How exactly do PAL chips get programmed?

[Brad Parker]

"Teo Zenios" wrote:
>
>What I want to know is are PAL chips somewhat like eprons in getting
>programmed or is there some other process involved?

depends.  old original pals were fuse-link and hence OTP (one time
programmable).  At some point "GALS" came along which could be erased
and reprogrammed (they are more like eeproms in their technology as I
recall).

In most cased you could replace a PAL with a GAL, as long as the speed
of the part was correct.

What's the part?  if it's something like a 16L8 or a 22V10 then you
should have no problem.

It is possible to 'program' a pal such that it can't be read.  If your
pal has had this done you are out of luck.  If it hasn't you should have
not problem reading the contents.

>Does anybody here have any experience with a IIfx running a Tokamac II FX
>upgrade processor?

I actually had one and did some things with it but it was such a long time
ago that I have no recollection, sorry.  I do remember it ran a demo very
quickly (I think it did fractals on the screen).  

I don't remember having to replace a pal, however.  And I used it on a
IIfx.

-brad