[Coco] An 8-Slot Multi-Pak Design for my Color Computer Friends

[jdaggett at gate.net]

First 

A huge mistake in not buffering the data bus on the main board. If you are running a stock 
Coco3, you do run the risk of damaging the MC6809E and the HD6309E if the board 
becomes detached while powered up. 

Second

why the dip switches on the Control and clock lines. A wrong setting on the dip switches and 
you have a nonfunctioning board that can lead to frustration.

Third

What is the function of Q1?

Fourth

Your ground plane on the top and bottom are basically floating planes that are tied at but just 
a few spots. You have all your locic tied to GND1 and then this large plane on both sides is 
GND. You also have fingers that are floating that is bad for noise immunity. Either use one 
ground or tie them in a star pattern and eliminate the floating fingers. 

just a few things I see wrong or bothersome. 

By the way I have a degree in Electrical Engineering and have 23 yrs experience in PC layout 
and design of portable electronics. SO these questions do come from someone that has 
experience and questions about the design. 

james 
On 3 Jul 2010 at 18:12, Little John (GIMEchip.com) wrote:

> This is my latest project, designed just for you guys and the readers of CoCo3.com. I worked on this for about 9 hours when my internet was off. Hopefully it will be of some use to some of you.
> 
> It is taking a lot longer to do the write up than it did to complete the design, but I have posted Part 1 (of 2) here:
> http://www.coco3.com/community/2010/07/this-is-part-1-of-2-of-an-8-slot-mpi-multi-pak-interface-design-for-my-friends-at-coco3-com-andor-the-maltedmedia-list-members-from-your-friend-johngimechip-com
> 
> Let me know if you spot any potential problems. I'll get part two typed up and posted by tomorrow.
> 
> Enjoy. Let me know if you find any errors in my design. I'll fix any that crop up.
> 
> Your Friend - Lil' John
> 
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