National Instruments GPIB-PC User Manual
Page 65
GPIB-PC Functions — Overview
Section Four
GPIB-PC User Manual
4-4
©National Instruments Corp.
RQS (d)
RQS appears only in the status word of a device function
call. Indicates that the device is requesting service. It is
set in the status word whenever the hex 40 bit is asserted in
the device's serial poll status byte. The serial poll which
obtains the status byte may be the result of an
IBRSP
call,
or it may be done automatically by the handler. It is
cleared when the user has called
IBRSP
to read 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 (db) CMPL specifies the condition of outstanding I/O operations.
It is set in the status word whenever I/O is not in progress;
that is, whenever I/O is complete. It is cleared while I/O is
in progress.
LOK (b)
LOK specifies whether the board is in a lockout state.
While LOK is set, the function
IBLOC
is effectively
inoperative for that board. It is set whenever the GPIB-PC
detects the Local Lockout (LLO) message has been sent
either by the GPIB-PC or by another Controller. It is
cleared when the Remote Enable (REN) GPIB line
becomes unasserted either by the GPIB-PC or by another
Controller.
REM (b)
REM specifies whether the board is in remote state. It is
set whenever the Remote Enable (REN) GPIB line is
asserted and the GPIB-PC detects its listen address has
been sent either by the GPIB-PC or by another Controller.
It is cleared whenever REN becomes unasserted, or when
the GPIB-PC as a Listener detects the Go to Local (GTL)
command has been sent either by the GPIB-PC or by
another Controller, or when the
IBLOC
function is called
while the LOK bit is cleared in the status word.
CIC (b)
CIC specifies whether the GPIB-PC is the Controller-In-
Charge. It is set whenever the
IBSIC
function is called
while the GPIB-PC is System Controller, or when another
Controller passes control to the GPIB-PC. It is cleared
whenever the GPIB-PC detects Interface Clear (IFC) from
the System Controller, or when the GPIB-PC passes control
to another device.
ATN (b)
ATN specifies the state of the GPIB Attention (ATN) line.
It is set whenever the GPIB ATN line is asserted and
cleared when the ATN line is unasserted.
TACS (b)
TACS specifies whether the GPIB-PC has been addressed