5 Sep
2007
5 Sep
'07
6:28 p.m.
Ethan Dicks wrote:
Indeed they are. Bob Armstrong is a heavy user of
GALs for the Spare
Time Gizmos line of hobby products. In the case of the Elf 2000, for
example, you can change the logic equations yourself (he provides the
source) and change the memory and/or I/O map - all of the select logic
goes through a GAL, so the memory map is mutable.
Good digital products for sale. I just question his audio amp just
because the better quality parts are more $$$.
If you are designing your own circuits, a 18 or 24-pin
GAL can replace
several square inches of TTL, with the benefit of being able to make
changes later that don't involve cutting traces and adding blue wires.
You lose the ability to poke around in the middle of select circuits,
and to make substantial changes, but it all depends on what your goals
for the project are if that's a worthwhile tradeoff or not. You do
have to start with a GAL programmer, though. Not all hobbyists have
them, so if you make a product to sell, as Bob does, you should
consider selling programmed parts for those that can't burn their own.
That is the downside , the programmer for them.
I suspect 18 pin GAL is a typo. They come in 20 and 24(thin) pin packages.
-ethan