> Jeff Otterson/N1KDO <otterson@MINDSPRING.COM> wrote:
> > Maybe he can use a GAL do to his address decoding, and read-protect the
> GAL.
> > That method has been used by more than one vendor that I am aware of...
>
> Protected GALs can be easy copied without reading the devices' fuse
> map. It's especially easy in case of an address decoder, where no latches
> are used and there is one-to-one assignment between input and output
> values.

Reading out a protected GAL in which there are no latches is trivial; on
GALs with latches things may be harder but if no latches are buried it's
still easy.  Reading out a GAL with buried latches may be a little bit
difficult, but since at most 9 latches may be buried in a 22V10 that does
anything useful I would not expect this to be any more than 512 times as
hard as reading one with no buried latches (which I would expect to be
fully automatic).