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Re: [N8VEM-S100:1921] S-100 boards in work

Hi Pete!  Thanks!  Well, this is a bit complicated.  The S-100 uPD7220 GDC is essentially an S-100 version of the ECB uPD7220 GDC board.  That design works for sure on the N8VEM ECB system.  It was ported "as is" to an S-100 bus interface reusing circuitry from the S-100 IDE V2 since they have a similar interface.

However the board is kind of outside the normal channel of S-100 development.  It has not gone through the usual prototype build and test phase other boards have done.  If there is sufficient interest in the board it would make sense to get some prototype boards and have a small team (3 to 4 builders) do an initial build and test to verify the design works.

I think the risk of a non-fixable completely dead board (FUBAR) is fairly low since there is pretty minimal "coupling" between the uPD7220 GDC and the S-100 bus (IO port only, RD*, WR*, CS*, etc).  Also the ECB uPD7220 demonstrated the basic principle is sound.  It relies on all tried and true components and circuits from other boards which really minimizes the risk.

We could easily go to prototype build and test with this design.  The prototype board is completely done except for getting a batch of boards from www.33each.com and I have schematic and PCB layout if anyone wants to see the design.  All we need is a build and test team and we are ready.  Also the 4 prototype boards will cost around $150 so if anyone wants to chip in on them that would be great too.

Please let's discuss!  Thanks and have a nice day!

Andrew Lynch

On Mon, 9/23/13, Pete Plank <sgi.ne...@gmail.com> wrote:

 Subject: Re: [N8VEM-S100:1921] S-100 boards in work
 To: n8vem...@googlegroups.com
 Date: Monday, September 23, 2013, 3:58 AM
 On Sep 22, 2013, at 7:47 AM, Andrew Lynch <lyn...@yahoo.com>
 uPD7220:  Ready to go to prototype but there doesn’t
 seem to be much interest in this board.
 I was actually looking forward to this one. No
 chance of it being made?
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