/*
 * Toggle the four LEDs on the Digilent Orbit BoosterPack.
 * The LEDs are connected to the MCU as:
 * LD1 PC6
 * LD2 PC7
 * LD3 PD6
 * LD4 PB5 
 * Default system clock 16 MHz is used.
 */

#include "TM4C123GH6PM.h"

void delayMs(int n);

int main(void) {
    volatile unsigned char readback;

    SYSCTL->RCGCGPIO |= 0x0E;       // enable clock to GPIOB, GPIOC, GPIOD
    readback = SYSCTL->RCGCGPIO;    // make sure the clock is enabled
    GPIOC->DIR |= 0xC0;             // set PORTC 7, 6 as output pins
    GPIOC->DEN |= 0xC0;             // set PORTC 7, 6 as digital pins
    GPIOD->DIR |= 0x40;             // set PORTD 6 as output pins
    GPIOD->DEN |= 0x40;             // set PORTD 6 as digital pins
    GPIOB->DIR |= 0x20;             // set PORTB 5 as output pins
    GPIOB->DEN |= 0x20;             // set PORTB 5 as digital pins

    for (;;) {  // infinite loop
        GPIOC->DATA &= ~0x40;       // turn off LD1
        GPIOB->DATA |= 0x20;        // turn on LD4
        delayMs(500);
        GPIOB->DATA &= ~0x20;       // turn off LD4
        GPIOD->DATA |= 0x40;        // turn on LD3
        delayMs(500);
        GPIOD->DATA &= ~0x40;       // turn off LD3
        GPIOC->DATA |= 0x80;        // turn on LD2
        delayMs(500);
        GPIOC->DATA &= ~0x80;       // turn off LD2
        GPIOC->DATA |= 0x40;        // turn on LD1
        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
    SCB->CPACR |= 0x00f00000;
}