User`s manual

Overview
2-10 Single Board Computers SCSI Software UserÕs Manual
2
Single Step This interrupt is generated only in a special diagnostic mode
enabled by recompiling the Firmware source code. If enabled,
the SIOP generates an interrupt after the successful execution
of each SCRIPTS instruction.
Message Handling
This section deals with the messages that may be received by the Firmware
and the associated Firmware response.
CMD Complete
A SCRIPTS instruction clears the SCSI ACK signal to
complete the MSG-IN phase and then waits for the BUS FREE
phase. A command complete INT instruction interrupt is
then generated.
Save Data Pointers
A SCRIPTS instruction clears the SCSI ACK signal to
complete the MSG-IN phase and then waits for an expected
disconnect message. If a MSG-IN phase does not follow
current message phase then a protocol violation INT
instruction interrupt is generated.
Restore Data Pointers
A SCRIPTS instruction clears the SCSI ACK signal to
complete the MSG-IN phase and then the SCRIPTS transition
to the next phase dictated by the target.
Disconnect A SCRIPTS instruction clears the SCSI ACK signal to
complete the MSG-IN phase and then waits for the BUS FREE
phase. A disconnect INT instruction interrupt is then
generated.
Message Reject
A message reject INT instruction interrupt is generated. This
holds the bus in the MSG-IN phase while the Firmware
determines which message was rejected by the target. When
the MPU code resolves the rejected message issue, it restarts
the SCRIPTS at an instruction which clears the SCSI ACK
signal to complete the MSG-IN phase.