Re: [avr-chat] proper voodoo caps for ATmega168 (28-pin DIP)

[Terry Karlson]

Joe Strout wrote:
...
> What are the recommended noise suppression capacitors for this chip?  Of 
> course I want one between VCC and ground (pins 7 and 8), but on the 
> other side, we have GND, AREF, and AVCC (pins 22 through 20).  I know 
> that AVCC should be connected to VCC "through a low-pass filter" (means 
> capacitor, nes pas?).  And my intuition is to put a cap between AVCC and 
> GND, but what about AREF?  Should we add one there too?

The section on the ADC in the datasheet has good explanations of how to 
connect these pins.

Also, for power supply decoupling and other general things see Atmel's 
application notes:

AVR042: AVR Hardware Design Considerations
AVR040: EMC Design Considerations

-Terry Karlson