[avr-chat] AVR Chip running too hot

[Peter Harrison]

I too have a hot chip.

It is an ATMega128 on an Olimex carrier board.  For some time, the 
programmer (Atmel AVRISP, serial) would say it cannot enter programming 
mode. After a bit of fiddling, it would give in and program the chip. I 
assumed a dry joint somewhere as my fiddling seemed to make it work. In 
retrospect, it was like rolling a dice. Every now and then you would get 
a six but the result was actually random.

Finally, it would not program it any more. The programmer will program 
other targets so I took the carrier out of the project and tried it on 
the bench with a separate power supply. No joy. Noticed now that the 
processor was hot to the touch and was drawing 125mA !

So, is it cooked for ever? Can the IO go into some partially programmed 
latch-up state that I might fix if I can only get it programmed?

Just how dangerous is it to connect and disconnect the programmer with 
the target powered up. I know I shouldn't but...

Pete Harrison