void setup() { // put your setup code here, to run once: afio_cfg_debug_ports(AFIO_DEBUG_SW_ONLY); Serial2.begin(9600); Serial.begin(); pinMode(PB5,OUTPUT); pinMode(PA15,OUTPUT); delay(100); // to be the device reciever, the digitals need to be set to low digitalWrite(PB5,LOW); digitalWrite(PA15,LOW); } void loop() { // put your main code here, to run repeatedly: int i; if (Serial2.available() > 0 ) { i = Serial2.read(); Serial.println(i); } }