Measurement-computing GPIB-488 Uživatelský manuál stáhnout pdf (Strana 45)

Chapter 3 GPIB 488.1 Library Reference

Programming Reference Manual 3-32 GPIB-488

IBPPC

Enables/Disables parallel polling of the specified device.

Syntax

C ibppc (int boarddev, int command)

Parameters

boarddev is an integer containing the board or device handle. This value is obtained by

calling the

ibfind routine.

command is a valid parallel poll enable/disable message or 0. If command represents a PPE

message, then the device will use that message to respond to a parallel poll. Valid PPE

messages range from 60 to 6F hex. The PPE specifies the GPIB data line (DIO1 through

DIO8) on which the device is to respond and whether that line is to be asserted or unasserted.

The PPE byte is of the format:

Where

SENSE indicates the condition under which the data line is to be asserted. The device

compares the value of the sense bit to its IST (individual status) bit and responds

appropriately. For example, if SENSE = 1, the device will drive the line TRUE if its IST = 1

or FALSE if IST = 0.

P2–P0 specify which GPIB data line should be used to respond to a parallel poll, as shown in

Table 3-5.

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 1 1 DIO8

1 1 0 DIO7

1 0 1 DIO6

1 0 0 DIO5

0 1 1 DIO4

1 2 ... 40 41 42 43 44 45 46 47 48 49 50 ... 115 116

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Measurement-computing GPIB-488 Uživatelský manuál Strana 45