Hello Fellow Freaks,
I've just assembled a very small board to be used as as generic controller "core" based on an AT90S2313. The circuit is very very simple as you can see in the picture below.
However, I have this strange behaviour: after I power it up, the AVR will only run for a few seconds and then stop. After the first run, I need to let it turned off for some time to be able to power it again and it will run for a few seconds only, again.
Doing some measurement I found that the reset line is having a "capacitive" behaviour. After I power it up, it will start with a few volts and then it will start to fall until it reaches a few tenths of millivolts. So the AVR enters reset and the program stops. It looks like there's a capacitor somewhere that charges slowly (the few seconds) and controls the RESET line. Odd, hun? In a first fixing attempt I removed the cap on the RESET line, but it obviously (now thinking) did no change.
Now, I would say that the chip probably got ruined during soldering, but I would like to know if someone else has any other theory...