetConversionMode\t\twas programmed with the parameter\t\tCR0_CONV_MODE_NORMALLY_ON\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 0 (CR0) bit 7. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR0 Bits: 6 +//***************************************************************************** +bool MAX31856::setOneShotMode(uint8_t val) +{ + if (val==CR0_1_SHOT_MODE_NO_CONVERSION) + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_6, val); + else if (val==CR0_1_SHOT_MODE_ONE_CONVERSION) + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_6, val); + else { + LOG("Incorrect parameter selected for Control Register 0 (CR0) bit 6. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR0 Bits: 5:4 +//***************************************************************************** +bool MAX31856::setOpenCircuitFaultDetection(uint8_t val) +{ + if (val==CR0_OC_DETECT_DISABLED) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_5_4, val); + LOG("Register containing\t\tsetOpenCircuitFaultDetection\t\twas programmed with the parameter\t\tCR0_OC_DETECT_DISABLED\r\n"); + } + else if (val==CR0_OC_DETECT_ENABLED_R_LESS_5k) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_5_4, val); + LOG("Register containing\t\tsetOpenCircuitFaultDetection\t\twas programmed with the parameter\t\tCR0_OC_DETECT_ENABLED_R_LESS_5k\r\n"); + } + else if (val==CR0_OC_DETECT_ENABLED_TC_LESS_2ms) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_5_4, val); + LOG("Register containing\t\tsetOpenCircuitFaultDetection\t\twas programmed with the parameter\t\tCR0_OC_DETECT_ENABLED_TC_LESS_2ms\r\n"); + } + else if (val==CR0_OC_DETECT_ENABLED_TC_MORE_2ms) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_5_4, val); + LOG("Register containing\t\tsetOpenCircuitFaultDetection\t\twas programmed with the parameter\t\tCR0_OC_DETECT_ENABLED_TC_MORE_2ms\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 0 (CR0) bits 5:4. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR0 Bits: 3 +//***************************************************************************** +bool MAX31856::setColdJunctionDisable(uint8_t val) +{ + if (val==CR0_COLD_JUNC_ENABLE) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_3, val); + cold_junction_enabled=1; + LOG("Register containing\t\tsetColdJunctionDisable\t\twas programmed with the parameter\t\tCR0_COLD_JUNC_ENABLE\r\n"); + } + else if (val==CR0_COLD_JUNC_DISABLE) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_3, val); + cold_junction_enabled=0; + LOG("Register containing\t\tsetColdJunctionDisable\t\twas programmed with the parameter\t\tCR0_COLD_JUNC_DISABLE\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 0 (CR0) bit 3. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR0 Bits: 2 +//***************************************************************************** +bool MAX31856::setFaultMode(uint8_t val) +{ + if (val==CR0_FAULT_MODE_COMPARATOR) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_2, val); + LOG("Register containing\t\tsetFaultMode\t\twas programmed with the parameter\t\tCR0_FAULT_MODE_COMPARATOR\r\n"); + } + else if (val==CR0_FAULT_MODE_INTERUPT) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_2, val); + LOG("Register containing\t\tsetFaultMode\t\twas programmed with the parameter\t\tCR0_FAULT_MODE_INTERUPT\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 0 (CR0) bit 2. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR0 Bits: 1 +//***************************************************************************** +bool MAX31856::setFaultStatusClear(uint8_t val) +{ + if (val==CR0_FAULTCLR_DEFAULT_VAL) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_1, val); + LOG("Register containing\t\tsetFaultStatusClear\t\twas programmed with the parameter\t\tCR0_FAULTCLR_DEFAULT_VAL\r\n"); + } + else if (val==CR0_FAULTCLR_RETURN_FAULTS_TO_ZERO) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_1, val); + LOG("Register containing\t\tsetFaultStatusClear\t\twas programmed with the parameter\t\tCR0_FAULTCLR_RETURN_FAULTS_TO_ZERO\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 0 (CR0) bit 1. