21020285 D User’s Guide
Chapter 8 Details of Usage
Page 8 - 14 Target Mode Usage and SCSI Protocol Handling
Parity error conditions
If a parity error is detected on incoming message bytes, the adapter will receive
all of the remaining message bytes (until ATN is negated) and then request the
message bytes again. During the retry, the state of the ATN line will not be
monitored; it is required that the initiator respond correctly to this retry
sequence.
If a parity error is detected on incoming command or data bytes, the adapter
will stop the transfer and send a Restore Pointers message to the initiator. The
transfer will then be restarted. Target Mode Response commands m ust include
a Save Data Pointer message before disconnecting to ensure that this retry
technique will work.
Message parity errors
If a Message Parity Error message is received from the initiator in response to
a message sent to it, the adapter will return to the Message In phase and resend
the entire message.
If a Message Parity Error message is received at any other time, the adapter
will go to the Bus Free phase and report this illegal message to the host.
Initiator-detected Error messages
If an Initiator-detected Error message is received from the initiator right after
a data transfer, the transfer will be halted and the Restore Pointers message will
be sent to the initiator. The transfer will then be restarted. It is required that the
host always send a Save Data Pointer message before disconnecting to ensure
that this retry technique will work.
If an Initiator-detected Error message is received from the initiator right after
the Status phase, the Restore Pointers message will be sent to the initiator. The
status byte will then be resent.
If an Initiator-detected Error message is received from the initiator right after
any other phase, the message will be treated as an unexpected message and will
be sent to the host for action.
TargetRoutines
The adapter does not support target routines. The adapter will not detect the
receipt of an Identify message for a target routine. The host should send a Check
Condition status if the initiator attempts to select a target routine.