On Mon, May 19, 2008 at 08:47:44AM -0400, Tim Shoppa wrote:
Since you mentioned it... and since this IS
classiccmp...
The first version of PALASM I used was back in 1984 or 1985,
and it ran on a VAX and a PDP-11. If I recall correctly, it came as Fortran
source code and was from MMI, the big seller (at the time)
of PAL's. The MMI databooks of the era were very good at
convincing old stuck-in-the-mud-types like me that PAL's were
a huge improvement over discrete logic, showing how logic
equations map into blowing diodes, and blowing diodes
in a PAL results in exactly the function you wanted to begin with.
I have similar experience. We had both the FORTRAN version of
PALASM running under VMS 3.6, and I think one of our PAL burners,
one with a stringy floppy, had something similar running on board
(i.e., you could feed it PALASM source over its serial port, not
just JEDEC files).
About the only docs we had in 1984-1985 were MMI databooks and
application notes (like how to build electronic dice, etc.)
It was a long time before I started to understand what I was
reading - I blew hundreds if not thousands of PALs before I
ever had to fiddle with the equations.
As a practical matter, for a modern board, you'd
probably
use gate arrays for all but the most straightforward decoding
to do it really modern.
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.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 19-May-2008 at 13:20 Z
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Ethan.Dicks at
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