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Created April 8, 2023 22:07
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Arduino sketch to receive bytes from Serial Port 1 and print them in hex to the Serial Monitor
This simple sketch receives bytes on the hardware serial port
and echos it to the Arduino Serial Monitor (over USB)
The bytes are printed out as a hexadecimal string
This sketch requires an Arduino that has a separate
serial port for the USB port - such as the Arduino Leonardo
Serial: Serial Monitor (USB)
Serial1: Hardward serial (Pins 0 and 1) connected
The enablePin is used to configure a RS-485 transceiver into receive mode.
Author: Nicholas Humfrey
int enablePin = 2;
uint8_t buffer[256];
void setup()
// Configure Serial1 (hardware serial port)
pinMode(enablePin, OUTPUT);
digitalWrite(enablePin, LOW);
// Configure USB Serial
while (!Serial);
Serial.println("RS-485 Echo Sketch Started");
void loop()
int available = Serial1.available();
if (available > 0)
Serial.print(available, DEC);
Serial.println(" bytes available");
int read = Serial1.readBytes(buffer, sizeof(buffer));
Serial.print(read, DEC);
Serial.println(" bytes read");
for(int i=0; i<read; i++) {
int n = buffer[i];
Serial.print(n < 16 ? "0" : "");
Serial.print(n, HEX);
Serial.print(" ");
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