ISTR that the programming interface for PLL chips is the three wire serial
form, with a static clock. you _COULD_ drive it with
three switches, but you'd have to at least debounce them -
RS flip-flop from NAND ususally being the simplest way.

Might be interesting to derive a driving circuit from
el-bug principles!

Scott Dorsey wrote in message
...
All of the AD synthesizers I have seen have a microprocessor interface,
where they basically memory-map into a processor. I'd rather have
something
I can directly address.
I could probably pull out a 68HC11 to control the thing if I absolutely
had
to, but I'd rather have something I can just latch a BCD input into.
--scott