/*  p2_3b.c: Toggling LEDs using special function registers by their names defined in the TivaWare header file */

#include <stdint.h>
#include "C:\ti\TivaWare_C_Series-1.1\inc\tm4c123gh6pm.h"

void delayMs(int n);

int main(void)
{
    /* enable clock to GPIOF at clock gating control register */
    SYSCTL_RCGCGPIO_R |= SYSCTL_RCGCGPIO_R5;
    /* enable the GPIO pins for the LED (PF3, 2 1) as output */
    GPIO_PORTF_DIR_R = 0x0E;
    /* enable the GPIO pins for digital function */
    GPIO_PORTF_DEN_R = 0x0E;

    while(1)
    {
        GPIO_PORTF_DATA_R = 0x0E;   /* turn on all LEDs */
        delayMs(500);

        GPIO_PORTF_DATA_R = 0;      /* turn off all LEDs */
        delayMs(500); 
    }
}

/* 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. */ 
    NVIC_CPAC_R |= 0x00F00000;
}