Re: Atari AVG Controller

Clay Cowgill wrote:
>
> > Like I need another project... not. But I need some guidance at least
> > from all you PAL/PIC/GAL people. Since this IC has ram in it, is that
> >the part that is throwing the wrench into putting this onto a basic PAL?
> >What programable IC's would this circuit fit onto? It is such a simple
> >circuit, can it be that hard? I would be interested in getting at least
> >20-25 of them if I could be done somehow.
>
> I went down this path once before. I have the entire thing designed out in
> TTL, and placed and routed on a PCB. Even have parts to build 10 or 20.
> The only gotcha was that the PCB is kinda large to accomodate all the 'LS
> type chips.
>
> My original poll was looking for who was interested and would you want to
> pay $20-25 bucks a pop for them. (The PCB's in low quantity were around
> $12-15 each, so if you add in $3-5 worth of chips and some $$$ for
> time/assembly they were in the $20-25 range.)
>
> The consensus seemed to be that $30 Space Duel boards were relatively easy
> to find and except for a couple people nobody was interested so I didn't
> make any.
>
> That having been said...
>
> Are enough people interested that I could do a run of 40-50 boards? That
> should be enough to keep the price at or under $20 I'd think... (Since it
> then makes sense to buy chips in quantity 100+ which helps costs and the
> number of boards keeps the setup fees down.)
>
> I looked at the CPLD/FPGA angle too. The circuit isn't really complex
> (it's really just 133% of the discrete stuff you see on Tempest to do the
> Vector Address Generator), but it has some wide counters and 12bit wide
> registers (I think four deep) for a stack. The twist was:
>
> Plan A: CPLD only. Maybe do-able with big enough CPLD. Cost wasn't too
> bad-- around $10 for the part, but the bigger CPLD's won't fit inside the
> footprint of a 40 pin dip so the PCB cost still added another $5-7. Have
> to implement design in Synario or some HDL, or Viewlogic. Kinda involved.
>
> Plan B: CPLD + register file chips. ('670s) Cheaper CPLD (for counters,
> muxes, and logic) for around $6, register files added maybe $1, now you
> need a bigger board to hold the extra chips and I/O's might be a problem on
> the CPLD's. Same complications as Plan A for designing the thing.
>
> Plan C: FPGA. Needs an external boot memory, dev. tools not handy, needs
> big PCB because of footprint size, pain in the rear to hand solder. I
> didn't want to deal with it. (singles pricing for the cheapest Xilinx part
> plus a serial configuration memory is about $18 from Digikey-- and I'm not
> sure the design would fit in that part either.)
>
> Plan D: TTL on a big PCB. Easy to implement. Big PCB adds cost, chips
> are relatively cheap though.
>
> For just cranking something out that'll work I liked Plan D. For a cool
> project I liked Plan A. But, I have enough cool projects so I didn't want
> to take on Plan A. The FPGA route might be good if you could get a
> high-enough density FGPA for the Xilinx 4000 series quantity pricing --
> around $3 per chip plus about $.75 for the serial memory.

Thank you much for the very detailed explanation. That is exactly what I
was looking for.
Thank you again for spending so much time looking into this.
        What dimensions does your current PCB require? Even at $20-25 each I
would be interested
in buying about 10 of them right now (Im oh so poor now, I just couldn't
let that proto Major Havoc
get away!). Of course I had dreams of it fitting on a small chip in a
40-pin DIP header! Damn reality! ;-)

Anyone else interested in buying some of these? Im out of space duel
boards.

-- 
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