AVR-Chat

At 06:44 PM 7/10/2004 -0700, jay marante wrote:

>thank you, sir...
> 
>i've read about "gridding" the ground trace. is this right? i says that there should be grid for the ground trace through out the board, maybe horizontal on the bottom and vertical on the top layer or vice versa. then just connect a via if i go from horizontal to vertical / vertical to horizontal.

Gridding or planing is ok, but don't let the plane try to do your work for you. Handle the ground returns that you know are noisy, yourself.

> 
>on your rule #4, what do you exactly mean by "Put the bypass at the client's ground pin. Make this the connection point to system ground. Route a fat track from the client's VCC pin(s) to the cap. Route a skinny track from the cap to system VCC"

The "client" would be the chip that's being fed from the power supply. 
The bypass cap should be local to that client, and the tracks arrainged to serve that client.

> what i have in mind is that i'll have bigger tracks for system VCC and GND and when i connect the IC's ground and VCC, i'll have a bit smaller track than the system's VCC and GND.

Well, as you go back toward the power supply, the current on the tracks rises, but for logic and such, the current is so low that it almost doesn't matter.