GALs and PALs (was Re: [Free] Old Data Books (Australia))
bfranchuk at jetnet.ab.ca
Wed Sep 5 12:28:02 CDT 2007
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.
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