#include "nrf_gpio.h"
#include "nrf_delay.h"

// LED definitions
#define LED_PIN      7
#define LED_BIT      (1 << LED_PIN)

int main(void) {
  nrf_gpio_cfg_output(LED_PIN);
  while (1) {
    nrf_delay_ms(500);
    NRF_GPIO->OUT ^= LED_BIT;
  }
}