This is my first project designing a PCB, and it is a doosy. The project is a BASIC stamp microcontroller to drive 72 sets of LEDs. I'm using 8 outputs from the stamp as inputs to 9 latches. 4 more outputs from the stamp are run to a 4 to 16 demultiplexer, which is used to select an individual latch to set it's output. Do I need to terminate the 8 output bus to ground through resistors? The bus runs for approximately 4 inches with a 5v signal and less than a 20mA load. It will be operating no higher than 20kHz, so my gut says no, but i figured I would ask anyway.

Attached is the sch file from ExpressSCH just in case I lot you with my description.

 

I cannot open the .sch file using eagle .
Am I missing something?

 

I cannot open the .sch file using eagle .
Am I missing something?

That is because it's an ExpressSCH file, not an Eagle file.
http://www.expresspcb.com/ExpressPCBHtm/Free_cad_software.htm

 

To answer the question--it's a short line, and slow signals. So this is one place where you can skip the terminations.

 

Express....Did not use it before.
And it's free too. Coooooool.

 

As others said short distance does not need termination.
What kinda environment are planning to have it in?

 

This is going to be used like a consumer level product, so no extreme temperatures nor moisture. It's actually going into a beer pong table. Just have to make sure spills on the table won't get the electronics.

 

I meant noise. RF interference

 

This is going to be used like a consumer level product, so no extreme temperatures nor moisture. It's actually going into a beer pong table. Just have to make sure spills on the table won't get the electronics.

Small spills can become large ones in drinking games, I'd pot it in clear polyurethane or acrylic resin. The stuff is cheap enough and available from most large hobby shops, they use it to make those decorative paperweights out of.