19 May
2008
19 May
'08
1:35 p.m.
Date: Mon, 19 May 2008 13:27:51 +0000
From: Ethan Dicks
I still build a lot of hobby projects with GALs (like
PALs, but
with much more flexible input and output configurations) - I
don't think I've built a Spare Time Gizmos product yet that didn't
have at least one 16V8 or 22V10. Gate Arrays might be handy for
larger projects, but you can still pack a *lot* into a 20 or 24-pin
GAL.
If someone were just starting out with GAL/PALs, wouldn't PEEL be the
best choice rather than fuse-programmed devices? At least you'd get
a second chance if you flubbed your first try--and they're basically
the same packaging.
Cheers,
Chuck
19 May
19 May
1:40 p.m.
Chuck Guzis wrote:
If someone were just starting out with GAL/PALs,
wouldn't PEEL be the
best choice rather than fuse-programmed devices? At least you'd get
a second chance if you flubbed your first try--and they're basically
the same packaging.
But the original PAL's were so simple, that the logic equations
could almost be done by hand.
Cheers,
Chuck
2:08 p.m.
Chuck Guzis wrote:
...
If someone were just starting out with GAL/PALs,
wouldn't PEEL be the
best choice rather than fuse-programmed devices? At least you'd get
a second chance if you flubbed your first try--and they're basically
the same packaging.
22V10's & 16V8's are electrically erasable and reprogrammable. retry as
many times as you'd like. I'm sure there is some limit on the number of
reprogram cycles, but it is bound to be far more than the number of
insertion/removal cycles the pins would put up with.
Picking up other pieces of this thread, I started using PALASM in 1985,
and I was the one who ported the FORTRAN program to the BTI 8000
computer we were using. Saying it essentially works at the fuse level
is only half the story. Yes, one can have very fine control of things,
but PALASM got smarter as the years went by, and it could do logic
minimization and mapping of state machines to logic just fine.
2:30 p.m.
Jim Battle wrote:
Chuck Guzis wrote:
...
Clarifying a bit, since someone will nitpick me... I'm sure there are
single use 220V10s around, but all the GAL22V10s and GAL16V8's I ever
used were reprogrammable.
If someone were just starting out with GAL/PALs,
wouldn't PEEL be the
best choice rather than fuse-programmed devices? At least you'd get a
second chance if you flubbed your first try--and they're basically the
same packaging.
22V10's & 16V8's are electrically erasable and reprogrammable. retry as
many times as you'd like. I'm sure there is some limit on the number of
reprogram cycles, but it is bound to be far more than the number of
insertion/removal cycles the pins would put up with.
3:10 p.m.
bfranchuk at jetnet.ab.ca wrote:
Jim Battle wrote:
PS: THE 25120 WRITE ONLY MEMORY data sheet can be found here.
http://www.national.com/rap/Story/WOMorigin.html
Clarifying a bit, since someone will nitpick me... I'm sure there are
single use 220V10s around, but all the GAL22V10s and GAL16V8's I ever
used were reprogrammable.
Are the 220V's the ones you program with line voltage?... :)
9:02 p.m.
Jim wrote:
22V10's & 16V8's are electrically erasable
and reprogrammable.
Careful there. That's true of the parts with the GAL or PALCE prefixes,
but not necessarily with all 22V10 and 16V8 parts, especially if you
find old stock. The original PAL16V8 and PAL22V10 definitely *were*
one-time-programmable.
Eric
10:40 p.m.
Careful there. That's true of the parts with the
GAL or PALCE prefixes,
but not necessarily with all 22V10 and 16V8 parts, especially if you
find old stock. The original PAL16V8 and PAL22V10 definitely *were*
one-time-programmable.
They weren't. They still are.
:o)
AS
In a very funny day :o)
7:23 p.m.
On Mon, May 19, 2008 at 10:35:14AM -0700, Chuck Guzis wrote:
I didn't explicitly state it, but GALs are also electrically-erasable
(as are PAL-CEs, another similar pin-compatible logic family).
I've even found good deals on burned-once GALs... just erase them and
go.
In small quantities, I see 16V8s for around $1.00-$1.50 each all the
time, and 22V10s for a bit more ($4.00-$5.00, typically). Sometimes
you can get a good bargain on a tube, and I've even pulled parts
Date: Mon, 19
May 2008 13:27:51 +0000
From: Ethan Dicks
I still build a lot of hobby projects with GALs
(like PALs, but
with much more flexible input and output configurations)...
If someone were just starting out with GAL/PALs, wouldn't PEEL be the
best choice rather than fuse-programmed devices? At least you'd get
a second chance if you flubbed your first try--and they're basically
the same packaging. from the occasional board that I've scrapped for
components. GALs
are frequently socketed, making recycling easy.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 19-May-2008 at 23:10 Z
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Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
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