AVR-Chat

--- In AVR-Chat@yahoogroups.com, David VanHorn <dvanhorn@c...> wrote:

> My #1 rule for EMI:
> #2 rule:  etc.

David clearly understands EMI and I hope he's not offended by the 
post I made before realizing this.

Atmel publish an excellent application note on this subject that 
gives very similar advice to David regarding decoupling of power and 
ground. There are diagrams.

Finally, though David's methods are needed for high-speed 
microprocessors, etc., for an MCU with a 16 MHz crystal it may be 
sufficient to flood and grid the ground without identifying and 
isolating individual return paths. Exceptions: critical applications 
such as medical equipment, equipment for very harsh EMI environments 
such as power plants or automobiles, integrated equipment with 
sensitive (e.g. analog) or noisy (e.g. relay) circuits on the same 
board as the MCU. In those cases, follow David's advice exactly.

Graham.