Get the number of bytes (characters) available for reading from the serial port. This is data that's already arrived and stored in the serial receive buffer (which holds 128 bytes).
Serial.available()
Arduino Mega only:
Serial1.available()
Serial2.available()
Serial3.available()
none
the number of bytes available to read
int incomingByte = 0; // for incoming serial data
void setup() {
Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
}
void loop() {
// send data only when you receive data:
if (Serial.available() > 0) {
// read the incoming byte:
incomingByte = Serial.read();
// say what you got:
Serial.print("I received: ");
Serial.println(incomingByte, DEC);
}
}
Arduino Mega example:
void setup() {
Serial.begin(9600);
Serial1.begin(9600);
}
void loop() {
// read from port 0, send to port 1:
if (Serial.available()) {
int inByte = Serial.read();
Serial1.print(inByte, BYTE);
}
// read from port 1, send to port 0:
if (Serial1.available()) {
int inByte = Serial1.read();
Serial.print(inByte, BYTE);
}
}