/* p7_5.c: DAC programming to generate sine wave */
#include "TM4C123GH6PM.h"

void delayMs(int n);

uint8_t sineWaveLookup[]={128,192,238,255,238,192,128,64,17,0,17,64};
int main(void)
{
    uint8_t i = 0;
    SYSCTL->RCGCGPIO |= 0x02;   /* enable clock to GPIOB  */
    
    /* PORTB for DAC */
    GPIOB->DIR = 0xFF;         /* PORTB as output */
    GPIOB->DEN = 0xFF;         /* PORTB as digital pins */
    
    for (;;)
    {
        for (i = 0; i < 12; i++)
        {
            GPIOB->DATA = sineWaveLookup[i]; 
            i++;
            delayMs(5);
        }
    }
}

/* delay n milliseconds (16 MHz CPU clock) */
void delayMs(int n)
{
    int i, j;
    for(i = 0 ; i < n; i++)
        for(j = 0; j < 3180; j++)
            {} /* do nothing for 1 ms */
}

/* This function is called by the startup assembly code to perform system specific initialization tasks. */
void SystemInit(void)
{
    /* Grant coprocessor access
    /* This is required since TM4C123G has a floating point coprocessor */
    SCB->CPACR |= 0x00f00000;
}