Measurement Computing GPIB-488 User Manual
Page 46
Chapter 3
GPIB 488.1 Library Reference
GPIB-488
3-33
For example, if the PPE byte 01101011 (hex 6B) is sent, the device will drive DIO4 true if its
IST bit = 1, or false if its IST bit = 0.
If
command
is 0 or represents a PPD (Parallel Poll Disable) message, the current PPE
(Parallel Poll Enable) configuration is cancelled. Valid PPD messages range from 70 to 7F
hex. The PPD is of a similar format to the PPE byte, for example:
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
iberr
will contain an error code, if an error occurred. Contains the previous value of
command
if no error occurs.
Usage Notes
If
boarddev
specifies a GPIB interface board, this routine sets the board's Local Poll Enable
(LPE) message to
command
.
If
boarddev
specifies a device, the GPIB Interface Board associated with the device
addresses itself as a Talker, unlistens all devices (sends a UNL), addresses the specified device
as a Listener, and sends the PPC command followed by a PPE or PPD command.
Example
This example configures a device at PAD 2 to send DIO7 true if its IST bit = 1.
C
int dev2;
dev2 = ibdev (0,2,0,13,1,0);
ibppc (dev2, 0x6B);
0
1
0
DIO3
0
0
1
DIO2
0
0
0
DIO1
7
6
5
4
3
2
1
0
0
1
1
0
SENSE
P2
P1
P0
Table 3-5. Values for P2–P0
P2
P1
P0
GPIB Data Line