Definition of my_board.json for Atmega32U4 custom board

I retried to enter the code on my board withour pressing the reset button again, and now this error message appears:

Do I need to press the reset button? While pressing the reset button, this message appears:

I’m out of my depth here, you may have better chances at the general Arduino forum or AVRdude discussion in regards to what protocol / flags you need for flashing: avrdudes/avrdude · Discussions · GitHub

Ok, thank you nevertheless.

But do I have to press the reset button or not?

I received good help here regarding the flashing of the firmware:

Now I would like to send some data from the custom board to a terminal prgram via the serial interface. Unfortunately, I can’t select a serial port that belongs to my board in Docklight, for example. Do I have to install any drivers? Or have I possibly installed the wrong one?
Thanks in advance!

Well what’s the sketch you’re uploading to the board? Does it have Serial.begin(); in it?

It’s this:

void setup() {
// put your setup code here, to run once:

String inString = “”;

while(Serial.available() > 0)
char inChar =;
inString += inChar;
if(inString != “”)
Serial.println("Input string: ");

Do I need a USB terminal programme, instead of a virtual com-port terminal programm, to communicate between my custom board and the PC?

Before doing any of the more complicated USB / TFT stuff, have you verified that you can blink a simple LED?

change LED_BUILTIN to whatever, pin mapping is per here.

If that’s not working, something is totally not right. You might be running into a situation where the sketch is being uploaded to the wrong address with regards to your chip’s currently set fuses / no Arduino bootloader situation, thus resulting in nothing being run actually.