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Chapter 3 Software Overview
NI-VXI User Manual 3-54 © National Instruments Corporation
Embedded, External MXI-2, and Remote
Controller Trigger Capabilities
National Instruments has developed a highly functional ASIC
specifically designed for use within the VXIbus triggering environment
called the Trigger Interface Chip (TIC).
Note:
In MXI-2 and the latest embedded systems, the TIC has been incorporated
into the MANTIS ASIC.
The TIC chip has access to all of the eight VXI TTL trigger lines,
two ECL trigger lines (ECL0 and ECL1), and 10 external or
General-Purpose Input/Output (GPIO) connections simultaneously.
The TIC also contains a 16-bit counter and a dual 5-bit scaler tick
timer. It contains a full crosspoint switch for routing trigger lines and
GPIOs (as well as the counter and the tick timers) between one another.
If you want more information on triggering or if you plan to use any of
the advanced features of the TIC, please contact National Instruments
for the technical note, Triggering with NI-VXI.
Acceptor Trigger Functions
The NI-VXI acceptor trigger functions act as a standard interface for
sensing (accepting) TTL and ECL triggers, as well as for sending
acknowledgments back to the sourcing device. These functions can
sense any of the VXI-defined trigger protocols on the local
embedded controller or external extended controller(s). Use the
EnableTrigSense
function to prepare for the sensing of any of the
trigger protocols. If the protocol requires an acknowledgment, you
should call the
AcknowledgeTrig
function when appropriate. You
can use
SetTrigHandler
to install a callback handler for the
specified trigger line. A default handler,
DefaultTrigHandler
, is
installed for each one of the trigger lines when
InitVXIlibrary
is called and will call
AcknowledgeTrig
for you. You can use the
SetTrigHandler
function at any time to replace the default handlers.
In addition, you can use the
WaitForTrig
function to accommodate
applications that do not want to install callback handlers.