How to burn a bootloader "Leonardo" in Atmega32U4

Hello,
I am developping a special sheet using an Atmaga32U4, apart from the Arduino board.
And I would like to burn the booloader "Leonardo" in the Atmega32U4, in order to develop within the Arduino environment.
For that, I used the ICSP connections with an external "STK500 programmer" and applied two different methods ; but none of them work !!
I checked the hardware connections, the proper supply levels (5V) on my sheet ==> everything is ok.

  • 1st method : using Arduino IDE, selection of "Arduino Leonardo" board and "Atmel STK500" programmer ==> "Tools\Burn Bootloader" ==> I received an error message ==> trying to modify the "avrdude.conf" file ==> no more error, only warnings.
    ==> The bootloader has been achieved, but the usb communication with the PC does not work ; the µC µC looks like not alive.

  • 2nd method : using Atmel Visual Studio7, programming "Caterina-leonardo.hex", configuring the fuses : low 0x5E, high 0x99, ext 0xF3.
    ==> Same conclusion : The burning has been achieved, but the usb communication with the PC does not work ; the µC looks like not alive.

I really do not know what to to.
Can somebody help ?
I would be very gratefull, thanks in advance.

Brlefvre:
and “Atmel STK500” programmer

There is no Programmer menu selection of that name. Do you mean “Atmel STK500 development board”?

Brlefvre:
I received an error message

Don’t you think it would be helpful to tell us what the error message was?

Please do this:

  • File > Preferences > Show verbose output during: > compilation (uncheck) > upload (check) > OK
  • Tools > Burn Bootloader
  • After the process fails you’ll see a button on the right side of the orange bar “Copy error messages”. Click that button.
  • Paste the error messages in a reply here USING CODE TAGS (</> button on the toolbar).

Brlefvre:
trying to modify the “avrdude.conf” file

Don’t you think it would be helpful to tell us exactly what modifications you made?

Brlefvre:
the usb communication with the PC does not work ; the µC µC looks like not alive.

Please explain exactly what you mean by that.

Hello, and thanks for this first feedback,
Hereafter the replies to your questions,

1- “Atmel STK500 development board” : yes, it is, exactly (sorry for the wrong definition).

2- “What the error message was” : I will copy the message, if you think it is helpful (cannot do now, because, I have not the material available right now).
The message was related to “undefined bit lock that should be set to 1”

3- “What modifications I made on avrdude.conf” : many modifications arround the bit values of “memory locks”, changing “x” by “1” or changing “i” by “1”; finally, I replaced the entire file by another one downloaded from the web ; all those manipulations did not help.

3- “Please explain exactly what you mean by “the usb communication with the PC does’nt work””,
My final objective is to be able to domnload applications in Arduino environment, using the usb connection (virtual serial communication).
Once bootloaded, I suppose that the Atmega32U4 is able to communicate with a PC through the Rx/Tx serial protocol ==> when I plug an usb cable between my shield and the PC, a virtual serial port should be generated, and that never occurs : no reaction when I plug the usb cable.