Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 171)

9E. C Languages II. SOFTWARE GUIDES - 9. Driver488/SUB
II-156 Personal488 User’s Manual, Rev. 3.0
/* Reset the buffer pointer of the ADC488 */
Output(adc, “B0X”);
Next, we fill the buffer with 100 readings from the ADC488. Since the data being returned from the
ADC488 is in a binary format, the
noterm terminator structure is used to disable scanning for
terminators such as carriage-return and line-feed:
noterm.EOI=0 ;
noterm.nChar=0 ;
EnterX (adc, (char*) hundred,200,1,¬erm,1,0L) ;
The EnterX function will use a DMA transfer if available. Because DMA transfers are performed
entirely by the hardware, the program can continue with other work while the DMA transfer function
occurs. For example, the program will process the previous set of data while collecting a new set of
data into a different buffer. However, before processing the data we must wait for the transfer to
complete. For illustration purposes, we query the Driver488/SUB status both before and after waiting.
/* Display DRIVER488/W31 status */
Status (ieee,&substat) ;
showstat (&substat) ;
/* Wait for completion of input operation*/
Wait (adc) ;
/* Display DRIVER488/W31 status */
Status (ieee,&substat) ;
showstat (&substat) ;
Now we process the buffer:
/* Print the received characters */
for (i=0;id;i++) {
printf (“%6d”,hundred [i]) ;
if ((i%10)==9)
printf (“\n”) ;
}
The functions described so far in this Sub-Chapter provide enough functionality for a basic data
acquisition program. The following program listing covers the examples used. Additional functions
provided by Driver488/SUB are described in the “Section III: Command References” of this manual.
Sample Program
#include
#include
#include
#include”iot_main.h”
#include”iottx10.h”
void showstat (IeeeStatusT*) ;
void isr (OpaqueP) ; /*handle inerrupt*/
DevHandleT adc,ieee,dev;
int hundred[100] ;
void main ( )
{
char response [256] ;
int i;
float voltage,
sum;
IeeeStatusT substat ;
/*establish communications with Driver488/SUB*/
if ((ieee=OpenName (“IEEE”))==-1) {
printf (“Cannot initialize IEEE system.\n”) ;
exit (1) ;
}