Chapter 5
S Mode Functions
© National Instruments Corp.
5-15
GPIB-SCSI-A User Manual
cac - Become Active Controller
Type:
Specialized Controller function
Purpose:
Use
cac
to change the GPIB-SCSI-A from Standby
Controller to Active Controller when the I/O and bus
management functions do not meet your needs.
cac
gives
you more precise control over the GPIB than the I/O and bus
management functions.
Format:
Bit
7
6
5
4
3
2
1
0
Byte
0
Opcode = C0H
1
Reserved
2
Reserved
3
Reserved
Mode
4
Reserved
5
Reserved
Remarks:
If Mode is 0, the GPIB-SCSI-A takes control immediately–
that is, it takes control asynchronously. If Mode is 1, the
GPIB-SCSI-A takes control after any handshake in progress
completes–that is, it takes control synchronously.
If you call
cac
and the GPIB-SCSI-A is not Controller-In-
Charge (CIC), the GPIB-SCSI-A records the ECIC error,
issues a CHECK CONDITION status response, and sets the
Sense Key to ERROR.
The power-on default Controller status of the GPIB-SCSI-A is
Idle Controller.
The information transfer phases that the GPIB-SCSI-A drives
the SCSI through after selection are the Command, Status, and
Message In phases.
See Also:
gts and sic.
Содержание GPIB-SCSI-A
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Страница 355: ...Appendix C Operation of the GPIB National Instruments Corp C 7 GPIB SCSI A User Manual Figure C 2 Linear Configuration ...
Страница 356: ...Operation of the GPIB Appendix C GPIB SCSI A User Manual C 8 National Instruments Corp Figure C 3 Star Configuration ...