SCSI Registers 4-79
(SIEN1) register or not. Each bit that is set indicates an occurrence of
the corresponding condition.
Reading the SIST1 clears the interrupt condition.
R Reserved [7:3]
STO Selection or Reselection Time-out 2
The SCSI device which the LSI53C875A is attempting to
select or reselect does not respond within the
programmed time-out period. See the description of the
SCSI Timer Zero (STIME0) register, bits [3:0], for more
informationonthetime-outtimer.
GEN General Purpose Timer Expired 1
This bit is set when the general purpose timer expires.
The time measured is the time between enabling and
disabling of the timer. See the description of the SCSI
Timer One (STIME1) register, bits [3:0], for more
information on the general purpose timer.
HTH Handshake-to-Handshake Timer Expired 0
This bit is set when the handshake-to-handshake timer
expires. Thetime measured is the SCSI Request to
Request (target) or Acknowledge-to-Acknowledge
(initiator) period. See the description of the SCSI Timer
Zero (STIME0)r egister,bits [7:4], formor e information on
the handshake-to-handshake timer.
Register: 0x44
SCSI Longitudinal Parity (SLPAR)
Read/Write
SLPAR SCSI Longitudinal Parity [7:0]
This register performs a bytewise longitudinal parity
checkon all SCSI data received or sent through the SCSI
core.If one of the bytes received or sent (usually the last)
is the set of correct even parity bits, SLPAR should go to
zero (assuming it started at zero). As an example,
suppose that the following three data bytes and one
7 0
SLPAR
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