Thread (1 message) 1 message, 1 author, 2003-06-19

Re: RTC for MPC8xx with Linux ?

From: Wolfgang Denk <hidden>
Date: 2003-06-19 16:29:15

Dear David,

in message [ref] you wrote:
Thanks for all the answers I got over experience with the MPC852T.
One other thing I was investigating is the RTC.
What RTC solutionts are known for easy interfacing with MPC8xx processors,
that work under linux ? What's the standard ?
There is no standard. The choice  is  made  by  product  requirements
(price, accuracy, battery lifetime, etc). Then the driver is dapted -
which usually is pretty trivial.
There are a number of PC-compatible RTC chips out there, but I don't seem to
like them much, because they're generally quite expensive, have a lot of
functionality which might be nice, but is not really needed in my case.
Any experience with smaller 1-bit (or SPI) RTC's under linux ? I'm looking
basically for a Battery-backuped time-keeping counter.
See the existing driver; for example, in our kernel  trees  you  will
find support for the PCF8563, M41T11, DS12887 and similar RTCs.o

This is not a big deal. Be careful though when running  NTP  on  your
system,  especially  when  using a RTC with I2C or SPI interface. You
will have to disable the  11  minute  mode  (see  "man  hwclock"  for
details).


Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
"It is better to have tried and failed than to have  failed  to  try,
but the result's the same."                           - Mike Dennison

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
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