[rescue] Netra 1100/1400 => 1105/1405?

[James Lockwood]

On Thu, 23 Aug 2001, Greg A. Woods wrote:

> So they're logic lines just like the VID0-VID4 pins on an Intel Slot-1
> connector?

The UltraSparc CPU modules do supply digital lines for CPU voltage, but
the lines from the motherboards to powersupplies (on the U1/2/30/60/etc)
appear to be differential analog.  I'd welcome more information from
someone in the know.

> I think that's infinitely smarter than putting the VRMs right on the
> motherboard like PCs do (or as some older M-bus modules did too).

Actually it was mainly the newer Mbus modules (which had lower and more
critical core voltages) that required this.

> (of course it means you really do need a custom PS module too!  ;-)

Depends on how you implement the motherboard.  Sun has tried it several
ways.  The 5/10/AXi integrate voltage regulation with the motherboard, the
450 uses modular VRM's (like many PC's) and the 1/2/30/60 regulate the
core voltage in the p/s.  The 450 VRM's look similar enough to some PC
units to make me wonder if they're interchangable.

-James