BASICA/QuickBASIC GPIB-PC Function Calls Section Four AGPIB-PC User Manual 4A-42 ©National Instruments Corp.BASICA/QuickBASIC BASICA/QuickBASICIBPAD IBPADPurpose: Change Primary AddressFormat: CALL IBPAD (BD%,V%)Remarks: BD% specifies a device or an interface board. V% specifiesthe primary GPIB address of the device or interface board.IBPAD is needed only to alter the value from itsconfiguration setting.Only the low five bits of V% are significant and they mustnot all be ones. Thus there are 31 valid GPIB addresses,ranging from 0 to &H1E. An EARG error results if thevalue of V% is not in this range.The assignment made by this function remains in effectuntil IBPAD is called again, the IBONL or IBFINDfunction is called, or the system is rebooted.When IBPAD is called and an error does not occur, theprevious value of ist is stored in IBERR%. The previousprimary address is returned in IBERR%.Device IBPAD Function:When BD% specifies a device, IBPAD determines the talk and listenaddresses based on the value of V% for use in all I/O directed to thatdevice. A device listen address is formed by adding &H20 to theprimary address; the talk address is formed by adding &H40 to theprimary address. Consequently, a primary address of &H10 correspondsto a Listen address of &H30 and a talk address of &H50. The actualGPIB address of any device is set within that device, either withhardware switches or a software program. Refer to the devicedocumentation for instructions.Board IBPAD Function:When BD% specifies a board, IBPAD programs the interface board torespond to the primary talk and listen address indicated by V%.Refer also to IBSAD, IBONL, and Table 2.1.
