#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>

// set correct serial path
#define SERIAL_PORT "/dev/ttyS2"

int main() {
    int serial_port;
    struct termios tty;
    
    // open
    serial_port = open(SERIAL_PORT, O_RDWR | O_NOCTTY);
    if (serial_port < 0) {
        perror("Error opening serial port");
        return 1;
    }
    
    // Configuration of serial
    memset(&tty, 0, sizeof(tty));
    if (tcgetattr(serial_port, &tty) != 0) {
        perror("Error getting serial port attributes");
        close(serial_port);
        return 1;
    }
    
    cfsetospeed(&tty, B921600); // set correct baud rate
    cfsetispeed(&tty, B921600);
    
    tty.c_cflag |= (CLOCAL | CREAD);
    tty.c_cflag &= ~PARENB;     
    tty.c_cflag &= ~CSTOPB;     
    tty.c_cflag &= ~CSIZE;
    tty.c_cflag |= CS8;         
    
    // write configration to serial
    if (tcsetattr(serial_port, TCSANOW, &tty) != 0) {
        perror("Error setting serial port attributes");
        close(serial_port);
        return 1;
    }
    
    // loop test
    while (1) {
        // receive data
        char received_data[64];
        if (read(serial_port, &received_data, sizeof(char)*64)) {
            // get data
            printf("Received: %s", received_data);
        }

        // Only send "Hello, UART!"
        char data_to_send[] = "Hello, UART!\n";
        write(serial_port, data_to_send, strlen(data_to_send));
        
        // sleep 100ms
        usleep(100000); 
    }
    
    // close
    close(serial_port);
    
    return 0;
}