Jhanos@cup.portal.com (JONATHAN E HAWES) (12/27/89)
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)
In the article, he describes this clock circuit and how it
plugs into the Parallel printer port on the motherboard.
Now, since I have a BBS operating on a Xerox 820-II, and
seeing how I don't have an adequate way keep a battery back-
up clock, I tried assembling the parts for this device.
Unfortunately, I can't seem to find the 18 pin clock chip
described in the article. Mitch asks for a MSM5832 clock/
calendar chip. Well.... having called all over the nation
looking for one, I still can't seem to find one. Is there
source for these, or is their a modification to allow the use
either the 24 pin or 16 pin clock chips from National Semi-
conductor. I figure the schematic has been modified over the
years, but surely someone out there knows how to build one,
and would be willing to explain it to this ingnorant sysop.
2 - The other article that caught my eye was from the April '84
issue, that being an evaluation by Clarence Peckham of the
Xerox 820-II and the LA Software Dynadisk, a 256k RAM array.
Is there anyone out there who remembers these things?
{ Dang! asking like that makes me feel ancient! )
Any help will be greatly appreciated, and muchly welcomed! :)
Jonathan Hawesjim@mmsac.UUCP (Jim Lips Earl) (12/28/89)
Try JAMECO ELECTRONICS for that clock chip. Their catalog shows a
MSM5832RS 18 pin Microprocessor Real Time Clock/Calendar for $2.95.
Address:
Jameco Electronics
1355 Belmont, CA 94002
(415) 592-8097
I've had good luck with these guys, and recommend them highly. They
ship very fast.
--
Jim "Lips" Earl UUCP: ucbvax!ucdavis!csusac!mmsac!jim
KB6KCP INTERNET: mmsac!jim@csusac.csus.edu
=======================================================================
The opinions stated herein are all mine.jmasters@pcocd2.intel.com (Justin Masters ~) (12/28/89)
In article <2950@mmsac.UUCP> jim@mmsac.UUCP (Jim Lips Earl) writes:
+Try JAMECO ELECTRONICS for that clock chip. Their catalog shows a
+MSM5832RS 18 pin Microprocessor Real Time Clock/Calendar for $2.95.
+Address:
+Jameco Electronics
+1355 Belmont, CA 94002
+(415) 592-8097
+
+I've had good luck with these guys, and recommend them highly. They
+ship very fast.
Yeah, he brags about 'em all the time. :)
If they don't carry them (I noticed you said you tried all over the country),
you might want to find out what kind of inputs/outputs are on that chip, and
if it's easy to swap in another chip, you might want to get an MM58274 (harder
to find) or MM58174. Jim has the '274 running his clock in his computer.
Jim, I still haven't put mine together yet...
+--
+ Jim "Lips" Earl UUCP: ucbvax!ucdavis!csusac!mmsac!jim
+ KB6KCP INTERNET: mmsac!jim@csusac.csus.edu
+ =======================================================================
+ The opinions stated herein are all mine.
-----------------------------------------------------------------------------
Fireman to homeowner: At one point we | Justin Masters
decided to fight fire with fire... |
basically your house burned even faster. | jmasters@fmdgr1.intel.comluke@i88.isc.com (Luke Weerts) (12/28/89)
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