anyone out there

[Steve Gorkowski]

If gates and flip flops are your game Lattice has a utility to convert logic
drawings to equations  for plds.

Steve

Andrew K. Mattei wrote:

> Bruce Plecan wrote:
> >
> > I'm hoping it's due to the really cleaver guys working onna emulator design,
> > that the guys here at CSH, HQ can build.
>
> Mr. Chatterbox (me) has been busy lately... Trip, parents in town,
> etc...
>
> However, I have spent some time trying to learn about the CPLD as
> discussed in Ludis' email. Unfortunately, I'm having a tough time
> locating a "basic theory of use and operation" guide on PLD's. Back when
> I was in college taking digital design (a mere 8-9 years ago), they
> never even mentioned PAL devices! We did everything with discrete TTL
> chips/gates... And we liked it! Well, sort of. I've spent time on the
> Xilinx site, the Lattice site, and some others, and am coming up dry.
> Unfortunately, it's not part of my "professional job duties" to work on
> this stuff, so I can't effectively do it at work. ;)
>
> The information I've gathered thus far has given me just enough to get
> my imagination running. However, my mental stumbling block kicks in when
> I start thinking about thrashing bits around and filling / retrieving
> addresses. I think about sending the commands (like xFFF, xFFD, xFFC)
> and then sending data to fill addresses. That's where my black box
> fails... :( To create a logical expression based on several inputs, and
> then have those inputs perform different functions later on... OK,
> really basic question. I "assume" some kind of clock is going to be
> connected to the CPLD - and that based on sequential commands (like
> those above), and a certain logical gate layout, we can vary outputs.
> :-/ How, I don't exactly understand. Of course, *it's not the point of
> this list to teach CPLD's*, is it? ;^D
>
> Of course, I have delinquent thoughts on a (shrug...) low tech parallel
> port based dumb (no uC) semi-emulator. I have all the parts for it in my
> junk bin, and it would just be a matter of building it. I say
> semi-emulator because it's not a true "real time" data changer, it's
> almost just a pair of flash chips in parallel with buffers, selectable
> Bank "A" or Bank "B", that you send a binary image (or pieces thereof)
> to. Pretty simple/basic/old stuff. Premise of operation is that you
> could have two different images loaded, switch between the two (manually
> or electronically), have one bank as "experimental", etc... Load time
> wouldn't be too terrible (minute or so?), but advantage would be that
> you wouldn't have to ever go back to an EPROM programmer again. Just
> have a DB-25 cable hanging out of the ECM to plug in to the parallel
> port. I do believe that this deviates from what the original intent of
> the "EPROM Emulator" was for, though. I believe that the "original
> intent" was to have a near-real time changeable data bank...
>
> I know, I just need to get off my arse and actually *do* something on
> this, right? ;^D You see, it's either work on the car downstairs (the
> one I've removed every bolt from), or sit upstairs and solder... Both
> take lots of time. And I'd really like to get that d*mn car rolling
> again... ;)
>
> Cheers!
>
> -Andrew