
SCSI Registers
4-49
SIGP bit causes this instruction to jump to the alternate
address immediately. The instructions at the alternate
jump address should check the status of SIGP to
determine the cause of the jump. The SIGP bit is usable
at any time and is not restricted to the wait for
selection/reselection condition.
SEM
Semaphore
The SCRIPTS processor may set this bit using a
SCRIPTS register write instruction. An external processor
may also set it while the SYM53C1010 SCSI function is
executing a SCRIPTS operation. This bit enables the
SCSI function to notify an external processor of a
predefined condition while SCRIPTS are running. The
external processor may also notify the SYM53C1010
SCSI function of a predefined condition and the
SCRIPTS processor may take action while SCRIPTS are
executing.
4
CON
Connected
This bit is automatically set any time the SYM53C1010
SCSI function is connected to the SCSI bus as an initiator
or as a target. It is set after successfully completing
selection or when the SYM53C1010 SCSI function
responds to a bus-initiated selection or reselection. It is
also set after the SCSI function wins arbitration when
operating in the low level mode. When this bit is cleared,
the SYM53C1010 SCSI function is not connected to the
SCSI bus.
3
INTF
Interrupt-on-the-Fly
This bit is asserted by an INTFLY instruction during
SCRIPTS execution. SCRIPTS programs do not halt
when the interrupt occurs. This bit can be used to notify
a service routine, running on the main processor while
the SCRIPTS processor is still executing a SCRIPTS
program. If this bit is set, when the
Interrupt Status Zero
(ISTAT0)
register is read it is not automatically cleared. To
clear this bit, write a one to it. The reset operation is
self-clearing.
2
Note:
If the INTF bit is set but SIP or DIP is not set, do not
attempt to read the other chip status registers. An interrupt-