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Chapter 7
ibconf—Interface Bus Configuration Utility
Enable Auto Serial Polling (Board Characteristic Only)
This option enables or disables automatic serial polls of devices when the GPIB
Service Request (SRQ) line is asserted. Positive poll responses are stored
following the polls and can be read with the ibrsp device function. Normally,
this feature does not conflict with devices that conform to the IEEE 488 standard.
If there is a conflict with a device, a no response for this field disables this
feature. The default option for this characteristic is yes.
Enable CIC Protocol (Board Characteristic Only)
If a device-level NI-488 call is made after control has been passed to another
device, enabling this protocol causes the board to assert SRQ with a Serial Poll
status byte of hex 42. The current Controller must recognize that the board
wants to regain control. If the current Controller passes control back to the
board, the device call proceeds as intended. If control is not passed within the
timeout period, the ECIC error is returned. If the CIC protocol is disabled, ECIC
is returned immediately if a device call is made after control has been passed.
The default option for this characteristic is no.
Bus Timing (Board Characteristic Only)
This field specifies the T1 delay of the source handshake capability for the board.
This delay determines the minimum amount of time, after the data is placed on
the bus, that the board may assert DAV during a write or command operation. If
the total length of the GPIB cable length in the system is less than 15 m, the
value of 350 ns is appropriate. Other factors might affect the choice of the T1
delay, although they are unlikely to affect your system setup. Refer to the IEEE
488.1 standard, Section 5.2, for more information about these other factors. The
default for this option is 500 ns.
Parallel Poll Duration (Board Characteristic Only)
This field specifies the length of time the driver waits when conducting a parallel
poll. For a normal bus configuration (the Controller and devices on the same
bus), use the default duration of 2 µs. If you are using a GPIB bus extender in
transparent parallel poll mode, you should increase the poll duration to 10 µs so
that the bus extender can operate transparently to your applications.
© National Instruments Corp.
7-13
NI-488.2M SRM for OS/2
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