RE: Cat Box

On Tue, 21 Jul 1998, Clay Cowgill wrote:

> I was going to ask that... What are your logic requirements? Is it
> mostly combinatorial or clocked register stuff or do you need lots of
> memory elements?

        Lots of memory elements. Off the top of my head, there is a
16-bit latch, an 8-bit latch, a 16-bit counter, a 16-bit shift
register, and I think maybe another 16-bit latch and another 8-bit
latch. Another counter or two, but not necessarily 16-bit.

        Not much other logic. The counters can be done with T
flip-flops, and the MACH series stuff can configure its macrocells
that way. Most of the outputs are tri-stated, so there is some
tri-state enable logic. Block diagram wise, there's not much too it,
really.

> True. I dunno though-- a MACH211SP gives you 64 macrocells and 34
> I/O's. It's incircuit programmable and only $3.70 a pop in singles.
> Three of those guys are only around $12, and since you could buy larger
> quantity of the same part you'd probably get in the $3.00 range pretty
> quick...

        I suppose it's possible to "bit-slice" the design into some of
those...

> Good point. For $30 a chip I'd be inclined to just use the 435,
> personally. Not like there's going to be ten-thousand people all
> wanting Catbox-replacements... If the 435 was really $65 and you could
> use a few 211's instead for 20% the cost I'd have to say go for the
> 211's.
>
> (I've got a design at work here that's using two 22v10's instead of a
> Lattice 1016 or Mach111 because the 22V10's are cheaper. You pay more
> for the PCB area, and you pay more for placement and test, but the delta
> is still enough to justify splitting the design...)

        Like I said, we'll see how it pans out...The Synario tool
doing automatic partitioning is making that more palatable to me.

Joe
Received on Tue Jul 21 12:05:26 1998