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R
Reserved
STO
Selection or Reselection Time-out
The SCSI device which the LSI53C895A is attempting to
select or reselect does not respond within the
programmed time-out period. See the description of the
SCSI Timer Zero (STIME0)
information on the time-out timer.
GEN
General Purpose Timer Expired
The general purpose timer is expired. The time measured
is the time between enabling and disabling of the timer.
See the description of the
register, bits [3:0], for more information on the general
purpose timer.
HTH
Handshake-to-Handshake Timer Expired
The handshake-to-handshake timer is expired. The time
measured is the SCSI Request-to-Request (target) or
Acknowledge-to-Acknowledge (initiator) period. See the
description of the
bits [7:4], for more information on the handshake-
to-handshake timer.
Register: 0x42
SCSI Interrupt Status Zero (SIST0)
Read Only
7
6
M/A
CMP
0
0
Reading the SIST0 register returns the status of the various interrupt
conditions, whether they are enabled in the
(SIEN0)
register or not. Each bit set indicates occurrence of the
corresponding condition. Reading the SIST0 clears the interrupt status.
Reading this register clears any bits that are set at the time the register
is read, but does not necessarily clear the register because additional
interrupts may be pending (the LSI53C895A stacks interrupts). SCSI
interrupt conditions are individually masked through the
Enable Zero (SIEN0)
SCSI Registers
SCSI Timer Zero (STIME0)
5
4
3
SEL
RSL
SGE
0
0
0
register.
register bits [3:0] for more
SCSI Timer One (STIME1)
2
1
UDC
RST
0
0
SCSI Interrupt Enable Zero
SCSI Interrupt
3
2
1
0
register,
0
PAR
0
4-77
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