Date   : Fri, 16 Mar 1990 20:20:42 GMT
From   : mcsun!unido!balu!tilmann%cosmo.UUCP@uunet.uu.net (Tilmann Reh)
Subject: Need info on 5832 and 58321 clock chips

Hello Ralph,

you have to distinguish between two 58321's :
- the MSM 58321 from OKI is a functional (not pin2pin) replacement of the 5832,
- the RTC 58321 from Seiko-Epson is a direct replacement for MSM 58321, with
  built-in quartz (let XT terminals open).

By the way, if you are designing a new circuit, think about the RTC 72421,
also from Seiko-Epson. It's a newer design, making the RTC registers available
via direct bus connection using 16 I/O (or Memory) addresses. The access time
is 120 ns, which should be small enough for every micro. Quartz included also.
Or have a look at the new chips of Dallas Semiconductor, i.e. DS 1286 or 1287.
These contain RTC with quartz, 50 bytes of NVRAM and the appropriate Lithium
Source for 10 years operation (guaranteed).
The RTC 72421 is housed in a 16-pin-DIP, the DS 1286 comes in a 28 pin and the
DS1287 in a 24 pin DIP case with some height (cause of the battery).

Look at the new chips instead of using the old ones, of which noone knows how
long they will be manufactured...

greetings from West Germany, Tilmann Reh

disclaimer: I have no connection to the companies mentioned above, instead of
using their chips with great effort.