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Topic: UNO stopped uploading (Read 1 time) previous topic - next topic

James C4S

my UNO stopped uploading after several week of use.

It is possible, but not likely, you have burned up one of the flash cells and the ATmega can longer be programmed.

it show that the previous application run and reset(restart) in an endless loop.

Press and hold the RESET button on the Arduino, while starting the complie/upload process on the PC.  When the "Sketch Size" message appears wait 1-2 seconds and release the RESET button.  Try that a couple of times.  You might also try holding down RESET before applying power to the Arduino.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com


I already tried all that several trial of pushing down th reset button during upload and during poweron . No way to overcome the problem.

I will try to upload trought an external programmer ( a second arduino uno with the avrisp application conneted to the ISP ).I hope this work ....I will let you know.


James C4S

If ISP does not work, then you have probably burned out one of the flash cells in the chip.  :-/
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com


Finaly after reburning of the bootloader,I solved my problem.
I can now upload, as usual, through the serial port.
Fotunately there has not been any damage to the board and processor.
It appear that the application I have loaded was looking the UNO:
I strongly suggest that it become possible without reburning everithing the remove a locking application. One suggestion anyhow could be to alwais start with delay(5000) as first statement in setup() function to avoid this append again.
Thank you for all yuor suggestions.



My Uno stopped uploading as well. I get a message like Paolo's:
avrdude: verification error, first mismatch at byte 0x0000
             0x0c != 0x00
avrdude: verification error; content mismatch

Everything was working very well till such time as I accidentally connected 9V to the 5V Uno output, although very briefly. Might I have damaged the two microcontrollers (ATMEGA8U2-MU and ATMEGA8) on my Uno board? According to their datasheets neither can tolerate > 6V on their supply pins.

I tried the reset-button trick that James suggested. I get the following message when I let go the reset button:
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51.

I wonder if I have irreversibly damaged my Uno. I could replace the ATMEGA8, the DIP chip, but I don't think I even want to try replacing the ATMEGA8U2-MU (TQFP32).

Any suggestions would be most welcome.

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