[Coco] Blank PCB for EPROM-Based Cartridge

[Al Hartman]

This is most excellent!!!

This is exactly how projects like the NV8EM and the XT-IDE board are done.

I hope we can add more projects to the list, like a disk controller (a guy 
in Spain makes a Disk Controller for the Dragon - I gotta get one for my 
Dragon!), an 80 Column Card (as is being discussed in another thread), maybe 
some kind of sound card (using a SID chip, or just compatible with the 
Orch-90?).

When I worked at Zebra Systems, we made all sorts of neat, inexpensive 
things for the Timex Computers. That was fun!

-[ Al ]-

-----Original Message----- 
From: Mark J. Blair


On Sep 26, 2013, at 07:19 , billg999 at cs.uofs.edu wrote:
> Assuming a reasonable price, I would be interested in a number of them.
> And, I assume the more made in a run the cheaper the run becomes, right?

Uh-oh, it looks like we have multiple hardware guys named Mark here now! 
Feel free to call me by my ham radio callsign (NF6X) to avoid confusion. :)

Ok, regarding my EPROM board that Al talked me into: It's just a simple 
board to let folks use whatever old EPROMs that have laying about, and I 
don't see it as being much of a competitor to a fancier flash-based board 
once that's out of the gate.

I don't expect to make any money off of this simple EPROM board, and I'm 
releasing the files under GPLv3. I'm using this simple design as an excuse 
to try out a small-run PCB shop called OSHpark, in particular because they 
provide ENIG surface finish. In other words, gold plating, which is nice for 
the card edge fingers. They also have a feature on their web site called 
"Shared Projects" which is geared towards this kind of project in which I 
just want to give it all away and be done with it. Once I verify that the 
thing actually works, I'll put the design in their Shared Projects area so 
anybody can order up the bare boards without involving me at all. Their 
pricing for these small runs is $5 per square inch for 3 boards. So, 
ordering would be in multiples of 3 boards, and each bare 2.1"x1.75" board 
would end up costing a little over $6. Boards would have purple solder mask, 
gold surface finish, white silkscreen on both sides, and plated holes. 
Beveling the card edge would b
e a job for the buyer.

Maybe I'll make a for-profit CoCo-related product someday, but this 
particular project is a freebie for the community that I'm using to test out 
this PCB fab that I've been interested in. I expect it'll have some limited 
interest for a while, then fade into obscurity once the Cloud9 flash boards 
(?) are on the market.

I'm changing the board to add a couple of jumpers to allow up to 27512 
EPROMs to be used, by the way. I'll be pushing the revised files to GitHub 
sometime within the next day or three, and then I'll fab up a batch of 3 
boards for me to test out. If they work right, then I'll push it out to the 
OHSpark shared projects page, and y'all will be on your own to build them! 
:)

Here's the OSHpark Shared Projects page for anybody who's curious:

http://oshpark.com/shared_projects


-- 
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/


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