Table 2.2
Extended message
Code
(hex.)
Message
Number
of bytes
Transfer
direction
ATN
release
01
SYNCHRONOUS DATA TRANSFER
REQUEST
5
TARG
↔
INIT
*
03
WIDE DATA TRANSFER REQUEST
4
TARG
↔
INIT
*
04
PARALLEL PROTOCOL REQUEST
8
TARG
↔
INIT
*
2.1.3 Message
protocol
(1)
Message implement requirements
All SCSI devices shall implement at least the TASK COMPLETE message. If a logical unit
number (LUN) for input and output operations is specified in the command (CDB), the minimum
I/O operations required on the SCSI bus can be executed without using any message other than the
TASK COMPLETE message.
Also, the SCSI device should implement the MESSAGE REJECT message against inappropriate
message reception. The SCSI device must always implement the MESSAGE REJECT message if
it supports any message other than the TASK COMPLETE message. In addition, the SCSI device
supporting the parity check of SCSI data bus should implement the MESSAGE PARITY ERROR
message.
(2) ATTENTION
condition
If SCSI device supports messages other than TASK COMPLETE message, the SCSI device
creates ATTENTION condition or responds to the ATTENTION condition.
To indicate that the TARG can support messages other than TASK COMPLETE message, the
TARG initiates MESSAGE OUT phase in response to ATTENTION condition.
Note:
If the INIT is in the ARBITRATION phase and if it generates an ATTENTION condition, it
shall assert the ATN signal before the SELECTION phase starts. If the INIT is not in the
ARBITRATION phase, it shall asserts the ATN signal when sending an SEL signal.
The TARG starts the MESSAGE OUT phase in response to the ATTENTION condition
immediately after the end of SELECTION phase. It shows that the TARG supports messages
other than the TASK COMPLETE message.
If the TARG starts the INFORMATION TRANSFER phase (other than the MESSAGE OUT
phase) when the INIT has generated an ATTENTION condition in the SELECTION phase, the
INIT should negate the ATN before responding to the first ACK signal. If the ATTENTION
condition is not generated during SELECTION phase, the TARG shall not send any message
except for the TASK COMPLETE message to the INIT.
156
C141-C015
Содержание MBA3300 NP SERIES
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Страница 27: ...C141 C015 21 M M 0 61 5 16 0 001 0 396 Figure 1 5 SCSI interface connector cable side 16 bit SCSI ...
Страница 61: ...C141 C015 55 2 SE Fast 20 Figure 1 21 is the Fast 20 measurement point Figure 1 21 Fast 20 Measurement Point ...
Страница 69: ...C141 C015 63 Figure 1 26 ARBITRATION phase ...
Страница 81: ......
Страница 117: ...1 37 C141 C007 Figure 1 43 Bus phase sequence 1 of 2 ...
Страница 118: ...38 C141 C015 Figure 1 43 Bus phase sequence 2 of 2 ...
Страница 119: ...1 39 C141 C007 Figure 1 44 Example of bus phase transition at execution of a single command 1 of 5 ...
Страница 120: ...40 C141 C015 Figure 1 44 Example of bus phase transition at execution of a single command 2 of 5 ...
Страница 121: ...1 41 C141 C007 RESELECTION Figure 1 44 Example of bus phase transition at execution of a single command 3 of 5 ...
Страница 122: ...42 C141 C015 Figure 1 44 Example of bus phase transition at execution of a single command 4 of 5 ...
Страница 123: ...1 43 C141 C007 Figure 1 44 Example of bus phase transition at execution of a single command 5 of 5 TASK COMPLETE ...
Страница 128: ...48 C141 C015 Figure 1 47 SPI information unit sequence during initial connection ...
Страница 129: ...1 49 C141 C007 Figure 1 48 SPI information unit sequence during data type transfers ...
Страница 130: ...50 C141 C015 Figure 1 49 SPI information unit sequence during data stream type transfers ...
Страница 131: ...1 51 C141 C007 Figure 1 50 SPI information unit sequence during status transfers ...
Страница 155: ...1 75 C141 C007 Figure 1 56 Connection to the LVD receivers ...
Страница 161: ...Figure 2 1 Message format 154 C141 C015 ...
Страница 166: ...Figure 2 2 SCSI pointer configuration C141 C015 159 ...
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