2-26
C141-C011
If the TARG enters the MESSAGE IN phase and first sends the MESSAGE REJECT message to
the INIT immediately after the INIT has responded with the WIDE DATA TRANSFER
REQUEST message, such message exchange is made invalid and the two SCSI devices shall set
the 8-bit data bus width between them.
(4)
Valid period of wide data transfer mode
After the exchange of WIDE DATA TRANSFER REQUEST message, the data bus width
determined between the two SCSI devices shall be kept valid until when:
•
TARGET RESET MESSAGE reception
•
RESET condition ("hardware RESET") occurrence
•
Transfer width change between the same SCSI devices
•
Power turned off
•
Change in the transceiver mode (e.g., LVD mode to SE mode).
The default data bus width is 8 bits between SCSI devices. The data bus width shall be initialized
to 8 bits when the power supply is turned on, a TARGET RESET message is received, or when a
RESET condition occurs.
(5)
Wide mode transfer of IDD
a. Mode
setting
When the IDD recognizes the wide mode data transfer to be set, the INIT can select whether
the IDD sends the WIDE DATA TRANSFER REQUEST message to the INIT by sending the
CHANGE DEFINITION command.
For details on setting, refer to Section 3.1.4 in the SCSI Logical Specifications.
b. Data bus width status determination
(a) Default 8-bit mode status
The default 8-bit data bus width mode is selected automatically when the power supply is
turned on, a RESET condition occurs, or the TARGET RESET message is received
(initial state). Each INIT has this default bus width mode. When the WIDE DATA
TRANSFER REQUEST message is first exchanged between SCSI devices, the 8-bit or
16-bit data bus width is set between them.
(b) Data bus width determination status
This status occurs when the default data transfer mode has been released and a data bus
width has been determined. This status can be set on each INIT, and the data bus width of
each INIT may differ.
Data is transferred within the data bus width set to the INIT based on the SCSI ID of the
INIT which is identified in the SELECTION phase.
If the INIT is in this state, the IDD does not request for a change of data bus width. If its
change is requested by the INIT, the IDD shall respond to it and change the data bus width.
When changing the WIDE DATA TRANSFER REQUEST message, if the setting sequence
Содержание MAW3073 SERIES
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Страница 27: ...C141 C011 1 9 M M 0 61 5 16 0 001 0 396 Figure 1 5 SCSI interface connector cable side 16 bit SCSI ...
Страница 61: ...C141 C011 1 43 2 SE Fast 20 Figure 1 21 is the Fast 20 measurement point Figure 1 21 Fast 20 Measurement Point ...
Страница 69: ...C141 C011 1 51 Figure 1 26 ARBITRATION phase ...
Страница 116: ...1 98 C141 C011 Figure 1 43 Bus phase sequence 1 of 2 ...
Страница 117: ...C141 C011 1 99 Figure 1 43 Bus phase sequence 2 of 2 ...
Страница 118: ...1 100 C141 C011 Figure 1 44 Example of bus phase transition at execution of a single command 1 of 5 ...
Страница 119: ...C141 C011 1 101 Figure 1 44 Example of bus phase transition at execution of a single command 2 of 5 ...
Страница 120: ...1 102 C141 C011 RESELECTION Figure 1 44 Example of bus phase transition at execution of a single command 3 of 5 ...
Страница 121: ...C141 C011 1 103 Figure 1 44 Example of bus phase transition at execution of a single command 4 of 5 ...
Страница 122: ...1 104 C141 C011 Figure 1 44 Example of bus phase transition at execution of a single command 5 of 5 TASK COMPLETE ...
Страница 127: ...C141 C011 1 109 Figure 1 47 SPI information unit sequence during initial connection ...
Страница 128: ...1 110 C141 C011 Figure 1 48 SPI information unit sequence during data type transfers ...
Страница 129: ...C141 C011 1 111 Figure 1 49 SPI information unit sequence during data stream type transfers ...
Страница 130: ...1 112 C141 C011 Figure 1 50 SPI information unit sequence during status transfers ...
Страница 154: ...1 136 C141 C011 Figure 1 56 Connection to the LVD receivers ...
Страница 160: ...2 2 C141 C011 Figure 2 1 Message format ...
Страница 165: ...C141 C011 2 7 Figure 2 2 SCSI pointer configuration ...
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