Measurement Computing GPIB-488 - Manual (Page 35)

Chapter 3 GPIB 488.1 Library Reference
Programming Reference Manual 3-22 GPIB-488
IBGTS
Puts an Active Controller in Standby mode.
Syntax
C ibgts (int board, int handshake)
Parameters
board is an integer containing the board handle.
handshake determines whether or not the shadow handshake option is to be activated. If
handshake is non-zero, then the GPIB shadow handshake option is activated. This means
that the GPIB board shadow handshakes the data transfer as an acceptor and when the END
message is detected, the GPIB board enters a
Not Ready For Data (NRFD) handshake
hold-off state on the GPIB. Thus, the GPIB board participates in the data handshake as an
Acceptor without actually reading the data. It monitors the transfers for the
END message and
holds off subsequent transfers. Using this mechanism, the GPIB board can take control
synchronously on a subsequent operation like
ibcmd or ibrpp .
If handshake is 0, then no shadow handshake or holdoff is done.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA .
iberr will contain an error code, if an error occurred. The ECIC error occurs if the board is
not an Active Controller.
Usage Notes
This call makes the GPIB board go to Controller Standby state and unasserts the ATN line if
it is initially the Active Controller. This allows transfers between GPIB devices to occur
without the GPIB board's intervention.
Before performing an ibgts with a shadow handshake, use the ibeos function to
define/disable EOS character detection.
Example
This example uses the ibcmd routine to instruct GPIB board 1 to unlisten
all devices (ASCII ?, hex 3F), and then to address a Talker at MTA26
(ASCII Z, hex 5) and a Listener at MLA11 (ASCII +, hex 2B).
ibgts is
then called to unassert the ATN line and place the GPIB board in Standby
mode. This action allows the Talker to send messages to the Listener. Note
that the GPIB commands/addresses are coded using printable ASCII
characters, for example, "?Z+".