Measurement-computing GPIB-488 Manual do Utilizador descarregar pdf (Página 46)

Chapter 3 GPIB 488.1 Library Reference

GPIB-488 3-33 Programming Reference Manual

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.

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, IBSTA.

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.

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

1 2 ... 41 42 43 44 45 46 47 48 49 50 51 ... 115 116

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Measurement-computing GPIB-488 Manual do Utilizador Página 46