[rescue] Supported CPU speeds on Ultra 2 motherboards (was: Blade 100, ...)

[Ron Wickersham]

On Thu, 8 Jun 2006, Ahmed Ewing wrote:

> Date: Thu, 8 Jun 2006 17:25:15 -0400
> From: Ahmed Ewing <aewing at townisp.com>
> To: The Rescue List <rescue at sunhelp.org>
> Subject: Re: [rescue] Supported CPU speeds on Ultra 2 motherboards (was:
>     Blade 100, ...)
>
> On Jun 8, 2006, at 1:59 PM, Arthur Wouk wrote:
>
> > re: the following: it anyone is throwing out either an ultra-2 capable
> > of having faster than 300mhz cpus (i have the older mother board and
> > can't go up) or an ultra 30 capable of faster processors, just send me
> > one. i'll pay the shipping and packing. no tower machines, though.
> >
> > put rescue in the Subject line, please, for my procmail filters.
>
> I don't know that any of the 300MHz-capable boards *can't* do 400MHz.
> IIRC, only the really old 501-2487 motherboard was limited to 200MHz
> (there's no frequency select jumper between CPU0 and the SBus
> connectors at all), and any rev of 501-3132 should be able to do 300MHz
> or 400MHz.
>
> What might not be immediately clear from the silkscreening for the
> jumpers (again, IIRC... haven't been wrist-deep in a U2 in a few years)
> is that you need to jumper the box as if it were a 200MHz CPU for the
> 400MHz to work. This is due to the required bus speed multipliers for
> the CPU.

confirming, the system boards manufactured even before the 400MHz processors
were available work with them, so your system board has to be some rev of
501-3132.  the system engineering handbook says:

J2301
1-2	In 	divide by 3 mode (250MHZ/300MHz)
2-3 	In	divide by 2 (167MHz/200MHz) divide by 4 (400MHz)

viewing the board from the rear panel, the junper far on the right side of
the board just above the SBus connectors and was oriented two ways:

J2301 is horizontal on FAB 270-2487-06 and
vertical on FAB 270-2487-08/09/10/11

the silkscreening will show you which pins to connect but you have to move
the jumper when moving from 300MHz to 400MHz.

-ron