I made an Arduino on a prototyping board. I connected a led and resistor to output 13.
The problem is as follows:
the prototype works great with an atmega8 (the led blinks every second) but once I use an atmega168 nothing works anymore: sometimes the led blinks too quickly and erraticly, sometimes it just never turns on.
What can the problem be? Why could it work with an atmega8 and not an atmega168?
I am using the following clock source: