#include "nrf52840.h"
#include "nrf52840_bitfields.h"


void init_gpio_p0_output(uint32_t pin_num)
{
  NRF_GPIO_Type * reg = ((NRF_GPIO_Type*)NRF_P0_BASE);
  reg->PIN_CNF[pin_num] = ((uint32_t)GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos)
                            |((uint32_t)GPIO_PIN_CNF_INPUT_Disconnect << GPIO_PIN_CNF_INPUT_Pos)
                            |((uint32_t)GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
                            |((uint32_t)GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
                            |((uint32_t)GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos);

}

void toggle_gpio_p0(uint32_t pin_num)
{
	NRF_GPIO_Type * reg = ((NRF_GPIO_Type*)NRF_P0_BASE);
	uint32_t        pins_state = reg->OUT;
	reg->OUTSET = (~pins_state & (1UL << pin_num));
	reg->OUTCLR = (pins_state & (1UL << pin_num));


}


int main()
{
  // gpio config for board PCA10056 LED1,2,3,4 = P0.13, P0.14, P0.15, P0.16.
  init_gpio_p0_output(13);  // LED1 on PCA10056
  init_gpio_p0_output(14);  // LED2 on PCA10056
  init_gpio_p0_output(15);  // LED3 on PCA10056
  init_gpio_p0_output(16);  // LED4 on PCA10056

  while(1)
  {
      // toggling the pin
		toggle_gpio_p0(13);
		toggle_gpio_p0(14);
		toggle_gpio_p0(15);
		toggle_gpio_p0(16);
  }

}