National Instruments NI-VXI - Manual (Page 22)

Chapter 2 Introduction to the NI-VXI Functions
© National Instruments Corporation 2-3 NI-VXI User Manual
of the VXI/VME interrupt lines, VXI TTL triggers, VXI ECL
triggers, and utility bus signals. The National Instruments Resource
Manager configures the mainframe extenders with settings based on
user-modifiable configuration files.
VXI-Only Function Groups
The following NI-VXI function groups do not apply to VME.
• Commander Word Serial Protocol Functions—Word Serial is a
form of communication between VXI message-based devices. The
Commander Word Serial functions give you the necessary
capabilities to communicate with a message-based Servant device
using the Word Serial, Longword Serial, or Extended Longword
Serial protocols. These capabilities include the sending of
commands and queries and the reading and writing of buffers.
• Servant Word Serial Protocol Functions—Servant Word Serial
functions allow you to communicate with the message-based
Commander of the local CPU (the device on which the NI-VXI
interface resides) using the Word Serial, Longword Serial, or
Extended Longword Serial protocols. These capabilities include
command/query handling and buffer reads/writes.
• VXI Trigger Functions—The VXI trigger functions let you source
and accept any of the VXIbus trigger protocols. The actual
capabilities available depend on the specific hardware platform.
The VXI trigger functions can install handlers for various trigger
interrupt conditions.
Calling Syntax
The interface is the same regardless of the development environment or
the operating system used. Great care has been taken to accommodate
all types of operating systems with the same functional interface
(C/C++ source-level compatible), whether it is non-multitasking (for
example, MS-DOS), cooperative multitasking (such as Microsoft
Windows 3.x or Macintosh OS), multitasking (for example, UNIX,
Wndows 95, or Windows NT), or real-time (such as LynxOS or
VxWorks). The NI-VXI interface includes most of the mutual
exclusion necessary for a multitasking environment. Each individual
platform has been optimized within the boundaries of the particular
hardware and operating system environment.