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Transferring Data Using Front Panel Controls and Indicators (FPGA Module)

LabVIEW 2013 FPGA Module Help

Edition Date: June 2013

Part Number: 371599J-01

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Use the Read/Write Control function in a host VI to access the front panel controls and indicators of the FPGA VI, as shown in the following block diagram.

Note  Support for programmatic front panel communication varies by FPGA target. Refer to the specific FPGA target hardware documentation for more information.

An advantage of programmatic front panel communication relative to other methods of transferring data between the FPGA and the host is its low overhead. Although you cannot attain high throughput with programmatic front panel communication, each call to the Read/Write Control function initiates data transfer with minimal delay. Therefore, programmatic front panel communication is ideal for small, frequent data transfers.

A disadvantage of programmatic front panel communication is that this method transfers only the most current data stored on the control or indicator of the FPGA VI. For example, data could be lost if the FPGA VI writes data to an indicator faster than the host VI can read the data. Also, each control or indicator on the FPGA VI uses resources on the FPGA. Best practices in FPGA programming recommend limiting the number of front panel objects in FPGA VIs. Finally, transferring data between the FPGA VI and the host VI using front panel controls and indicators requires the use of the host processor. As a result, the speed of data transfer is highly dependent upon the speed and availability of the host processor. A slower processor or lack of processor availability results in slower data transfer from the FPGA target to the host.


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