siclmem.c

HP GPIB的VB和C语言库文件,参考范例.

/*
   siclmem.c
   This example program demonstrates the use of
   simple and block memory I/O methods in SICL.
*/

#include <sicl.h>
#include <stdlib.h>
#include <stdio.h>

#define VXI_INST "vxi,24"

void main () {
   INST           id;
   unsigned short *memPtr16;
   unsigned short id_reg;
   unsigned short devtype_reg;
   unsigned short memArray[2];
   int            err;

   /* Open a session to our instrument */
   id = iopen(VXI_INST);

   /*
   ==================================================================
   ======================== Simple memory I/O =======================
      = iwpeek()
      = direct memory dereference

     Note that on many platforms, the ipeek/ipoke operations are
     actually macros which expand to direct memory dereferencing.
     The notable exception is on Microsoft Windows platforms where
     ipeek/ipoke are implemented as functions.  This is necessary
     because under certain conditions, the compiler will attempt to
     optimize a direct dereference and cause a VXI memory access of
     the wrong size.  For example when masking the results of a 16
     bit read in a expression:
         data = iwpeek(addr) & 0xff;
     the compiler will simplify this to an 8 bit read of the contents
     of the addr pointer.  This would cause an error when attempting
     to read memory on a VXI card that did not support 8 bit access.
   ===================================================================
   */
   
   /* Map into memory space */
   memPtr16 = (unsigned short *)imap(id, I_MAP_VXIDEV, 0, 1, 0);

   /* ================== using peek ================================
   /* Read instrument id register contents */
   id_reg = iwpeek(memPtr16); 

   /*
      Read device type register contents
   */
   id_reg = iwpeek(memPtr16+1);

   /* Print results */
   printf("   iwpeek: ID Register = 0x%4X\n", id_reg);
   printf("   iwpeek: Device Type Register = 0x%4X\n", devtype_reg);

   /* Use direct memory dereferencing */
   id_reg =      *memPtr16;
   devtype_reg = *(memPtr16+1);

      /* Print results */
   printf("dereference: ID Register = 0x%4X\n", id_reg);
   printf("dereference: Device Type Register = 0x%4X\n", devtype_reg);

   /*
   ==================================================================
   ======================== block memory I/O ========================
      = iwblockcopy
      = iwpushfifo
      = iwpopfifo

   These commands offer the best performance for reading and writing
   large data blocks on the VXI backplane.  Note that for this
   example we are only moving 2 words at a time.  Normally these
   functions would be used to move much larger blocks of data.
   ==================================================================
   ==================================================================
   */
   
   /*
   ================== Demonstrate block read ========================
   Read the instrument id register and device type register into
   an array.
   */
   err = iwblockcopy(id, memPtr16, memArray, 2, 0); 

   /* Print results */
   printf(" iwblockcopy: ID Register = 0x%4X\n", memArray[0]);
   printf(" iwblockcopy: Device Type Register = 0x%4X\n", memArray[1]);

   /*
   ==================== Demonstrate popfifo =========================
   */
   
   /* Do a popfifo of the Id Register */
   err = iwpopfifo(id, memPtr16, memArray, 2, 0);
   
   /* Print results */
   printf(" iwpopfifo: 1 ID Register = 0x%4X\n", memArray[0]);
   printf(" iwpopfifo: 2 ID Register = 0x%4X\n", memArray[1]);

   /*
   ===================== Cleanup and exit ===========================
   */

   /* Unmap memory space */
   iunmap(id, (char *)memPtr16, I_MAP_VXIDEV, 0, 1);

   /* Close instrument session */
   iclose(id);
}