[Coco] need a mini 6551 RS-232 pak layout

Roger Taylor operator at coco3.com
Thu Jan 15 23:10:18 EST 2009


I'm looking for someone who can help finsish designing the schematic 
and board layout for a mini RS-232 pak based on the rather simple 
schematics for the CoCoPro! RS-232 Pak.  As some know, this is 
nothing more than the schematics for the DC Modek Pak but with the 
phone modem circuitry removed.  It's just a 6551 and ROM mapped to 
the expansion port pins.  My version has an EPROM instead of the 
ROM.  There's 4 chips and the board fits in a standard game pak 
case.  The board is already designed to fit any game pak and also a 
new case I'm looking at.  So, the mini RS-232 pak layout has to fit 
on this board.  I've already got the chips layed out similar to the 
DC Modem Pak's format but I'm having trouble with the trace 
routing.  Maybe that's because I'm not an expert at such.

The software needed is free, called ExpressSCH and ExpressPCB.  If 
you can use ExpressSCH/ExpressPCB and are good with design and the 
6551, please submit a quote for what you think it's worth for you to 
finish laying out this board and test all the connections "on paper", 
etc.  6551, 2764/27128 EPROM, 74LS04, 74LS133.. that's about 
it.  I'll work with you to help get this done so I can send off for 4 
sample boards as quick as possible.  Give me an idea of what you'll 
need or not need.

I've got the base layout files, and about 75% of the schematic is 
drawn and some of the net connections are defined which helps 
ExpressPCB reveal what pins need to be connected with traces, etc.
-- 
Roger Taylor

http://www.wordofthedayonline.com




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