Date   : Thu, 28 Dec 1989 15:03:18 GMT
From   : att!laidbak!luke@ucbvax.Berkeley.EDU (Luke Weerts)
Subject: CLOCK/CALENDAR FOR CP/M

In article <25398@cup.portal.com> Jhanos@cup.portal.com (JONATHAN E HAWES)
writes:
>Greetings,
> 
>Again I address this thread to ask if there is anyone who knows of the
>things I have been reading about. This past weekend I was reading over
>some back issues of MicroCornucopia, and two articles came immediately
>to my attention.
> 
>     1 - First was the article by Mitchell Mlinar about the building
>         of a hardware clock for the Xerox 820-II.(MicroC, Oct '84)
>         [ Stuff deleted ]

If you don't find the part you need, try buying the No Slot Clock. 
Basically it is a clock/calendar on a 28 pin rom socket.  Its
advertised in all the computer magazines for Apples and PC-compatibles
but I found it works great on my Kaypro II (pre-'83) even though the
Kaypro's socketed roms are 24 pin.  Since the software is not CP/M
you'd have to write your own software to access the clock.  This took me
4 or 5 hours in assembler.  Their documentation provides the interface
specs to the clock.  It plugs into any rom socket and the rom plugs into
the top of clock. (Putting it into a 24-pin socket requires one jumper.)
The clock passes all signals to the rom until a 64 bit sequence "unlocks"
the clock, at which time the clock can be read or written.
The cost?  Mine cost $45 a couple of years ago but I think I've seen them
since in the $35 - $38 range.

Luke Weerts

Hardware Handicap -- Software Savant