Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi - Manual (Page 176)

II. SOFTWARE GUIDES - 9. Driver488/SUB 9F. QuickBASIC
Personal488 User’s Manual, Rev. 3.0 II-161
Driver488/SUB, to clone a new device called ADC using the MakeDevice command. Lastly, the IEEE
bus address 14 is assigned to the ADC .
adc% = ioOpenName% (“ADC”)
IF (adc% = 1) THEN
response$ = SPACES (256)
rv% = ioGetError% (ieee%, response$)
dev% =ioOpenName% (“DEVIEEE”)
adc% = ioMakeDevice% (dev%,”ADC”)
rv% = ioBusAddress% (adc%,14,-1)
END IF
If other devices were needed for the application at hand, they could either be defined in the startup
configuration for Driver488/SUB or they could be created on the fly from the application:
adc2% = ioMakeDevice% (adc%,”ADC2”) ; /*Clone a new device */
rv% = ioBusAddress% (adc2%,10,-1) ; // Set the bus address
The new device ADC2 is configured to reside at a different bus address so that the two devices may be
distinguished. There is one other important difference between ADC and ADC2 at this point. ADC2 is a
temporary device; that is, as soon as the creating application closes, ADC2 ceases to exist. If our intent
was to create a device that could be accessed after this application ends, we must tell Driver488/SUB
this:
rv%=ioKeepDevice% (adc2%) ;
After executing the above statement, ADC2 is marked as being permanent; that is, the device will not be
removed when the creating application exists. If we later wish to remove the device, however, we can
do so explicitly:
rv%=ioRemoveDevice% (adc2) ;
Confirming Communications
With or without an open device handle, the application can, if desired, confirm communication with
Driver488/SUB via the
Hello function:
The function also fills in a string from which information can be extracted if it is desirable to display
facts about the driver in use:
Setting Up Event Handling
If the event notification mechanism of Driver488/SUB is to be used, it should normally be set up
during application initialization and left in place until application shutdown. No special action is
required if event notification is not needed for the particular application. First, the
ONPEN GOSUB and
PEN ON functions establish the notification path by specifying the function to be called:
ON PEN GOSUB isr
PEN ON
rv% = ioLightPen% (ieee%, 1)
Either during initialization or at some appropriate later point in the application, specific event types
may be
Arm ed or Disarm ed for use in the event system. Individual event types may be turned on and
off at will freely through the life of the application. In this case, we Arm to request notification of
IEEE 488 bus service requests:
rv% = ioArm% (ieee%, acSRQ)
To cease recognizing bus service requests, we might Disarm just the one class of events:
rv% = ioDisarm% (ieee%, acSRQ) ;
Or, to completely disable event notifications:
response$ = SPACES (256)
rv% = ioHello% (ieee%,response$)
PRINT response$