National Instruments NI-VXI

Chapter 2 Introduction to the NI-VXI Functions

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.