National Instruments GPIB-SCSI-A, Руководство пользователя

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G Mode Functions Chapter 7
GPIB-SCSI-A User Manual 7-16 © National Instruments Corp.
dtin - Transfer Data In Information from Selected
SCSI Target
Type: SCSI Function
Syntax:
dtin
<CR>
Purpose: Use
dtin
if the Target is in the Data In phase and you want
to receive data from the selected Target. This is a low-level
command that you must use if the high-level commands
provided by the GPIB-SCSI-A do not work properly with your
device.
Remarks: Use the
dtin
command in your low-level command sequence
to perform the Data In phase for the SCSI bus.
Because this command is used to transfer SCSI data (which is
usually grouped in blocks) to the GPIB (which does not group
data in blocks), the GPIB-SCSI-A uses the GPIB END
condition to prevent locking up the system. When the
GPIB-SCSI-A detects that it is about to send the last data byte
from the SCSI, the GPIB-SCSI-A asserts the EOI* signal to
indicate that the next byte will be the last GPIB byte. This
stops your device from receiving data and completes the cycle.
If the Target enters the Status phase before entering the Data
In phase,
dtin
aborts the operation with an error indication of
EPHS.
If there is anything following
dtin
, the command aborts the
operation with an EARG indication.
See Also: read, rdext, and Appendix D, Operation of the SCSI.