Lattice & GAL questions...

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2 total messages Started by James MacPhail Mon, 28 Dec 1992 02:37

#610

Author: James MacPhail
Date: Mon, 28 Dec 1992 02:37

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Is there a Lattice Semiconductor engineer or e-mail address
here-abouts? I'm looking for the answers to the following:

What's the difference between a GAL16V8 and a GAL16V8A?

What are the product term disable fuses useful for?
(Other than the obvious... why are these in the architecture?
do they alter the speed/power dissipation?)

Why is the architecture configuration still accessible after
programming the security fuse? It seems to me that this saves
a few hours for the buggers off-shore (or on-shore!) that are going
to reverse engineer my product!

And finally... why is the 16V8 so much cheaper than the 22V10? 
A factor of two seems reasonable to me, but 4-6x seems excessive.
I've been putting in two 16V8s instead of a 22V10 in most cases,
and am happy to continue to do so, but it seems to me that there
would be more profit for Lattice if the 22V10 came down some.

Thanks for your time...

James MacPhail  jmacphai@cue.bc.ca  james@mirg2.phy.queensu.ca

Re: Lattice & GAL questions...

#703

Author: Alex Novickis
Date: Mon, 04 Jan 1993 23:46

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In article <1992Dec28.023739.9176@softwords.bc.ca> jmacphai@cue.bc.ca (James MacPhail) writes:
>Is there a Lattice Semiconductor engineer or e-mail address
>here-abouts? I'm looking for the answers to the following:
>
>What's the difference between a GAL16V8 and a GAL16V8A?
>
16v8  = 1st design
16v8a = product terms added to allow feedback paths in simple mode
16v8b = added pullups to all pins
16v8A-QP = quarter power 16v8a design

>What are the product term disable fuses useful for?
>(Other than the obvious... why are these in the architecture?
>do they alter the speed/power dissipation?)
>
YES!! They alter the power usage. Bingo. However I have yet to see a 
programmer & software package that allows you to set these. Apparently
the bottleneck is in the programmer, but I can't see why exactly.

>Why is the architecture configuration still accessible after
>programming the security fuse? It seems to me that this saves
>a few hours for the buggers off-shore (or on-shore!) that are going
>to reverse engineer my product!
Modern programmers have built-in algorithms to detect what
if the type of device you plugged-in matches the device you selected.
This is sometimes important to prevent damage to both device and
programmer.

The only time I can see this to be of significance is when you include
test vectors in your download to the programmer.

>And finally... why is the 16V8 so much cheaper than the 22V10? 
>A factor of two seems reasonable to me, but 4-6x seems excessive.
>I've been putting in two 16V8s instead of a 22V10 in most cases,
>and am happy to continue to do so, but it seems to me that there
>would be more profit for Lattice if the 22V10 came down some.
16V8 production volumes are much higher.

>
>Thanks for your time...
>
>James MacPhail  jmacphai@cue.bc.ca  james@mirg2.phy.queensu.ca

Call 1-800-fast-gal for GAL info. They usually have an engineer
type you can talk to within minutes.

Strangely, I just knew most of thes of the top of my head, and I'm
*not* associated with lattice.


-- 
Alex P. Novickis, Real Time systems demi-guru.  (W)   408-862-4541
ALINK:alex.n                                    (H)   415-691-0657
UUCP:{amdahl,claris,pyramid,sun,decwrl,well,ubvax,ames}!apn@apple.com,apn@nonvon
"I think... I think it's in my basement. Let me go upstairs and check"-Escher.

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