RCC_ClocksTypeDef RCC_Clocks;

    // SysTick end of count event each 1ms

    RCC_GetClocksFreq(&RCC_Clocks);

    SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);

    GPIO_ResetBits(LED_STAT);

    Delay(100);

    GPIO_SetBits(LED_POWER);

    Delay(500);

    GPIO_ResetBits(LED_POWER);

    init_spi();

    ssd1306_Init();

    ssd1306_block_write();

    ssd1306_DrawString("therm 0.1", 0, 40);

    ssd1306_DrawString("Status: Idle", 2, 40);

  //  ssd1306_block_write();

    ssd1306_test();

    uint8_t toggle = 0;

    int16_t temp = -231;

    while(1)

    {

        //ssd1306_block_write();

        // Process sensor inputs [TODO: 5hz?]

        process();

        // Run state machine [TODO: 50hz?]

        machine(); 

        // probably just passed the actual port

        // TODO: Grab buttonpresses with interrupts

        uint8_t sw_btn = GPIO_ReadInputDataBit(SW_BTN);

        //uint8_t sw_up = GPIO_ReadInputDataBit(SW_UP);

        //uint8_t sw_down = GPIO_ReadInputDataBit(SW_DOWN);

        //uint8_t sw_left = GPIO_ReadInputDataBit(SW_LEFT);

        //uint8_t sw_right = GPIO_ReadInputDataBit(SW_RIGHT);

        if(!sw_btn) {

            GPIO_ToggleBits(LED_STAT);

            if(!toggle) {

                GPIO_SetBits(GPIOB, GPIO_Pin_13);

                toggle = ! toggle;

            }

            else  {

                GPIO_ResetBits(GPIOB, GPIO_Pin_13);

                toggle = ! toggle;

            }    

        }

        GPIO_SetBits(LED_POWER);

        Delay(50);

        GPIO_ResetBits(LED_POWER);

        Delay(50);

    }

}

int32_t temp = 0;

int32_t setpoint = 0;

int32_t p = 1;

int32_t i = 1;

int32_t d = 1;

// Process things

void process()

{

    // Assert CS

    GPIO_ResetBits(MAX_CS);

    Delay(1);

    // This may not clock at all... might need to send 16 bits first

    SPI_I2S_SendData(SPI2, 0xAAAA); // send dummy data

    //SPI_I2S_SendData(SPI2, 0xAA); // send dummy data

    uint16_t temp_pre = SPI_I2S_ReceiveData(SPI2);

    if(temp_pre & 0b0000000000000010) {

        ssd1306_DrawString("Fatal Error", 3, 35);

    }

    else if(temp_pre & 0b0000000000000001) {

        ssd1306_DrawString("TC Fault", 3, 35);

    }

    else {

        ssd1306_DrawString("TempSense OK", 3, 35);

    }

    uint8_t sign = temp >> 15;// top bit is sign

    temp_pre = temp_pre >> 2; // Drop 2 lowest bits

    int16_t temp = 0;

    if(sign) {

        temp = -temp_pre;

    }

    else {

        temp = temp_pre;

    }

    // Deassert CS

    Delay(1);

    GPIO_SetBits(MAX_CS);

    //////////////////////////

    // Calc internal temp   //

    //////////////////////////

/*    temp = temp >> 4; // Drop last 4 bits, no need for them

    float internal_temp = temp & 0x7FF // Lower 11bits are internal temp

    // Check internal temp sign

    if(temp & 0x800) {

        // Convert to negative value by extending sign and casting to signed type.

        int16_t tmp = 0xF800 | (temp & 0x7FF);

        internal_temp = tmp;

    }

    internal_temp *= 0.0625; // LSB = 0.0625 degrees

    // Now we have a good internal temp!

*/

    //////////////////////////

    // Calc external temp   //

    //////////////////////////

    if(temp > 0) {

        GPIO_SetBits(LED_STAT);

    }

    char tempstr[9];

    itoa(temp_pre, tempstr);

    ssd1306_DrawString("Temp: ", 1, 40);

    ssd1306_DrawString("    ", 1, 70);

    ssd1306_DrawString(tempstr, 1, 70);

/*

    if((!retval || (temp & 0x2) != 0))

    {

        ssd1306_DrawString("!TempCOMMS", 3, 35);

        //return; // Comms error - this is happening right now

    }

    else if((temp & 0x4)!= 0)

    {

        ssd1306_DrawString("!OpenThermocouple", 3, 40);

        //return; // Open thermocouple

    }

    temp = (temp & 0x7FF8) >> 5;

*/

    // TODO: Add calibration offset (linear)

    // Perform PID calculations

    // Write output to SSR

}

enum state {

    STATE_IDLE = 0,

    STATE_SETP,

    STATE_SETI,

    STATE_SETD,

    STATE_PREHEAT_BREW,

    STATE_MAINTAIN_BREW,

    STATE_PREHEAT_STEAM,

    STATE_MAINTAIN_STEAM,

};

uint8_t state = STATE_IDLE;

// State machine

void machine()

{

    switch(state)

    {

        // Idle state

        case STATE_IDLE:

        {

            // Write text to OLED

            // [ therm :: idle ]

            ssd1306_DrawString("therm :: idle ", 0, 40);

            // Button handler

            if(!GPIO_ReadInputDataBit(SW_BTN)) {

                state = STATE_SETP;

            }

            // Event Handler

            // N/A

        } break;

        case STATE_SETP:

        {

            // Write text to OLED

            // [ therm :: set p ]

            // [ p = 12         ]

            ssd1306_DrawString("therm :: set p", 0, 40);

            // Button handler

            if(!GPIO_ReadInputDataBit(SW_BTN)) {

                state = STATE_SETI;

            }

            // Event Handler

            // N/A

        } break;

        case STATE_SETI:

        {

            // Write text to OLED

            // [ therm :: set i ]

            // [ i = 12         ]

            ssd1306_DrawString("therm :: set i", 0, 40);

            // Button handler

            if(!GPIO_ReadInputDataBit(SW_BTN)) {

                state = STATE_SETD;

            }

            // Event Handler

            // N/A