VECTORLIST - The Mailing List For The Technical Discussion of Vector-Based Arcade Games

November_1997
Re: Development stuff...


From: Clay Cowgill ( )
Date: Wed Nov 26 1997 - 16:16:15 CST


>Cool -- sign me up for a couple. Can I ask for a few things on it?

Sounds good... I'm trolling for input...

>Lots of +5 and GND connect area. Seems like some of the boards I've been
>working on just require a lot (multiboard sets, etc..) Currently I get this
>growing "chain" of jumpers..

Yep. I agree there. It's part of my reason for doing this-- thin jumper
wires don't carry enough current to really power big boardsets like Pole
Position, I,Robot, etc...

>3 audio amps (I've never seen a game need over three -- gorf/wizofwor/etc
>do need three though -- left/right/voice)

Ah. Ok, hadn't thought of that. I can either combine them into a single
channel (it *is* just a tester :), or put down three amps. I'm planning on
using the little LM386 since we use millions of 'em in our modems and
they're really cheap for me to get. I could even put a little speaker on
the board actually...

>Inputs for CSYNC, VSYNC and HSYNC (combine V&H) and also have an inverter
>for the sync. I use a '86 as I recall to combine, and an '04 to invert
>in my little "does everything" video board. I've just got 2 switches on
>the board, one for sync select (C, or H+V) and one for invert.

You can actually do all that in one 74LS86. One switch sets output
polarity with the last XOR gate, the other gates combine the H and Vsync.
I did this for my monitor tester...

>It would be cool to allow a little plug in module to invert the RGB too
>(for those that might have to test nintendo stuff -- paul kahler had a nice
>little analog inverter circuit).

That's easy enough too. A pair of LF353's will work fine. (Another part
we buy in the millions, so they're cheap... :-)

>I know -- we take a cool little project and make it grow.

I don't think that's too much to ask. I need to think about the best way
to do it now is all...

>Have you ever seen a PAT9000? (an Atari test piece). VERY impressive.
>(and as my old roommate would say "Lots of switches and lights!")

I've never seen one. :-( Anybody have pictures?

-Clay

Clayton N. Cowgill Engineering Manager
_______________________________________________________________________
/\ Diamond Multimedia Systems, Inc.
\/ Communications Division http://www.supra.com/


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