Measurement Computing GPIB-488 User Manual
Page 105
Appendix B
IBSTA
GPIB-488
B-3
RQS
Device Requesting Service. If this bit = 1, a device is requesting service. RQS
is set in the status word whenever the hex 40 bit is asserted in the serial poll
status byte of the device. The serial poll that obtained the status byte may have
been the result of an
ibrsp
or the poll may have been automatically performed
if automatic serial polling is enabled. RQS is cleared when an
ibrsp
reads the
serial poll status byte that caused the RQS. An
ibwait
on RQS should only be
done on devices that respond to serial polls.
CMPL
I/O Completed. When set, this bit indicates that all I/O operations have been
completed. CMPL is cleared while I/O is in progress.
LOK
Lockout State. Indicates whether the board is in a lockout state. While LOK is
set, the
EnableLocal
routine or
ibloc
function is inoperative for that board.
LOK is set whenever the GPIB board detects the Local Lockout (LLO) message
has been sent either by the GPIB board or another Controller. LOK is cleared
when the Remote Enable (REN) GPIB line becomes unasserted by the system
controller.
REM
Remote State. If this bit = 1, the GPIB Interface Board is in the remote state
(i.e, the REN line has been asserted and the Board has been addressed as a
listener.). This bit is cleared when one of the following occurs:
•
REN is unasserted.
•
The GPIB Interface Board has been addressed as a
Listener and receives a GTL (Go to Local)
command.
•
IBLOC
is called while the LOK bit = 0.
CIC
Controller-In-Charge. If this bit = 1, it indicates that the GPIB Interface Board
is the Active Controller. This bit is set upon the following conditions:
•
If the board is the system controller and
ibsic
or
SendIFC
is executed.
•
Control is passed to the GPIB Interface Board.
•
This bit is cleared whenever the GPIB board
detects Interface Clear (IFC) from the system
controller, or when the GPIB board passes control
to another device.
ATN
Attention. If this bit = 1, ATN is asserted. Likewise, if this bit = 0, the ATN line
is unasserted.
Table B-1. Bit Definitions (Continued)
Bit
Description