National Instruments NI-VXI

Chapter 3 Software Overview

address space for the source and destination, respectively. The width

parameter selects either byte, word, or longword transfers. If one of the

addresses selected has no device residing at the address and a bus error

occurs, VXImove traps the bus error condition and indicates the error

through the return status.

VXIout (accessparms, address, width, value)

VXIout writes a single byte, word, or longword to a particular

VXI/VME address in one of the VXI/VME address spaces. The

parameter accessparms specifies the VXI address space, the VXI

privilege access, and the byte order to use with the access. The address

parameter specifies the offset within the particular VXI/VME address

space. The width parameter selects either byte, word, or longword

transfers. If the VXI/VME address selected has no device residing at

the address and a bus error occurs, VXIout traps the bus error

condition and indicates the error through the return status.

VXIoutReg (la, reg, value)

VXIoutReg writes a single word to a particular VXI device’s VXI

registers within the logical address space (the upper 16 KB of VXI

A16 address space). The function sets the VXI access privilege to

Nonprivileged Data and the byte order to Motorola. If the VXI address

selected has no device residing at the address and a bus error occurs,

VXIinReg traps the bus error condition and indicates the error through

the return status. This function is mainly for convenience and is a layer

on top of VXIoutLR and VXIout. If the la specified is the local CPU

logical address, it calls the VXIoutLR function. Otherwise, it calculates

the A16 address of the VXI device’s register and calls VXIout.

Note: VXIoutReg is designed to access a VXIbus device configuration register

and therefore is not applicable to VME devices.