RE: Multi cabinet control panel routing

I checked arrow America and they list the ispGDX for 15.80 each in singles. 
I can swing that, though it is a 100 pin TQFP and would require a board to
be made to connect it up.  This part has 80 i/o pins and a 5ns response
time.  Would be WAY overkill but it is pretty much a 1 chip solution. 

Yeah, the lack of 74xx type functions in Synario had me pretty baffled
for a while there too.  You can either build them yourself from raw
gates (which I did for most of my stuff), or model them in ABEL.  The
main "gotcha" is that the concept of an OC or tri-state doesn't really
exist inside the programmable chips.  You have to kinda re-think the
design to fit the architecture.  (That's what took the longest when
trying to adapt the TTL implementations of the Pacman daughtercards --
you can't just have registers hanging on the same wire that are
tri-stated when not active.)

Do you know if the 74xx type stuff is available in a library or in the
"full" version of the product?  I am pretty familiar with that kind of logic
and getting over my head doing much else.

Well, I think Zonn's on the right track.  I'd look at something like the
Atmel AT90S4414 uController and read the inputs as a matrix.  The 4414
has 32 lines of IO, built-in flash and SRAM, etc.  Use one port to scan
your "inputs" as a switch matrix, and then use 20 dedicated output lines
for you parallel presentation to the game interface.  The AVR (Atmel)
ports will sink 20mA each.  (Not like a PC keyboard uses 105 lines of
I/O.  I bet you there's a PIC appnote somewhere that shows how to read a
switch matrix with just a few IO lines...)

Well I guess I can check this route out.  Though I don't know if I want to
deal with the external diodes required to turn it into a matrix, starts to
sound too much like a pinball :)

The Atmel development kit with a circuitboard/programmer and software
(assembler, programmer, simulator) is only $49.  At the AT90S4414 in
singles is only about $6.75 (sub $5 in 100's from distribution).  And
you can just program it in assembly, or IAR has a demo version of their
C compiler you can use for free for up to 256 bytes of object code (or
something like that)...

HMMM.  Well it's something else to look at.  I guess after 3 years a few
more weeks of learning won't kill me.  :)
 
David
 
Received on Wed Dec 2 19:54:40 1998