Subject: Re: RTC on AlphaStation 600
To: Matt Thomas <>
From: Sean Davis <>
List: port-alpha
Date: 09/03/2003 06:20:57
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On Wed, Sep 03, 2003 at 02:28:02AM -0700, Matt Thomas wrote:
> On Wednesday, September 3, 2003, at 02:20 AM, Sean Davis wrote:
> >Okay, this is a two-part question:
> >I have an AlphaStation 600 5/266, which has a DS1287 RTC (mcclock(4))=20
> >on the
> >motherboard. Maxim/Dallas Semiconductor is sending me a DS12887 (which=
> >is
> >their replacement for the 'outdated' DS1287, supposedly=20
> >pin-compatible) for
> >free. My questions are:
> >
> >1) will mcclock(4) know WTF is going on if I replace the DS1287 RTC=20
> >with a
> >   DS12887 RTC (the hardware info implies as much, but docs and=20
> >experience
> >   are different ;)
> Actually, the real question is will the SRM be happy with it.  If it's
> software compatible, it'll probably wonder where all the settings went.
> So be prepared to reenter boot_device, etc.

Yes, that is true. However I'm ready to reenter settings if necessary. I'm
just wondering if it's possible. The docs I can find on the DS12887 imply
that most things made for the DS1287 should work with the DS12887. There is
no list of specific things using the DS1287, but it's safe to assume an
AlphaStation 600 uses one, given the first few lines of the mcclock manpage
and the fact that mcclock is detected and attached on this machine.

Also, aren't the SRM settings stored on the same flash as the SRM/AlphaBIOS
stuff itself? ISTR reading that there was something like 1k allocated for
settings in the flash... of course I can't find that pdf now...

> >2) Is it worth the effort of removing the motherboard, desoldering the
> >   DS1287, and soldering in the DS12887 to try it? has anyone done this
> >   before?
> Is the DS1287 actually soldered?  Usually Digital used sockets for clock
> chips.

I'm not sure; I have not examined the motherboard that closely. If it is in
a socket, not soldered in, that makes replacing it with the old one if it
doesn't work a whole lot easier.


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