Agilent Technologies FS2010 Guide de l'utilisateur télécharger pdf (Page 118)

118 Agilent VISA User’s Guide

4 Programming via GPIB and VXI

/* Map into memory space */

viMapAddress (vi, VI_A16_SPACE, 0x00, 0x10,

VI_FALSE,VI_NULL, &address);

================================================

Using viPeek

================================================

Read instrument id register contents */

viPeek16 (vi, address, &id_reg);

/* Read device type register contents

ViAddr is defined as a (void *) so we must

cast it to something else in order to do

pointer arithmetic. */

viPeek16 (vi, (ViAddr)((ViUInt16 *)address +

0x01),&devtype_reg);

/* Print results */

printf (" viPeek16: ID Register = 0x%4X\n",

id_reg);

printf (" viPeek16: Device Type Register =

0x%4X\n",devtype_reg);

/* Use direct memory dereferencing if

supported */

viGetAttribute( vi, VI_ATTR_WIN_ACCESS,

&accessMode );

if ( accessMode == VI_DEREF_ADDR ) {

/* assign pointer to variable of correct

type */

memPtr16 = (unsigned short *)address;

/* do the actual memory reads */

id_reg = *memPtr16;

devtype_reg = *(memPtr16+1);

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Agilent Technologies FS2010 Guide de l'utilisateur Page 118