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR0 Bits: 0 +//***************************************************************************** +bool MAX31856::setEmiFilterFreq(uint8_t val) +{ + if (val==CR0_FILTER_OUT_60Hz) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_0, val); + filter_mode=0; + LOG("Register containing\t\tsetEmiFilterFreq\t\twas programmed with the parameter\t\tCR0_FILTER_OUT_60Hz\r\n"); + } + else if (val==CR0_FILTER_OUT_50Hz) { + return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_0, val); + filter_mode=1; + LOG("Register containing\t\tsetEmiFilterFreq\t\twas programmed with the parameter\t\tCR0_FILTER_OUT_50Hz\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 0 (CR0) bit 0. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR1 Bits: 6:4 +//***************************************************************************** +bool MAX31856::setNumSamplesAvg(uint8_t val) +{ + if (val==CR1_AVG_TC_SAMPLES_1) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_6_4, val); + samples=1; + LOG("Register containing\t\tsetNumSamplesAvg\t\twas programmed with the parameter\t\tCR1_AVG_TC_SAMPLES_1\r\n"); + } + else if (val==CR1_AVG_TC_SAMPLES_2) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_6_4, val); + samples=2; + LOG("Register containing\t\tsetNumSamplesAvg\t\twas programmed with the parameter\t\tCR1_AVG_TC_SAMPLES_2\r\n"); + } + else if (val==CR1_AVG_TC_SAMPLES_4) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_6_4, val); + samples=4; + LOG("Register containing\t\tsetNumSamplesAvg\t\twas programmed with the parameter\t\tCR1_AVG_TC_SAMPLES_4\r\n"); + } + else if (val==CR1_AVG_TC_SAMPLES_8) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_6_4, val); + samples=8; + LOG("Register containing\t\tsetNumSamplesAvg\t\twas programmed with the parameter\t\tCR1_AVG_TC_SAMPLES_8\r\n"); + } + else if (val==CR1_AVG_TC_SAMPLES_16) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_6_4, val); + samples=16; + LOG("Register containing\t\tsetNumSamplesAvg\t\twas programmed with the parameter\t\tCR1_AVG_TC_SAMPLES_16\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 1 (CR1) bits 6:4. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:CR1 Bits: 3:0 +//***************************************************************************** +bool MAX31856::setThermocoupleType(uint8_t val) +{ + if (val==CR1_TC_TYPE_B) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_B\r\n"); + } + else if (val==CR1_TC_TYPE_E) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_E\r\n"); + } + else if (val==CR1_TC_TYPE_J) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_J\r\n"); + } + else if (val==CR1_TC_TYPE_K) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_K\r\n"); + } + else if (val==CR1_TC_TYPE_N) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_N\r\n"); + } + else if (val==CR1_TC_TYPE_R) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_R\r\n"); + } + else if (val==CR1_TC_TYPE_S) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_S\r\n"); + } + else if (val==CR1_TC_TYPE_T) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=false; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_T\r\n"); + } + else if (val==CR1_TC_TYPE_VOLT_MODE_GAIN_8) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=true; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_VOLT_MODE_GAIN_8\r\n"); + } + else if (val==CR1_TC_TYPE_VOLT_MODE_GAIN_32) { + return_val=registerReadWriteByte(ADDRESS_CR1_READ, ADDRESS_CR1_WRITE, CR1_CLEAR_BITS_3_0, val); + voltage_mode=true; + LOG("Register containing\t\tsetThermocoupleType\t\twas programmed with the parameter\t\tCR1_TC_TYPE_VOLT_MODE_GAIN_32\r\n"); + } + else { + LOG("Incorrect parameter selected for Control Register 1 (CR1) bits 3:0. