multifunction-rio-user-manual.pdf - 第15页

Chapter 1 Introduction Multifunction Reconfigur able I/O User Manual 1-6 ni.com The FPGA does not retain the VI when the device is po wered of f, so you must reload the VI each time you po we r on the de vice. Y ou can l…

Chapter 1 Introduction

Reconfigurable I/O Architecture

Figure 1-1 shows an FPGA connected to fixed I/O resources and a bus

interface. The fixed I/O resources include A/D converters (ADCs),

D/A converters (DACs), and digital I/O lines.

Figure 1-1. High-Level FPGA Functional Overview

Software accesses the device through the bus interface, and the FPGA

connects the bus interface and the fixed I/O to make possible timing,

triggering, processing, and custom I/O measurements using the LabVIEW

FPGA Module.

The FPGA logic provides timing, triggering, processing, and custom I/O

measurements. Each fixed I/O resource used by the application uses a small

portion of the FPGA logic that controls the fixed I/O resource. The bus

interface also uses a small portion of the FPGA logic to provide software

access to the device.

The remaining FPGA logic is available for higher-level functions such as

timing, triggering, and counting. The functions use varied amounts of logic.

You can place useful applications in the FPGA. How much FPGA space

your application requires depends on your need for I/O recovery, I/O, and

logic algorithms.

FPGA

Bus Interface

Fixed I/O Resource

Chapter 1 Introduction

Multifunction Reconfigurable I/O User Manual 1-6 ni.com

The FPGA does not retain the VI when the device is powered off, so you

must reload the VI each time you power on the device. You can load the VI

from onboard Flash memory or from software over the bus interface. One

advantage to using Flash memory is that the VI can start executing almost

immediately after power up, instead of waiting for the computer to

completely boot and load the FPGA VI. Refer to the LabVIEW Help for

more information about how to store your VI in Flash memory.

Reconfigurable I/O Applications

You can use the LabVIEW FPGA Module to create or acquire new VIs

for your application. The FPGA Module allows you to define custom

functionality for your device using a subset of LabVIEW functionality.

Refer to the examples, available in LabVIEW by selecting Help»Find

Examples, and then selecting Hardware Input and Output»R Series, for

examples of FPGA VIs.

Software Development

You can use LabVIEW with the LabVIEW FPGA Module to program your

device. To develop real-time applications that control your device, use

LabVIEW with the LabVIEW Real-Time Module.

LabVIEW FPGA Module

The LabVIEW FPGA Module enables you to use LabVIEW to create VIs

that run on the FPGA of the R Series target device. Use the FPGA Module

VIs and functions to control the I/O, timing, and logic of your device and

to generate interrupts for synchronization. Select Help»Search the

LabVIEW Help to view the LabVIEW Help. In the LabVIEW Help, use the

Contents tab to browse to the FPGA Interface book for more information

about the FPGA Interface functions.

You can use Interactive Front Panel Communication to communicate

directly with the FPGA VI running on the FPGA target. You can use

Programmatic FPGA Interface Communication to programmatically

control and communicate with FPGA VIs from host VIs.

Use the FPGA Interface functions when you target LabVIEW for Windows

or an RT target to create host VIs that wait for interrupts and control the

FPGA by reading and writing the FPGA VI running on your device.

Chapter 1 Introduction

Note If you use the device without the FPGA Module, you can use the RIO Device Setup

utility, available by selecting Start»All Programs»National Instruments»

NI-RIO»RIO Device Setup to download precompiled FPGA VIs to the Flash memory of

the device. This utility installs with NI-RIO. You also can use the utility to configure the

analog input mode, to synchronize the clock on the device to the PXI clock (for PXI-78xx

only), and to configure when the VI loads from Flash memory. For more information about

using the RIO Device Setup utility, refer to the RIO Device Setup Help, found at Start»All

Programs»National Instruments»NI-RIO»

RIO Device Setup Help.

LabVIEW Real-Time Module

The LabVIEW Real-Time Module extends the LabVIEW development

environment to deliver deterministic, real-time performance.

You can write host VIs that run in Windows or on RT targets to

communicate with FPGA VIs that run on your device. You can develop

real-time VIs with LabVIEW and the LabVIEW Real-Time Module, and

then download the VIs to run on a hardware target with a real-time

operating system. The LabVIEW Real-Time Module allows you to use

your device in RT Series PXI systems being controlled in real time by a VI.

The PCI/PXI-781x is designed as a single-point DIO complement to the

LabVIEW Real-Time Module. The PCI/PCIe/PXI-783x/784x/785x is

designed as a single-point AI, AO, and DIO complement to the

LabVIEW Real-Time Module. Refer to the LabVIEW Help, available by

selecting Help»Search the LabVIEW Help, for more information about

the LabVIEW Real-Time Module.