National Instruments NI-VXI - Manual (Page 38)

Chapter 2 Introduction to the NI-VXI Functions
© National Instruments Corporation 2-19 NI-VXI User Manual
Note: Although NI-VXI simplifies the installation and use of callback handlers,
it cannot affect how the system handles interrupts. The programmer must
follow programming guidelines set by the chosen operating system. Some
of these guidelines could include using only reentrant functions, adhering
to timing restrictions, and on Macintosh computers, regaining access to
global variables.
Triggers
The addition of trigger lines to the VMEbus is one improvement the
VXIbus has over VME in the field of instrumentation. To take
advantage of this feature, NI-VXI has a wide selection of functions you
can use to set up your controller to both source and acknowledge
trigger lines. The TIC is a National Instruments ASIC (Application
Specific Integrated Circuit) that gives you the capability to map trigger
lines to trigger lines as well as to external lines, use special
counter/timers, and monitor multiple trigger lines simultaneously.