First step : check that the raspberry pi provide serial outputs as expected :
To activate this in hardware config activate " WRITEUSERDEVICE " .
Nothing more is needed for this first step.
By default Raspberry serial0 is selected, this is connected to GPIO 14 (TX ) and GPIO 15 (RX )
And default baudrate is 115200 Baud.
You should check that the data is available on the TX pin ( GPIO 14 ) with an oscilloscop or just a led.
Note refer to this to double check that you are using the correct raspberry pi GPIO :
You can also use simple this arduino sketch:
// Connect RX arduino pin digital 0 to Raspberry Pi Tx Pi Gpio 14 // Connect Arduino GND and Raspberry Pi GND // Either connect Arduino 5V to Raspberry pi 5V or connect Arduino USB on your computeur. // If some data is received, the led will be on and text will be display on Serial monitor if arduino is connected with USB // If no data the led will stay off. #define LED 13 void setup() { // put your setup code here, to run once: Serial.begin(115200); pinMode(LED, OUTPUT); } void loop() { // put your main code here, to run repeatedly: if (Serial.available()) { // Data received digitalWrite(LED, HIGH); int incomingByte = Serial.read(); Serial.print("I received: "); // Display received data Serial.println(incomingByte, DEC); } else { digitalWrite(LED, LOW); } }