BASICA/QuickBASIC GPIB-PC Function Calls
Section Four A
GPIB-PC User Manual
4A-34
©National Instruments Corp.
BASICA/QuickBASIC
BASICA/QuickBASIC
IBGTS
IBGTS
Purpose:
Go from Active Controller to Standby
Format:
CALL IBGTS (BD%,V%)
Remarks:
BD%
specifies an interface board. If
V%
is non- zero, the
GPIB-PC shadow handshakes the data transfer as an
Acceptor, and when the END message is detected, the
GPIB-PC enters a Not Ready For Data (NRFD) handshake
holdoff state on the GPIB. If
V%
is zero, no shadow
handshake or holdoff is done.
The
IBGTS
function causes the GPIB-PC to go to the
Controller Standby state and to unassert the ATN signal if
it initially is the Active Controller.
IBGTS
permits GPIB
devices to transfer data without the GPIB-PC being a party
to the transfer.
If the shadow handshake option is activated, the GPIB-PC
participates in data handshake as an Acceptor without
actually reading the data. It monitors the transfers for the
END (EOI or end-of-string character) message and holds off
subsequent transfers. This mechanism allows the GPIB-PC
to take control synchronously on a subsequent operation
such as
IBCMD
or
IBRPP
.
Before performing an
IBGTS
with shadow-handshake, the
IBEOS
function should be called to establish the proper
end-of-string character or to disable EOS detection if the
end-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 and
addresses are coded as printable ASCII characters. When
the hex values to be sent over the GPIB correspond to
printable ASCII characters, this is the simplest means of
specifying the values. Refer to Appendix A for conversions
of hex values to ASCII characters.