A lot of these designs want to be pushed a little for clock rate, and It feels really odd sticking a slow part like a 'ls682 in my critical address decode path, especially when it's cascaded like in the rom/ram board. sticking 35 ns memory in there and then blowing another 30 ns just to decode the address lines to get a chip select will keep you from running at 10mhz without wait states. an 'F520 will do the same job in half the time, if you ground the unused p>q output; so all my '520s in '682 sockets have pin 1 lifted and wired to ground with a scrap of kynar. and my chip selects come out 10ns earlier.
it this just a whine? I really dislike the '682, since you can't get any faster parts with this pinout that have the internal pullup.
--curt, on a quest for a 12mhz s100 0WS z80.