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:MASK Bits: 5:0 +//***************************************************************************** +bool MAX31856::setFaultMasks(uint8_t val, bool enable) +{ + if(enable) + val=0; + if (val==MASK_CJ_FAULT_THRESHOLD_HIGH) { //Cold Junction High Threshold Fault Mask + return_val=registerReadWriteByte(ADDRESS_MASK_READ, ADDRESS_MASK_WRITE, MASK_CLEAR_BITS_5, val); + LOG("Register containing\t\tsetFaultMasks\t\twas programmed with the parameter\t\tMASK_CJ_FAULT_THRESHOLD_HIGH\r\n"); + } + else if (val==MASK_CJ_FAULT_THRESHOLD_LOW) { //Cold Junction Low Threshold Fault Mask + return_val=registerReadWriteByte(ADDRESS_MASK_READ, ADDRESS_MASK_WRITE, MASK_CLEAR_BITS_4, val); + LOG("Register containing\t\tsetFaultMasks\t\twas programmed with the parameter\t\tMASK_CJ_FAULT_THRESHOLD_LOW\r\n"); + } + else if (val==MASK_TC_FAULT_THRESHOLD_HIGH) { //Thermocouple High Threshold Fault Mask + return_val=registerReadWriteByte(ADDRESS_MASK_READ, ADDRESS_MASK_WRITE, MASK_CLEAR_BITS_3, val); + LOG("Register containing\t\tsetFaultMasks\t\twas programmed with the parameter\t\tMASK_TC_FAULT_THRESHOLD_HIGH\r\n"); + } + else if (val==MASK_TC_FAULT_THRESHOLD_LOW) { //Thermocouple Low Threshold Fault Mask + return_val=registerReadWriteByte(ADDRESS_MASK_READ, ADDRESS_MASK_WRITE, MASK_CLEAR_BITS_2, val); + LOG("Register containing\t\tsetFaultMasks\t\twas programmed with the parameter\t\tMASK_TC_FAULT_THRESHOLD_LOW\r\n"); + } + else if (val==MASK_OVER_UNDER_VOLT_FAULT) { //Over-Voltage/Under-Voltage Input Fault Mask + return_val=registerReadWriteByte(ADDRESS_MASK_READ, ADDRESS_MASK_WRITE, MASK_CLEAR_BITS_1, val); + LOG("Register containing\t\tsetFaultMasks\t\twas programmed with the parameter\t\tMASK_OVER_UNDER_VOLT_FAULT\r\n"); + } + else if (val==MASK_OPEN_CIRCUIT_FAULT) { //Thermocouple Open-Circuit Fault Mask + return_val=registerReadWriteByte(ADDRESS_MASK_READ, ADDRESS_MASK_WRITE, MASK_CLEAR_BITS_0, val); + LOG("Register containing\t\tsetFaultMasks\t\twas programmed with the parameter\t\tMASK_OPEN_CIRCUIT_FAULT\r\n"); + } + else { + LOG("Incorrect parameter selected for Mask Register bits 5:0. Default value not changed.\r\nPlease see MAX31856.h for list of valid parameters. \r\n"); + return_val=0; //returns a 0 to flag that the parameter wasn't programmed due to wrong parameter in function call + } + return return_val; +} + + +//Register:MASK Bits: 5:0 +//****************************************************************************** +bool MAX31856::setFaultThresholds(uint8_t val, float temperature) +{ + if (val==MASK_CJ_FAULT_THRESHOLD_HIGH) { //Cold Junction High Threshold Fault Mask + int8_t temperature_byte=temperature; + return_val=registerWriteByte(ADDRESS_CJHF_WRITE, temperature_byte); + } + else if (val==MASK_CJ_FAULT_THRESHOLD_LOW) { //Cold Junction Low Threshold Fault Mask + int8_t temperature_byte=temperature; + return_val=registerWriteByte(ADDRESS_CJLF_WRITE, temperature_byte); + } + else if (val==MASK_TC_FAULT_THRESHOLD_HIGH) { //Thermocouple High Threshold Fault Mask + int8_t temperature_byte[2]; + int16_t temperature_multi_byte =temperature*4.0; + //now split up the 16bit int into two bytes to program the registers with + temperature_byte[0]=((uint8_t)((temperature_multi_byte)&(0xFF00) >> 8)); + temperature_byte[1]=((uint8_t)((temperature_multi_byte)&(0x00FF))); + + return_val=registerWriteByte(ADDRESS_LTHFTH_WRITE, temperature_byte[0]); + return_val=registerWriteByte(ADDRESS_LTHFTL_WRITE, temperature_byte[1]); + } + else if (val==MASK_TC_FAULT_THRESHOLD_LOW) { //Thermocouple LOW Threshold Fault Mask + int8_t temperature_byte[2]; + int16_t temperature_multi_byte =temperature*4.0; + //now split up the 16bit int into two bytes to program the registers with + temperature_byte[0]=((uint8_t)((temperature_multi_byte)&(0xFF00) >> 8)); + temperature_byte[1]=((uint8_t)((temperature_multi_byte)&(0x00FF))); + + return_val=registerWriteByte(ADDRESS_LTHFTH_WRITE, temperature_byte[0]); + return_val=registerWriteByte(ADDRESS_LTHFTL_WRITE, temperature_byte[1]); + } + else + LOG("Please select correct threshold register to program with the correct value!