#include <wiringPi.h>
#include <stdio.h>

#define LED_PIN  26
#define DELY_MS  1000

int main(void)
{
    wiringPiSetup();
    pinMode(LED_PIN, OUTPUT);

    while(1)
    {
        //led GPIO引脚置高电平,灯灭
        digitalWrite(LED_PIN, HIGH);
        printf("X\n");
        delay(DELY_MS);

        //led GPIO引脚置低电平,灯亮
        digitalWrite(LED_PIN, LOW);
        printf("O\n");
        delay(DELY_MS);
    }

    return 0;
}