File content as of revision 10:4b907f32b4d4:

#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;
        }
    }
    checkFaultsThermocoupleThresholds();  //print any faults to the terminal
    
    thermocouple_conversion_count++; //iterate the conversion count to speed up time in between future converions in always on mode
}


//*****************************************************************************
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);
        LOG("Register containing\t\tsetOneShotMode\t\twas programmed with the parameter\t\tCR0_1_SHOT_MODE_NO_CONVERSIONS\r\n");
    }
    else if (val==CR0_1_SHOT_MODE_ONE_CONVERSION) { 
        return_val=registerReadWriteByte(ADDRESS_CR0_READ, ADDRESS_CR0_WRITE, CR0_CLEAR_BITS_6, val);
        LOG("Register containing\t\tsetOneShotMode\t\twas programmed with the parameter\t\tCR0_1_SHOT_MODE_NO_CONVERSIONS\r\n");
    }
    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, uint8_t 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 true;
}


//******************************************************************************
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
}