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160 Parallel SCSI Interface Product Manual, Rev. A
c. A SCSI device being removed shall maintain its power ground and logic ground prior to, during, and for
at least 1 ms after the disconnection of any device connector contact from the SCSI bus.
d. The SCSI device being removed or inserted shall employ transceivers that conform to the applicable
requirements in ANSI SPI-5 specification, T10/1525D, sections 7.2.2 and 7.3.5.3 for glitch-free powering
on and off. The SCSI device shall maintain the high-impedance state at the device connector contacts
during a power cycle until the transceivers are enabled. Power cycling includes on board TERMPWR
cycling caused by plugging, and SCSI device power cycling caused by plugging and switching.
Note. Any on-board switchable terminators as well as SCSI device transceivers may affect the impedance
state at the device connector contacts.
e. The SCSI device power may be simultaneously switched with the SCSI bus contacts if the power distri-
bution system is able to maintain adequate power stability to other SCSI devices during the transition
and the grounding requirements in items (b) and (c) above are met.
f. The SCSI bus termination shall be external to the SCSI device being inserted or removed.
g. Initiation or resumption of I/O processes for a newly inserted or removed SCSI device is vendor-specific
but shall not occur sooner than 200 milliseconds after the completion of the insertion or removal event.
h. Bypassing capacitors connecting to the TERMPWR line on the SCSI device being inserted or removed
shall not exceed 10 mF. For single-ended applications, SCSI bus terminations shall use voltage regula
-
tion.
Note. In a multimode environment, any insertion or removal that changes the bus mode causes a transceiver
mode change reset event (see Section
5.4.4).
Note. LVD SCSI devices may require more stringent system design to tolerate transients that occur during
Case 4 insertion or removal.
8.5 SPI-3 to SCSI-2 terminology mapping
This section contains a mapping of terminology used in SCSI-2 to the terminology used in this manual (see
Table
69).
Table 69: SPI-3 to SCSI-2 terminology mapping
SPI-3 equivalent term SCSI-2 term
abort task abort tag
abort task set abort
cable skew cable skew delay
clear task set clear queue
head of queue head of queue tag
ordered ordered queue tag
simple simple queue tag
target reset bus device reset
task I/O process
task complete command complete
task set queue