Register: 0x44 – LSI 53C875A User Manual
Page 171
SCSI Registers
4-79
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
register, bits [3:0], for more
information 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. See the description of the
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. The time measured is the SCSI Request to
Request (target) or Acknowledge-to-Acknowledge
(initiator) period. See the description of the
register, bits [7:4], for more 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
check on 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
x
x
x
x
x
x
x
x