UART communication between RP2040 and Uno

[tecrazy]

I am trying to communicate between RP2040 and Uno but I am unable to get the Serial connection. I have connected the TX of Nano to RX of Uno and vice versa also connected the GND of both.

Here's my code for Uno:

void setup() {
  Serial.begin(9600); // set up serial communication at 9600 baud
  Serial.setTimeout(50);
  delay(100);
}

void loop() {
  String message = " ";
  if (Serial.available()){
    message = Serial.readString();
    Serial.println(message);
    delay(100);
  }
}

Here's my code for Nano:

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  delay(100);

}

void loop() {
  // put your main code here, to run repeatedly:
  Serial.print("ON");
  delay(2000);

}

[gilshultz]

What about the terminal, it is also connected to that port?

[tecrazy]

I think I know what the problem is. The operating voltage is different on both devices. Might need to use a level shifter

[westfw]

@tecrazy

Here's my code for Nano:

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);

"Serial" on the rp2040 Nano is going to be the USBSerial port. try Serial1.