
5-48
Registers
external processor may also notify the SYM53C895 of a
predened condition, and the SCRIPTS processor may
take action while SCRIPTS are executing.
CON
Connected
3
This bit is automatically set any time the SYM53C895 is
connected to the SCSI bus as an initiator or as a target.
It is set after successfully completing selection or when
the SYM53C895 has responded to a bus-initiated
selection or reselection. It is also set after the
SYM53C895 wins arbitration when operating in low-level
mode. When this bit is clear, the SYM53C895 is not
connected to the SCSI bus.
INTF
Interrupt on the Fly
2
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
(ISTAT) register is read it does not automatically clear. To
clear this bit, it must be written to a one. The reset
operation is self-clearing.
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-on-the-y interrupt must be cleared before
servicing any other interrupts indicated by SIP or DIP.
This bit must be written to one in order to clear it after it
has been set.
SIP
SCSI Interrupt Pending
1
This status bit is set when an interrupt condition is
detected in the SCSI portion of the SYM53C895. A SCSI
interrupt can occur under these conditions:
A phase mismatch (initiator mode) or SATN/ becomes
active (target mode)
An arbitration sequence completes
A selection or reselection timeout occurs
The SYM53C895 was selected
The SYM53C895 was reselected