No subject

Mon Apr 25 07:28:36 PDT 1994

PROPOSED CHANGE TO SPI (X3T9.2/93-149 Rev 3)
I believe that this proposal is intended to limit the load
instantaneously placed on Termpower by a device being "hot plugged."
I do not think it is intended to place a limit on the capacitance put
on Termpower by a terminator itself, however, unless that terminator
is inside a non-terminating device with its internal terminator

As correctly pointed out in the proposal, a device with a big
capacitor will draw a large amount of charge current as it is "hot
plugged,"  and this charging current may cause a glitch in Termpower.
Therefore a device's capacitive load on Termpower needs to be limited
as proposed. Terminators, however, when enabled and acting as
terminators, are *never* unplugged in a high availability
configuration and therefore their capacitive load on Termpower should
not cause a problem.

I think that the wording of the proposal should be clarified to ensure
that the capacitive limits do not apply to terminators which are
enabled and acting as terminators.

                                        Giles Frazier
                                        IBM Austin
                                        gfrazier at
                                        (512) 838-1802

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