\r\n"); + return return_val; +} + +//****************************************************************************** +bool MAX31856::coldJunctionOffset(float temperature) +{ + if (temperature > 7.9375 || temperature < -8.0) { + LOG("Input value to offest the cold junction point is non valid. enter in value in range -8 to +7.9375\r\n"); + return_val = 0; + } + int8_t temp_val=temperature*16.0f; //normalize the value to get rid of decimal and shorten it to size of register + return_val=registerWriteByte(ADDRESS_CJTO_WRITE, temp_val); //write the byte to cold junction offset register + return return_val; +} + + +//The following functions are for internal library use only +//****************************************************************************** +void MAX31856::spiEnable() +{ + ncs=0; //Set CS low to start transmission (interrupts conversion) + return; +} + + +//****************************************************************************** +void MAX31856::spiDisable() +{ + ncs=1; //Set CS high to stop transmission (restarts conversion) + return; +} + + +//****************************************************************************** +bool MAX31856::registerReadWriteByte(uint8_t read_address, uint8_t write_address, int clear_bits, uint8_t val) +{ + uint8_t buf_read[2]; + + //Read the current contents of a register + spiEnable(); + for(int i=0; i<2; i++) { + buf_read[i]=spi.write(read_address); + } + spiDisable(); + + //Modify contents pulled from the register + buf_read[1]&=clear_bits; //Clear the contents of bits of parameter you are trying to clear for later or equal operation + buf_read[1]|=val; //Bitwise OR the input parameter with cleaned buf_read[1] to create new byte + val=buf_read[1]; + + //Write the updated byte to the register + spiEnable(); + buf_read[0]=spi.write(write_address); + buf_read[1]=spi.write(val); + spiDisable(); + return 1; +} + + +//****************************************************************************** +bool MAX31856::registerWriteByte(uint8_t write_address, uint8_t val) +{ + //Write the updated byte to the register + spiEnable(); + spi.write(write_address); + spi.write(val); + spiDisable(); + return true; +} + +//****************************************************************************** +uint8_t MAX31856::registerReadByte(uint8_t read_address) +{ + uint8_t buf_read, buf_write=read_address; + spiEnable(); + buf_read=spi.write(buf_write); + buf_read=spi.write(buf_write); + spiDisable(); + return buf_read; +} + +//****************************************************************************** +void MAX31856::calculateDelayTime() { + uint32_t temp_int; + + if (conversion_mode==0 || thermocouple_conversion_count==0) { + if (filter_mode==0) //60Hz + temp_int=82+(samples-1)*33.33f; + else //50Hz + temp_int=98+(samples-1)*40.00f; + } + else { + if (filter_mode==0) //60Hz + temp_int=82+(samples-1)*16.67f; + else //50Hz + temp_int=98+(samples-1)*20.00f; + } + + if (cold_junction_enabled==0) //cold junction is disabled enabling 25 millisecond faster conversion times + temp_int=temp_int-25; + conversion_time=1000*temp_int; //set private member conversion time to calculated minimum wait time in microseconds + return; +} + +//***************************************************************************** +MAX31856::~MAX31856(void) +{ + //empty block +} +