/* p7_2.c: Convert on-chip temperature */

/* This program converts the on-chip temperature sensor output using sample sequencer 3 and timer trigger at 1 Hz. */


#include "TM4C123GH6PM.h"

int main(void)
{
    volatile int temperature;

    /* enable clocks */
    SYSCTL->RCGCADC |= 1;       /* enable clock to ADC0 */
    SYSCTL->RCGCWTIMER |= 1;    /* enable clock to WTimer Block 0 */
   
    /* initialize ADC0 */
    ADC0->ACTSS &= ~8;          /* disable SS3 during configuration */
    ADC0->EMUX &= ~0xF000;       
    ADC0->EMUX |= 0x5000;       /* timer trigger conversion seq 0 */
    ADC0->SSMUX3 = 0;           /* get input from channel 0 */
    ADC0->SSCTL3 |= 0x0E;       /* take chip temperature, set flag at 1st sample */
    ADC0->ACTSS |= 8;           /* enable ADC0 sequencer 3 */
    
    /* initialize wtimer 0 to trigger ADC at 1 sample/sec */
    WTIMER0->CTL = 0;            /* disable WTimer before initialization */
    WTIMER0->CFG = 0x04;         /* 32-bit option */
    WTIMER0->TAMR = 0x02;        /* periodic mode and down-counter */
    WTIMER0->TAILR = 16000000;   /* WTimer A interval load value reg (1 s) */
    WTIMER0->CTL |= 0x20;        /* timer triggers ADC */
    WTIMER0->CTL |= 0x01;        /* enable WTimer A after initialization */

    while(1)
    {
        while((ADC0->RIS & 8) == 0) ;   /* wait for conversion complete */
        temperature = 147 - (247 * ADC0->SSFIFO3) / 4096;
        ADC0->ISC = 8;          /* clear completion flag */
    }
}

void SystemInit(void)
{
    /* Grant coprocessor access */
    /* This is required since TM4C123G has a floating point coprocessor */
    SCB->CPACR |= 0x00f00000;
}