Avago Technologies LSI53C876E - Manual (Page 173)

SCSI Registers 4-79
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 [7:3]
STO Selection or Reselection Time-out 2
The SCSI device which the LSI53C876 SCSI function 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 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
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. The time measured is the SCSI Request to
Request (target) or Acknowledge-to-Acknowledge
(initiator) period. See the description of the
SCSI Timer
Zero (STIME0) register, bits [7:4], for more information on
the handshake-to-handshake timer.
7 3 2 1 0
R STO GEN HTH
x x x x x 0 0 0