Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!rutgers!cbmvax!grr
From: grr@cbmvax.UUCP
Newsgroups: sci.electronics,comp.unix.wizards
Subject: Re: time of year clock chips
Message-ID: <1934@cbmvax.cbmvax.cbm.UUCP>
Date: Tue, 26-May-87 21:20:58 EDT
Article-I.D.: cbmvax.1934
Posted: Tue May 26 21:20:58 1987
Date-Received: Thu, 28-May-87 04:17:22 EDT
References: <16819@amdcad.AMD.COM>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 28
Xref: utgpu sci.electronics:667 comp.unix.wizards:2262

In article <16819@amdcad.AMD.COM> phil@amdcad.AMD.COM (Phil Ngai) writes:
> 
> I'm designing a CPU board and wondered if anyone could recommend a
> time of year clock chip. Flames about particularly bad or hard to
> program time of year clock chips are welcome too. 
> 
> Phil Ngai, {ucbvax,decwrl,allegra}!amdcad!phil or amdcad!phil@decwrl.dec.com

The OKI58321 is the low cost leader, but is super slow and needs to be accessed
through some kind of parallel port.

The OKI6242B can interface to a normal microcomputer bus running at normal, but
not blazing speeds and is a good compromise.

Ricoh makes a chip much like the 6242 that includes ~15 bytes of static RAM,
useful for saving configuration or boot up data.

These chips are also available as modules, with battery and/or crystal included,
if the additional cost is a good trade off.

There are lots of other chips available.  Watch out for vapor chips and read
the fine print on accessing, battery backup/voltage requirements and glitch/
latchup protection...

-- 
George Robbins - now working for,	uucp: {ihnp4|seismo|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)