Hi there
My ATMEGA48 resets itself unintentionally all 0.1 to 4 seconds at random
and after a while stops working at all.
The software is not expect to be the reason. I reduced it to minimum and
the same problem still occurs.
The supply voltage is 3.3V and batterypowered with a 10uF capacitor in
parallel.
I have connected a 10k pullup to Vcc and a 100nF capacitor to GND on the
reset pin. There is nothing else connected to the reset line. Just the
pullup resistor, the capacitor and a 6 pin connecter for the MKII
programmer.
If I measure the voltage on the reset pin with a oscilloscope there is a
voltage level of something as low as 0.8V to 1.3V without any worse
noise or spikes as long as it is not working properly. The uC does not
start because it's reset at the same moment again.
As soon as I connect the reset pin with a copperwire hard to vcc the
ATMEGA still almost resets and the LEDs start to flicker a bit.
So it seems to me that the reset pin draws a lot of current. (Measured
up to 20mA!)
The first time a day I connect the system to the battery it works fine
for some minutes but then it's getting worse every time i connect it to
the battery again.
Have you ever heard of such a behaviour? I would be very pleased if you
could give me a hint.
I've tried to solve this strange problem for about two weeks but
regardless of all my efforts it's still not working.