Scsi Messages And Status Codes; Scsi Messages; Inbound Messages - Seagate Viper 200 Scsi Interface Manual

Page 10

SCSI Messages and Status Codes

SCSI Messages

Inbound messages

The SCSI message codes, descriptions, and directions are given in the following
table. Each of these SCSI messages are supported by the Seagate LTO drive.
Code Description
00h Command Complete
01h Extended Message*
02h Save Data Pointers
03h Restore Pointers
04h Disconnect
05h Initiator Detected Error
06h Abort
07h Message Reject
08h No Operation
09h Message Parity Error
0Ch Bus Device Reset
23h Ignore Wide Residue
80h+ Identify
In = Drive to host
Out = Host to drive
* Only two extended messages are Supported: Synchronous Data Transfer Request and Wide Data
Transfer Request.
The following table lists drive to host SCSI messages and their definitions.
Message Hex Code
Command 00h
Complete
Disconnect 04h
Extended 01h
Message
Identify 80h+
Ignore Wide 23h
Residue
Definition
This message is sent by the drive at the end of the status phase to
indicate that a command is complete. Once the message is sent, the
drive releases the bus and goes to Bus Free
This message is sent by the drive to indicate that it is about to dis-
connect from the bus and go to Bus Free. During a Data phase, it is
always preceded by a Save Data Pointers message. If a Message
Reject message is received in response to this message, then the
disconnect is prevented.
See page 11 for a description of extended message support
An Identify in message is sent to the initiator during reconnect to in-
dicate which Logical Unit is reconnecting. The Disconnect Privilege
and LUNTAR flags will both be clear
This message is sent by the drive to the initiator to indicate that a
byte on a wide bus is not valid. This will be supported whenever a
wide transfer is active.
LTO SCSI Interface Manual
Direction
In
In/Out
In
In
In
Out
Out
In/Out
Out
Out
Out
In
In/Out