/* Program 4-5: Serial1 loopback on Arduino Mega 
 * 
 * Connect a wire between pin PD2 (RxD1) and pin PD3 (TxD1) of
 * the Mega 
 */

void setup() { 
    Serial.begin(9600);     /* initialize serial and set the Baud rate to 9600 */
    Serial1.begin(115200);    /* initialize serial1 and set the Baud rate to 9600 */
} 

void loop() {
    char c;
    
    if(Serial.available()) {    /* if a char is available */
        c = Serial.read();      /* read it */
        Serial1.write(c);       /* and write it to Serial1 */
    }
    
    if(Serial1.available()) {   /* if a char is available */
        c = Serial1.read();     /* read it */
        Serial.write(c);        /* and write it to Serial */
    }    
}