[rescue] E3500 Backplane Bus Speed Question

Dave McGuire mcguire at neurotica.com
Tue Mar 9 22:10:46 CST 2004

On Mar 8, 2004, at 5:49 PM, Michael Thompson wrote:
> Prtdiag says that all of the boards in my E3500 are capable of running 
> with
> a 100 MHz backplane bus. The backplane bus is actually running at 84 
> MHz.
> Is this being limited by the 336 MHz CPUs?

   Yes...you need to bump up to 400MHz processors to run the bus at 
100MHz.  A 4:1 divider takes the CPU clocks and feeds the bus.

> One of the manuals says that the backplane clock speed can be set in
> firmware. Any idea how to do this?

   I've contacted to a buddy of mine on another list about it...he's a 
former Sun employee and he knows this stuff cold.  I'm waiting for his 
response on the OBP clock configuration stuff.


Dave McGuire                      "My tummy hurts now, but my soul
Cape Coral, FL                   feels a little better."     -Ed

More information about the rescue mailing list