File content as of revision 0:456e9e702d57:

#include <mbed.h>
#include "MAX31856.h"

#define LOG(args...)    printf(args)

MAX31856::MAX31856(SPI& _spi, PinName _ncs, uint8_t _type, uint8_t _fltr) : spi(_spi), ncs(_ncs)//, setThermocoupleType(_type), setEmiFilterFreq(_fltr)
{
    setThermocoupleType(_type);
    setEmiFilterFreq(_fltr);
}

float MAX31856::readTC()
{
    int32_t temp;
    uint8_t buf_read[4], buf_write=MAX31856_ADDRESS_LTCBH_READ;
    
    spiEnable();
    for(int i=0; i<4; i++)
    {
        buf_read[i]=spi.write(buf_write);
    }
    spiDisable();
    
    //Convert the registers contents into the correct value
    temp =((int32_t)(buf_read[1] << 16));       //Shift Byte 2 into place
    temp|=((int32_t)(buf_read[2] << 3));        //Shift Byte 1 into place
    temp|=((int32_t)(buf_read[3] >> 5));        //Shift Byte 0 into place
    float val=((float)(temp/128.0));            //Divide the binary string by 2 to the 7th power
    return val;
}

float MAX31856::readCJ()
{
    int32_t temp;
    uint8_t buf_read[3], buf_write=MAX31856_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
    
    return val;
}

bool MAX31856::setNumSamplesAvg(uint8_t val)
{   
    int return_val;
    //Check if the parameter passed in is valid
    if (val==MAX31856_CR1_AVG_TC_SAMPLES_1 || val==MAX31856_CR1_AVG_TC_SAMPLES_2 || val==MAX31856_CR1_AVG_TC_SAMPLES_4 || val==MAX31856_CR1_AVG_TC_SAMPLES_8 || val==MAX31856_CR1_AVG_TC_SAMPLES_16)
    {
        uint8_t buf_read[2], buf_write=MAX31856_ADDRESS_CR1_READ;
        //Read the current contents of CR1
        spiEnable();
        for(int i=0; i<2; i++)
        {
            buf_read[i]=spi.write(buf_write);
        }
        spiDisable();
        //Modify contents of CR1
        buf_read[1]&=MAX31856_CR1_CLEAR_PREV_VOLT_AVG_SAMPLES;  //Clear the contents of bits 6:4 of CR1 to 000 to set new parameter
        buf_read[1]|=val;                                       //Bitwise OR the input parameter with cleaned buf_read[1] to create new byte for CR1
        buf_write=buf_read[1];
        //Write the contents of CR1 with the updated bits 6:4 needed for setting number of samples to average
        spiEnable();
        for(int i=0; i<2; i++)
        {
            buf_read[i]=spi.write(buf_write);
        }
        spiDisable();
        return_val=1; //returns a 1 to flag that the parameter was programmed
    }
    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;
}

bool MAX31856::setThermocoupleType(uint8_t val)
{   
    int return_val;
    //Check if the parameter passed in is valid
    if (val==MAX31856_CR1_TC_TYPE_B || val==MAX31856_CR1_TC_TYPE_E || val==MAX31856_CR1_TC_TYPE_J || val==MAX31856_CR1_TC_TYPE_K || val==MAX31856_CR1_TC_TYPE_N || val==MAX31856_CR1_TC_TYPE_R || val==MAX31856_CR1_TC_TYPE_S || val==MAX31856_CR1_TC_TYPE_T || val==MAX31856_CR1_TC_TYPE_VOLT_MODE_GAIN_8 || val==MAX31856_CR1_TC_TYPE_VOLT_MODE_GAIN_32)
    {
        uint8_t buf_read[2], buf_write=MAX31856_ADDRESS_CR1_READ;
        //Read the current contents of CR1
        spiEnable();
        for(int i=0; i<2; i++)
        {
            buf_read[i]=spi.write(buf_write);
        }
        spiDisable();
        //Modify contents of CR1
        buf_read[1]&=MAX31856_CR1_CLEAR_PREV_TC_TYPE;  //Clear the contents of bits 3:0 of CR1 to 0000 to set new thermocouple type
        buf_read[1]|=val;                                       //Bitwise OR the input parameter with cleaned buf_read[1] to create new byte for CR1
        val=buf_read[1];
        //Write the contents of CR1 with the updated bits 6:4 needed for setting new thermocouple type
        spiEnable();
        for(int i=0; i<2; i++)
        {
            buf_read[i]=spi.write(buf_write);
        }
        spiDisable();
        return_val=1; //returns a 1 to flag that the parameter was programmed
    }
    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;
}


bool MAX31856::changeOneBit(uint8_t address, uint8_t val)
{   
    uint8_t inverse_val=~(val), buf_read[2], buf_write=address;
    //Read the current contents of a register
    spiEnable();
    for(int i=0; i<2; i++)
    {
        buf_read[i]=spi.write(buf_write);
    }
    spiDisable();
    //Modify contents of CR1
    buf_read[1]&=inverse_val;  //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(address);
    buf_read[1]=spi.write(val);
    spiDisable();
    return true;
}



void spiEnable()
{
    ncs=1; //Set CS high to start transmission (interrupts conversion)
    return;
}
void spiDisable()
{
    ncs=0; //Set CS low to stop transmission (restarts conversion)
    return;
}