I am trying to connect my Pi 4 running Rasbian 2020 to an Arduino, after making all the connections I try to communicate with the Arduino by using Minicom. However, Minicom doe not respond to anything I am typing nor any of the commands such as ctrl + a.

I am running Minicom with the following command: minicom -b 9600 -o -D /dev/ttyAMA0

This is the code I have running on the Arduino:

byte number = 0;

void setup(){

void loop(){
if (Serial.available()) {
number = Serial.read();
Serial.print("character recieved: ");
Serial.println(number, DEC);
  • Have you uploaded some Serial code into your Arduino and set the bit rate ? /dev/ttyAMA0 exists on your RPI ? -o is really necessary ?
    – Ephemeral
    Mar 8, 2022 at 23:36
  • Yh, I do. I just put that up. Also, yes the baud rates match. Mar 8, 2022 at 23:40
  • From this example, your condition if (Serial.available()) {} must be if (Serial.available() > 0){} , I check if it is important
    – Ephemeral
    Mar 8, 2022 at 23:47
  • available -> Returns :The number of bytes available to read., For Arduino Mega the example code is the same as you.
    – Ephemeral
    Mar 8, 2022 at 23:49
  • Try to add int bytesSent = Serial.write("hello"); in your loop before if (Serial.available()) {} to see if you see anything in minicom ?
    – Ephemeral
    Mar 9, 2022 at 0:00

1 Answer 1


/dev/ttyAMA0 is connected to Bluetooth so this won't work.

See How do I make serial work on the Raspberry Pi3 or later

It IS POSSIBLE to disable Bluetooth but this is unnecessary to use serial. In the unlikely event you really need a fully featured UART the Pi4 has another 4.

There is no such thing as "Rasbian 2020"

  • Why do you think it is unnecessary to use Serial? and What do you mean by fully-featured UART? Mar 9, 2022 at 18:24
  • @BeulahAkindele "Why do you think it is unnecessary to use Serial" is said no such thing - re read the Answer.
    – Milliways
    Mar 9, 2022 at 23:03
  • @BeulahAkindele "What do you mean by fully-featured UART" the linked Answer explains the difference between mini UART & fully-featured UART.
    – Milliways
    Mar 9, 2022 at 23:04

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