Re: avg asic

>is there a small footprint Lattice part that
>would fit into a 40pin outline?

I'll have to re-check. They might have an SSOP package for those that
MIGHT fit in there. It's entirely possible that I was only looking at the
PLCC packages since I *REALLY* didn't want to hand-solder anything smaller.

>does it use all 40 pins of the package?

Pretty close as I recall. I remember thinking that it might work in a
44pin PLCC part if the macrocell count was high enough. You know... I
could do something like:

 +---------+--------+---------+
 | o o o o | | o o o o |
 | | | |
 | | | |<-- Not a band-aid. A 40 pin IC sized PCB with
 | o o o o | | o o o o | a square PLCC in the middle going "over" both
 +---------+--------+---------+ rows of 40 pin DIP pins...

And just clip off the I/O pins that would short out to the through-hole DIP
pins. Like:

    | | | | | | | | | | |
  --+-------------------+--
    + + <-- snipped off pins
    + +
  --+ +--
  --+ +--
  --+ +--
  --+ +--
  --+ +--
    + +
    + +
  --+-------------------+--
    | | | | | | | | | | |

I'd lose some I/O's. (probably 4-8 depending on the package and lead
spacing), but at least it would sit "over" the DIP.

It's mucho more expensive to make a non-rectangular board like:

           +---------+
+---------/ \---------+
| |
| |
| |
| |
+---------\ /---------+
           +---------+

(Have to pay for router time, which is usually only available on a more
"production" level pay scale for the PCB's. And the boards are usually too
small for the "affordable" manufacturer's to do.)

-Clay

Clayton N. Cowgill Engineering Manager
_______________________________________________________________________
/\ Diamond Multimedia Systems, Inc. clay@supra.com
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Received on Wed Jan 7 18:00:42 1998