RE: Spinner Replacement for Omega Race

From: Clay Cowgill <c.cowgill_at_comcast.net>
Date: Fri Aug 01 2008 - 04:34:20 EDT

> Oh you and your AVRs :-P !!! What fun is that :-P (just kidding).

Hey!!! Don't you have an LCD controller you should be working on? Slacker.
;-)

(P.S. Have you seen James' 6802/Williams Sound board emulator running on a
ATmega8? That impresses the hell out of me for some reason. :-)

> A microcontroller is going to give you a lot more
> flexibility....but the
> function seems so simple that a PLD would be so much
> straightforward in
> this case....I guess its designer preference :-)!

Yeah... I was just thinking that it might be easier to have a micro with
"all" the possible program behaviour on it and just select it with a button
and some LED's or something. Store the "personality" byte in the on-die
EEPROM and just be soft-settable. (I was under the impression the CPLD was
the 9536 though too, so I was thinking "hmmm, maybe not enough resources for
everything". '72 would probably be fine even with G-80 spinner support...)

> Just curious Bill,
> what is your resource utilization in the PLD? I see you're
> using a 72
> macrocell device....I kind of think a 36 macrocell device would work
> here just to save you a few cents.

FWIW, I fit two channels of quadrature decoder with like ~8 bits of pulse
accumulator per channel (automatically clearing after a read) in a 9536 and
still had room for some combinatorial stuff for video signals and some
simple SPI interfacing. In a 9572 version I had four channels (two
trackballs) and a full JAMMA+ input signal set (~26ish inputs) plus video
sync stuff and some security functions. Ran out of pins before macrocells!
Amazing what you can pack into those really.
 
> This is a dumb idea, but you can implement a simple
> sigma-delta DAC in a
> PLD/FPGA....I wonder how difficult it might be to make an optical
> solution for Star Wars / Spy Hunter controllers...I hate those pots.
> Aren't they up to $15 a piece for those industrial ones? I
> understand
> that once you install them for home use, you'll never need
> them again,
> but I am sure those are going to be harder to source someday soon.

Interesting... I wonder if the step resolution on low cost encoders would
be enough? Star Wars' software would smooth out steps anyway, but it might
be hard to target specific points on screen if you only had ~64 pulses per
revolution or something (since the yoke would probably only exercise <90
degrees of that on the "vertical"). A long while back a local surplus place
here had a bunch of (Bournes?) encoders that were pot-sized/shaped and had
256 steps per revolution. Rated for 1000's of RPM too-- sold for like
$250/ea when new. They still wanted $30/ea so I think I only ever bought
one or two. Would have been perfect for that application though.

-Clay

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Received on Fri Aug 1 04:36:25 2008

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