Re: Seeking Intel i960RP opinions/experiences

[Alan Deikman <alan@znyx.com>]

>We're currently considering an upgrade to a multi-PowerPC board we make to
provide twin PCI busses for improved allocation of I/O bandwidth. We could
just slap a DEC PCI-to-PCI bridge chip on it, but the i960RP looks like an
apparently sensible alternative to what would otherwise be an i960 + PCI9060
+ DEC bridge.

The i960RP has more than that on it -- it includes the DRAM controler plus
the I20 FIFO stuff.  You also get an I2C controller.  It's sort of like
Intel's PCI CPU toybox.

The biggest performance advantage of the i960RP architecture is that its
960 memory is a direct target to masters on both the primary and
secondary bus.  With the PPB+9060 architecture masters on the primary
PCI bus have to go through two bridges to get to the memory.

I have had OEM customers say that they don't think much of the i960RP as
a PCI-PCI bridging -- certainly the specs are lower than that of, say,
the DEC 21152.  How it would make a difference in a specific application
would have to be carefully thought out or, better yet, tested.

>However, I noticed some banter a while ago on the reflector about heat and
power consumption issues. Should we be concerned about these? 

We haven't seen heat problems with the RP.  If you design your system
board properly and pay attention to the specs of the parts, I don't see
why you should have a problem.

>And a specific question: can you disable the secondary bus arbiter (so you
can do the arbitration yourself)?

Why would you want to?

Regards,

--------------------------------
  Alan Deikman, ZNYX Corporation
  alan@znyx.com
“üê