[Coco] make-do ROM Paks

[Darren A.]

>From: Roger Taylor
>Subject: Re: [Coco] make-do ROM Paks
>Date: Sun, 16 Sep 2007 14:20:15 -0500
>
>
>
>Hopefully there is a direct replacement (pins and voltage) for the 24-pin 
>ROM types that are used in our old CoCo game paks.

That would be the 68766 (or 68764).


>The board design is what I'm wanting to use, with a 24-pin socket, and some 
>kind of 24-pin 8K EPROM that doesn't require 25 volts to operate or 
>program.

I don't know of any 24-pin 8K EPROM other than the 68766/64. These do 
however require 25 volts to program.


>The idea is to clone a CoCo ROM Pak board, socket it, insert an 8K EPROM, 
>*but*.... at this point the way things are looking, a 4K EPROM will 
>probably do just fine.
>
>I can code pretty tight and can do serious things in 4K.  If a 2732 won't 
>work in an old socketed ROM Pak, then I'll probably need to get a mess of 
>boards made for the common 2764.  I'm not seeking a ROM adapter for this 
>kind of project, and I'm aware of Cloud-9's great product.
>

If you end up needing to get a 'mess of boards' made, why not just go with a 
design that uses a 28-pin socket to accept 2764/27128/27256/27512 EPROMS?  I 
have already created a prototype layout for such a board using the 
ExpressPCB software. I can send you the layout file if you like. You can 
view an image of the layout at:

http://www.coco3.com/users/DarrenA/CoCoPak.gif

The layout has some jumper pads for configuring the A13 address line and 
Auto-Start. The board dimensions have been minimized to reduce cost, but it 
could easily be enlarged or reconfigured so that it could be mounted in a 
case. The ExpressPCB price quote to have 10 of these boards produced is 
$97.65 including shipping, 100 boards would be $396.84. These would NOT have 
gold contacts on the connector.

Darren

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