Chapter 5
S Mode Functions — gts
©
National Instruments Corporation
5-17
gts
Go from Active Controller to Standby
Type
Low-level bus management function
Syntax
gts [bool]
<CR>
Purpose
You can use
gts
to change the GPIB-232/485CT-A from Active Controller to Standby
Controller. Use
gts
when the I/O and high-level bus management functions do not meet the
needs of your device.
gts
permits GPIB devices to transfer data without the GPIB-232/485CT-A participating in
the transfer. For example, you can use
gts
if you want to let two external devices talk to each
other directly. The GPIB-232/485CT-A can selectively participate in the handshake of the
data transfer and hold off the handshake when it detects the END message. The
GPIB-232/485CT-A can then take control synchronously without possibly corrupting the
transfer.
Remarks
If the argument
bool
is 1, shadow handshaking is enabled. If the argument
bool
is 0, shadow
handshaking is not performed.
gts
causes the GPIB-232/485CT-A to go to the Controller Standby state and to unassert the
ATN* signal if it is initially the Active Controller.
If you enable shadow handshaking, the GPIB-232/485CT-A participates in the 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-232/485CT-A to take control synchronously on a subsequent
operation such as
cmd
or
rpp
.
Before performing a
gts
with a shadow handshake, you should call
eos
to establish the
proper end-of-string character or to disable the EOS detection if the end-of-string character
used by the Talker is not known.
