uart.cpp

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#include <wiringSerial.h>
#include <wiringPi.h>

#include <iostream>

using namespace std;

const char TURN_ON[]  = "Turn Led On";
const char TURN_OFF[] = "Turn Led Off";

int main(int argc, char const *argv[])
{
    int fd = serialOpen("/dev/ttyS0", 9600);

    if (fd == -1 || wiringPiSetup() == -1) {
        printf("UART PAS OK\n");
        exit(EXIT_FAILURE);
    }

    serialPrintf(fd, TURN_ON);
    delay(1000);
    int response;

    while (true) {
        if (serialDataAvail(fd)) {
            response = serialGetchar(fd);
            break;
        }
    }
    
    cout << response << endl;
    printf("%c\n", response);
    serialPrintf(fd, TURN_OFF);

    delay(200);    

    while (true) {
        if (serialDataAvail(fd) > 0) {
            cout << serialDataAvail(fd) << endl;
            for (int i = 0; i < serialDataAvail(fd); i++)
            {
                response = serialGetchar(fd);
            }
            break;
        }
    }

    cout << response << endl;

    serialClose(fd);
    
    return 0;
}