Changes for SPI X3T10/94-038 Rev 3
Paul D. Aloisi 603-429-8687
aloisi at uicc.com
Sun May 22 14:20:01 PDT 1994
This is the out come of the X3T10/94-038 Rev 2 presentation in the
18 May, 1994 SCSI working group meeting, and follow up individual
Slide one corrects some of the hot plugging issues that have arisen
in the implementations.
Slide two addresses slewing problems that would occur if Voh is
left unrestricted. Slewing from 5.25 Volts would either create too
fast of a fall time or too long of a slew time. The first section
addresses the driver, the second section addresses a parameter
that was left out of the Terminator specification.
(Text Version of the Slides)
X3T10/94-038 Rev 3
Proposed Changes to SPI
Annex A.3 and A.4 Change
d) The SCSI device being removed or inserted shall employ
transceivers that conform to the requirements for glitch-free
power on/off in 7.1.2 and 7.2.2. The SCSI device shall maintain the
high-impedance state at the device connector contacts during a power
cycle until the transceiver is enabled. Power cycling includes on
board termpwr cycling, caused by plugging, and device power cycling
caused by plugging or switching. Note that any on board switchable
terminator as well as the device transceivers may affect the
impedance state at the device connector contacts.
Annex A.4 Addition Limit Termpwr Bypassing
g) Bypassing capacitors connecting to the termpwr line on the device
being inserted or removed shall not exceed 10 uF. For single-ended
applications, bus termination shall use voltage regulation on both
ends (Reference SCSI-2 Alternative 2).
7.1.2 Voh allows 5.25V Maximum, Add Note 8
Note 8 With these specifications voltages greater than 3.24 can
not be directly driven by the driver, but voltages above 3.24
may occur as reflections.
7.1.1 Single-ended Termination, Add f
f) The terminator shall not source current above 3.24 V d.c.
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