LSI 53C810A User Manual
Page 128
5-54
Operating Registers
R
Reserved
[7:3]
STO
Selection or Reselection Time-out
2
When the SCSI device which the LSI53C810A 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 (0xC4)
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,
should go to zero (assuming it started at
zero). As an example, suppose that the following three
data bytes and one check byte are received from the
SCSI bus (all signals are shown active HIGH):
7
0
SLPAR
x
x
x
x
x
x
x
x