CHAPTER 2
SCSI MESSAGE
2.1 Message
System
2.2 SCSI
Pointer
2.3 Message
Explanation
This chapter describes SCSI messages and their operations for controlling the operation sequence of the
SCSI bus.
Note:
The HDD operates as a target device (TARG) on the SCSI bus. The HDD is referred to as the
TARG in this chapter except when its clear identification is required.
2.1 Message
System
The message system provides procedures for information (or message) transfer between two SCSI
devices on the SCSI bus in order to control a series of bus phase sequence during command
execution. The messages are transferred over the SCSI data bus in the MESSAGE OUT and
MESSAGE IN phases.
2.1.1 Message
format
There are three message formats are listed below. The first byte of the message is a message code
in any format. (See Figure 2.1.)
•
One-byte message: This consists of a message code only.
•
Two-byte message: Message code is between X'20' and X'2F'. This consists of a message
code and one-byte length parameter.
•
Extended message: This is a message of multiple bytes length message code of X'01'.
The Extended message code and message length are specified in the
message.
C141-C015
153
Summary of Contents for MBA3300 NP SERIES
Page 6: ...This page is intentionally left blank ...
Page 18: ...This page is intentionally left blank ...
Page 69: ...C141 C015 63 Figure 1 26 ARBITRATION phase ...
Page 81: ......
Page 117: ...1 37 C141 C007 Figure 1 43 Bus phase sequence 1 of 2 ...
Page 118: ...38 C141 C015 Figure 1 43 Bus phase sequence 2 of 2 ...
Page 128: ...48 C141 C015 Figure 1 47 SPI information unit sequence during initial connection ...
Page 129: ...1 49 C141 C007 Figure 1 48 SPI information unit sequence during data type transfers ...
Page 130: ...50 C141 C015 Figure 1 49 SPI information unit sequence during data stream type transfers ...
Page 131: ...1 51 C141 C007 Figure 1 50 SPI information unit sequence during status transfers ...
Page 155: ...1 75 C141 C007 Figure 1 56 Connection to the LVD receivers ...
Page 161: ...Figure 2 1 Message format 154 C141 C015 ...
Page 166: ...Figure 2 2 SCSI pointer configuration C141 C015 159 ...
Page 201: ...This page is intentionally left blank ...
Page 205: ...This page is intentionally left blank ...
Page 207: ...This page is intentionally left blank ...
Page 208: ......
Page 209: ......