
1/11/87
Rob Horning

I finished the summary of the simulations that I did for the clock and
had a meeting to discuss my assumptions and results.  I passed this on
to Rick Luebs.  He is going to work on getting better models of the
clock loading which he hopes will improve the timing significantly.

I loaded the my cross-talk test board and started looking at some of the
signals.  What I have seen so far is, to cross a bus in the signal layers
that do not have a plane between them should not be a major problem.  As
I expected, the effect of ground bounce will be doubled, because we do
not terminate our busses.  I am worried that this effect is not being taken
into account in the bus simulations that are being done.  I will look into
this.

Mark Forsyth asked me to give him feedback on some proposed pinouts for the
32kx8 SRAM.  I have written a memo giving him feedback on the proposals and
also included a proposal for a package and pinout that I think would be
ideal.  I plan to get this out today.

I looked at the outputs on the 16kx4 Hitachi SRAM's on Topgun.  Rich Luebs
wants to use a higher output level than 2 volts for PCX.  I feel that we
should be able to do this because we will not have a load resistor.  The
SRAM's on Topgun have an output high level of about 3.3 volts.  Rick is
going to assume that we can use a high level of 2.5 volts.  He will still
use a low level of .8 volts.

I spent a little time looking at the Silverfox schematics and discussed some
concerns with Don Zimmer.

