BASICA/QuickBASIC GPIB-PC Function Calls Section Four AGPIB-PC User Manual 4A-34 ©National Instruments Corp.BASICA/QuickBASIC BASICA/QuickBASICIBGTS IBGTSPurpose: Go from Active Controller to StandbyFormat: CALL IBGTS (BD%,V%)Remarks: BD% specifies an interface board. If V% is non- zero, theGPIB-PC shadow handshakes the data transfer as anAcceptor, and when the END message is detected, theGPIB-PC enters a Not Ready For Data (NRFD) handshakeholdoff state on the GPIB. If V% is zero, no shadowhandshake or holdoff is done.The IBGTS function causes the GPIB-PC to go to theController Standby state and to unassert the ATN signal ifit initially is the Active Controller. IBGTS permits GPIBdevices to transfer data without the GPIB-PC being a partyto the transfer.If the shadow handshake option is activated, the GPIB-PCparticipates in data handshake as an Acceptor withoutactually reading the data. It monitors the transfers for theEND (EOI or end-of-string character) message and holds offsubsequent transfers. This mechanism allows the GPIB-PCto take control synchronously on a subsequent operationsuch as IBCMD or IBRPP.Before performing an IBGTS with shadow-handshake, theIBEOS function should be called to establish the properend-of-string character or to disable EOS detection if theend-of-string character in use by the talker is not known.The ECIC error results if the GPIB-PC is not CIC.Refer also to IBCAC.In the example that follows, GPIB commands andaddresses are coded as printable ASCII characters. Whenthe hex values to be sent over the GPIB correspond toprintable ASCII characters, this is the simplest means ofspecifying the values. Refer to Appendix A for conversionsof hex values to ASCII characters.
