9XR(AT128) bricked, HVPP unbriked and then briked again.

[jhsa]

I tend to agree with you on getting another chip.
Your resistance readings seem normal.
Can you do something else please?
Measure the voltage on pins 11, 12, and 13, while the radio is ON of course buttons pressed, and not pressed.
Be careful not to short anything you shouldn't

João

[danielvc]

I tend to agree with you on getting another chip.
Your resistance readings seem normal.
Can you do something else please?
Measure the voltage on pins 11, 12, and 13, while the radio is ON of course buttons pressed, and not pressed.
Be careful not to short anything you shouldn't

João

Of course...
here it is:

strange voltage on the same pins Mike said.

[MikeB]

You could try adding a 10K pullup resistor to the signals and see if it gets the radio working. You should be able to wire these to the switches rather than the processor pins.

Mike

[jhsa]

Reading the table you posted above we can see that the pins 11, 12 and 13 are sinking the voltage to ground. So it means they are damaged. Probably when doing the HV programming or by some ESD..

Perhaps adding a 10K resistor as Mike suggested could make them work but I gotta say, I have seen this problem in the past and don't remember seeing this work. Maybe I am wrong, and I hope I am wrong, but I think that the only solution here is another chip. Go for an m2561 instead of the m128. It also doubles the RAM..

Just my 2 cents

João

[bob195558]

Some info here about upgrading to the 2561 chip, if needed here: (viewtopic.php?f=95&t=3819&start=120#p74105).

[danielvc]

You could try adding a 10K pullup resistor to the signals and see if it gets the radio working. You should be able to wire these to the switches rather than the processor pins.

Mike

I just bought a new chip.
In a few days it should arrive.

I decided to test Mike's idea out of curiosity.

it pass the first screen, but I think the chip still has other problems ...

[MikeB]

That shows the MENU button is being detected as still pressed (pin 11 is still low). The EXIT button is not pressed.
You could measure the voltage on pin 11 with the pullup in place.

Mike

[danielvc]

That shows the MENU button is being detected as still pressed (pin 11 is still low). The EXIT button is not pressed.
You could measure the voltage on pin 11 with the pullup in place.

Mike

2 volts when MENU button not pressed.
0.3 volts when MENU button pressed.

[MikeB]

So the 10K isn't pulling the MENU signal up enough! That does suggest damage to the CPU.
You could try a lower value resistor (4K7?) and see if the MENU signal get high enough to appear OFF (high).

Mike

[danielvc]

So the 10K isn't pulling the MENU signal up enough! That does suggest damage to the CPU.
You could try a lower value resistor (4K7?) and see if the MENU signal get high enough to appear OFF (high).

Mike

I added one more 10k resistor in parallel with what I had already put. Resulting in a 5k resistor.

As soon as I turned on the radio, I was able to get past the splash screen.

I tested the switchs / trims / sticks and they were all working properly.

but the MENU button was weird ... looking like it was pressed randomly.

I turned it off and turned the radio on again, then it froze again on the screen "LOADING MODEL01"

Looks like I unbrick the microcontroller, but I damaged some pins. In particular the pin 11.

Replacing the microcontroller should solve the problem.

[jhsa]

I think so, I wouldn't trust that chip anymore..

João

[danielvc]

I think so, I wouldn't trust that chip anymore..

João

I agree...

At least I've learned a lot in the last few weeks.

[jhsa]

Haven't we all??
For example, I think it was the first time I have seen damaged processor pins (with buttons) start working with external pullup resistors. I think this fix was attempted in the past, but it never worked. I might be wrong though, but I just don't remember

João

[danielvc]

just for the record ... I just changed the chip. the radio has returned to normal operation.


Many thanks Mike and Joao for the help.

[jhsa]

Nice to read this. Well done.. Did you use the m2561?

João

Sent from my BLN-L21 using Tapatalk

[danielvc]

Nice to read this. Well done.. Did you use the m2561?

João

Sent from my BLN-L21 using Tapatalk

I bought the Atmega128. I do not have many models. And the time for delivery was much longer.

Daniel

[jhsa]

It is not the number of models as the eeprom size is the same as the m128. It is the RAM size that is the double. This allow the radio to perform faster and allows for more features. The m2561 also has one more usable pin that could be used for an extra switch for example

João

[danielvc]

I did not know this... maybe an upgrade in the future...

[bob195558]

Some more info about Upgrading to the ATMEGA2561-16AU Chip, if needed:
(viewtopic.php?f=95&t=3819&start=120#p74105).