How to restore "COM" capabilities on Arduino Leonardo


I'm working on an Leonardo board. I have a Atmel JTag ICE, working with Atmel Studio. So I managed to burn my own programm succesfully.

The problem is that now, when running, the Leonardo do not "show" a "COM" port on my PC. I would like to reload a Sketch from Arduino IDE, but without COM port, AVRdude is not working!

Is there a way to either:

  • Force the Leonardo to mount a COM port?
  • Reload with Atmel Studio and JTag a firmware that will bring up the "COM" port?

The aim of that is to allow someone without JTag to reload new version of the firmware.

Also, when building application with Atmel Studio, what should be "included" in the project to bring up the COM port to allow the use of AVRdude.

Thank you

I have load a firmware (with AS and JTag) that just do the following:



So now I have a COM on the PC. However loading Sketch with Arduino IDE still do not work!

You probably could have fixed it by just double-tapping the reset button - usually what happens is that the sketch hoses the USB functionality, so you can't upload to it except during a couple of seconds after a hardware reset. But doubletapping reset will make it wait in bootloader for a new sketch.

But now, since you've uploaded code via atmel studio, you've erased the bootloader. You must now reload the bootloader on the chip.

Why can't you use an ISP programmer and the Arduino IDE?

The Arduino Leonardo bootloader is here:

If you want to use the Arduino IDE to flash that bootloader to your Leonardo, I know they have added support for the Atmel JTAGICE3 but it's not clear whether you own version 3 of that device or one of the earlier JTAGICE models, which are not supported by the Arduino IDE. If you do have the JTAGICE3 you could try this in the Arduino IDE:

  • Tools > Board > Arduino Leonardo
  • Tools > Programmer > Atmel JTAGICE3 (I guess whether you should chose the "JTAG mode" or "ISP mode" option depends on how you have the programmer connected to your Leonardo)
  • Tools > Burn Bootloader