Scsi interrupt status one (sist1), Register: 0x43 – Avago Technologies LSI53C896 User Manual
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Registers
Version 3.3
Copyright © 1998–2003 by LSI Logic Corporation. All rights reserved.
Register: 0x43
SCSI Interrupt Status One (SIST1)
Read Only
Reading the SIST1 register returns the status of the various interrupt
conditions, whether they are enabled in the
SCSI Interrupt Enable One (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
[7:5]
SBMC
SCSI Bit Mode Change
4
This bit is set when the DIFFSENS pin detects a change
in voltage level that indicates the SCSI bus has switched
between SE, LVD or HVD modes.
R
Reserved
3
STO
Selection or Reselection Time-Out
2
The SCSI device which the LSI53C896 SCSI function is
attempting to select or reselect does not respond within
the programmed time-out period. Refer to the description
of the
register, bits [3:0], for
details on the time-out timer.
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. Refer to the description of the
register, bits [3:0], for details
on the general purpose timer.
HTH
Handshake-to-Handshake Timer Expired
0
This bit is set when the handshake-to-handshake timer
expires. The time measured is the SCSI Request to
Request (target) or Acknowledge-to-Acknowledge
(initiator) period. Refer to the description of the
register, bits [7:4], for details
on the handshake-to-handshake timer.
7
5
4
3
2
1
0
R
SBMC
R
STO
GEN
HTH
0
0
0
0
0
0
0
0