#include "stm32f0xx_hal.h"

#include "config.h"
#include "stringhelpers.h"
#include "states.h"
#include "gpio.h"


// Registers
#define MAX31855_REG_CONFIG 0x00
#define MAX31855_REG_RTD_MSB 0x01
#define MAX31855_REG_RTD_LSB 0x02
#define MAX31855_REG_HFAULT_THRESH_MSB 0x03
#define MAX31855_REG_HFAULT_THRESH_LSB 0x04
#define MAX31855_REG_LFAULT_THRESH_MSB 0x05
#define MAX31855_REG_LFAULT_THRESH_LSB 0x06
#define MAX31855_REG_FAULTSTATUS 0x07

#define MAX31855_REGWRITEMODIFIER 0x80

// Fields 
#define MAX31865_CONF_VBIAS (1<<7)
#define MAX31865_CONF_CONVMODE (1<<6)
#define MAX31865_CONF_1SHOT (1<<5)
#define MAX31865_CONF_3WIRE (1<<4)

#define MAX31865_CONF_FAULT_NOACTION    0b0000
#define MAX31865_CONF_FAULT_AUTODELAY   0b0100
#define MAX31865_CONF_FAULT_MANUALELAY1 0b1000
#define MAX31865_CONF_FAULT_MANUALELAY2 0b1100

#define MAX31865_CONF_FAULT_CLEAR (1<<1)
#define MAX31865_CONF_50_60HZ_FILTER (1<<0)


// Grab temperature reading from MAX31865
void max31865_readtemp(SPI_HandleTypeDef* hspi1, therm_settings_t* set, therm_status_t* status)
{
    ///////////////////////////////////
    // This is duplicated from MAX31855, update for MAX31865 registers/etc
    /////////////////////////////////// 

    // TODO: Set configuration register based on params in config.h (2-wire, 4-wire, etc RTD). This is register 0x00.
        // 2-wire RTC or 2-wire (duh) NTC thermistor will be the only options
        // Need option for resistance of RTD
        // These options should be stored in the set structure and should be menu-selectable
    // TODO: Read RTD msbs (0x01)
    // TODO: Read RTD LSBs (0x02)

    // Assert CS
    HAL_GPIO_WritePin(MAX_CS, 0);

    uint8_t rxdatah[1] = {0x00};
    uint8_t rxdatal[1] = {0x00};

    HAL_SPI_Receive(hspi1, rxdatah, 1, 100);
    HAL_SPI_Receive(hspi1, rxdatal, 1, 100);

    // Release CS
    HAL_GPIO_WritePin(MAX_CS, 1);

    // Assemble data array into one var
    uint16_t temp_pre = rxdatal[0] | (rxdatah[0]<<8);
    if(temp_pre & 0b001 && !set->val.ignore_tc_error) {
        status->tc_errno = 1;
        HAL_Delay(400); // FIXME: remove?
        status->state_resume = status->state;
        status->state = STATE_TC_ERROR;
        status->temp = 0;
        status->temp_frac = 0;
    }
    else 
    {
        uint8_t sign = status->temp >> 15;// top bit is sign
        temp_pre = temp_pre >> 2; // Drop 2 lowest bits
        status->temp_frac = temp_pre & 0b11; // get fractional part
        status->temp_frac *= 25; // each bit is .25 a degree, up to fixed point
        temp_pre = temp_pre >> 2; // Drop 2 fractional bits 

        int8_t signint;

        if(sign) {
            signint = -1;
        }
        else {
            signint = 1;
        }

        // Convert to Fahrenheit
        if(set->val.temp_units == TEMP_UNITS_FAHRENHEIT)
        {
            status->temp = signint * ((temp_pre*100) + status->temp_frac);
            status->temp = status->temp * 1.8;
            status->temp += 3200;
            status->temp_frac = status->temp % 100;
            status->temp /= 100;
            status->temp += set->val.temp_offset;
        }

        // Use Celsius values
        else
        {
            status->temp = temp_pre * signint;
            status->temp += set->val.temp_offset;
        }
    }
}

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