National Instruments GPIB-SCSI-A, Руководство пользователя

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G Mode Functions Chapter 7
GPIB-SCSI-A User Manual 7-110 © National Instruments Corp.
wrext (continued)
The Logical Block Address notifies the Target as to where the
data is written on the device. The Transfer Length is the
number of blocks that the Target must obtain from the
GPIB-SCSI-A and write during the Data Out phase.
During the execution of this command, if the GPIB-SCSI-A
encounters a phase which it does not expect, an EPHS error
indication results. For a list of the expected phases, refer to
the section titled Handling of SCSI Phases in G Mode in
Chapter 6, Programming in G Mode.
Refer to your SCSI device documentation for expected values
in each byte of the Command Descriptor Block and the SCSI
phases that the device creates during the execution of this
command.
If you enter
wrext?
, the GPIB-SCSI-A places the last used
values for
logical block address
and
transfer
length
into the Command and Status Channel buffer
followed by a <CR><LF>.
logical block address
represents a 32-bit unsigned
number. Correct values range from 0 to 4,294,967,296.
transfer length
represents a 16-bit unsigned number.
Correct values range from 0 to 65,535. If numbers that are too
large are entered, there is a syntax error in a number, or there
are no numbers, the GPIB-SCSI-A aborts the command with
an EARG error indication.
See Also: blksze, dtin, dtout, pad, rdext, read, write, and Appendix D,
Operation of the SCSI.