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Chapter 1
Introduction
© National Instruments Corporation
1-5
Software accesses the R Series device through the bus interface. 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.
The FPGA does not retain the VI when the R Series device is powered off, 
so you must reload the VI every 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 the R Series device using a subset of LabVIEW 
functionality. Refer to the R Series examples, located in the 
<LabVIEW>\
examples\R Series
 directory, for examples of FPGA VIs.
Software Development
You can use LabVIEW with the LabVIEW FPGA Module to program the 
NI 781xR. To develop real-time applications that control the NI 781xR, 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 device. Use the FPGA Module VIs