/* p10_1: Relay control
 *
 * This program turns the relay connected to PA10 on and off every second.
 *
 * Tested with Atmel Studio 7 v7.0.1006 and Keil MDK-ARM v5.21a.
 */

#include "samd21.h"

void delayMs(int n);

int main(void) {
    REG_PORT_DIRSET0 = 0x00000400;      /* make PA10 output */

    while(1) {
        REG_PORT_OUTSET0 = 0x00000400;  /* turn on PA10 */
        delayMs(1000);
        REG_PORT_OUTCLR0 = 0x00000400;  /* turn off PA10 */
        delayMs(1000);
    }
}

/* millisecond delay based on 1 MHz system clock */
void delayMs(int n) {
    int i;
    for (; n > 0; n--)
        for (i = 0; i < 199; i++)
            __asm("nop");
}