5、继电器+LED（简单的io口）

#include <stdbool.h>
#include <stdint.h>
#include "nrf_delay.h"
#include "nrf_gpio.h"
#include "boards.h"

/**
* main() function
* @return 0. int return type required by ANSI/ISO standard.
*/
int main(void)
{
uint8_t output_state = 0;
uint8_t i;

// Configure LED-pins as outputs
nrf_gpio_range_cfg_output(LED_START, LED_STOP);
nrf_gpio_cfg_output(LED_GREEN);
nrf_gpio_cfg_output(LED_BLUE);
nrf_gpio_cfg_output(LED_RED);
nrf_gpio_cfg_output(RELAY);
nrf_gpio_pin_set(LED_GREEN);
nrf_gpio_pin_set(LED_BLUE);
nrf_gpio_pin_set(RELAY);

while(true)
{
for(i = 0; i < 7; i++)
{
nrf_gpio_pin_set(LED_RED);
nrf_gpio_pin_set(LED_BLUE);
nrf_gpio_pin_toggle(LED_GREEN);
nrf_gpio_pin_toggle(RELAY);
nrf_delay_ms(100);
nrf_delay_ms(100);
nrf_delay_ms(100);
}
for(i = 0; i < 7; i++)
{
nrf_gpio_pin_set(LED_RED);
nrf_gpio_pin_set(LED_GREEN);
nrf_gpio_pin_toggle(LED_BLUE);
nrf_gpio_pin_toggle(RELAY);
nrf_delay_ms(100);
nrf_delay_ms(100);
nrf_delay_ms(100);
}

for(i = 0; i < 7; i++)
{
nrf_gpio_pin_set(LED_GREEN);
nrf_gpio_pin_set(LED_BLUE);
nrf_gpio_pin_toggle(LED_RED);
nrf_gpio_pin_toggle(RELAY);
nrf_delay_ms(100);
nrf_delay_ms(100);
nrf_delay_ms(100);
}

}
}