Programing the USB controller on ARDUINO UNO

Development Tools IDE 1.x
1

Hi:
Recently I had problems with one of two ARDUINO UNO's
I changed the microcontroller from boards and they seem to be working as moving controller
from what I think is good board took the blink program with it into what I call bad board.
Good board will take new sketches and work everything fine.

I posted other message few days back , but got no help. From then I learned that the Arduino UNO
has a small controller You can program to do some tasks, in this case it should be programmed to work
as a USB controller (at least that is what I understood).

I unloaded FLIP and tried to load some drivers into the controller chip, but as PC will not even see, I
can not advance at all.

(Previous to this, I did the steps to move the bootloader into the "bad" board using "good" board as ISP programmer
and I got the succesfull transfer message, but when i tried to use the "bad" board, it will not be seen by PC).

Could someone reccomend a direction to continue trying to get this board working?
TKS

2

It sounds like the 8u2/16u2 chip that performs USB to serial conversion is not working on the bad board.

If the bad board is not even showing up in Device Manager, that is a good indication that chip is damaged or the firmware has been corrupted.

Here are the steps to try and use FLIP to reprogram the 8u2/16u2:

3

thanks for suggestion, but when I run flip, I can not open de USB serial port

This happens

  1. I plug the arduino

  2. I open FLIP

  3. I select ATMEGA 8U2

  4. I load the ARDUINO USB SERIAL UNO.HEX

  5. I check the file in buffer edit option

  6. I try to do communication USB option

  7. I select open usb

  8. small window that says COULD NOT OPEN USB DEVICE

  9. can not choose the program target device option