>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
_______________________________________________________________________
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\/ Communications Division http://www.supra.com/
