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July 2006, Part Number 370960C-01

Use the FPGA Interface functions to communicate with an FPGA VI from a host VI. The VI that runs on an FPGA target is called the FPGA VI. A host VI is a VI that communicates with the FPGA VI to control the FPGA target. A host VI can run on a Windows computer or on an RT target.

You can use the FPGA Interface functions to programmatically control and communicate with an FPGA VI. Use the FPGA Interface functions to perform the following operations in host VIs:

• Establish and terminate communication with the FPGA VI.
• Download, abort, reset, and run the FPGA VI on the FPGA target.
• Read and write data to the FPGA VI.
• Wait for and acknowledge FPGA VI interrupts.
• Read DMA FIFOs.

Note  This palette is available only when you edit a VI under My Computer or an RT target in the Project Explorer window.

The functions on this palette can return general LabVIEW error codes, specific FPGA Interface error codes, or error codes specific to the FPGA target. Refer to the specific FPGA target documentation for a list of target-specific error codes.

Palette Object	Description
Call VI	Allows you to call a compiled FPGA VI as a subVI from a host VI. Use the Call VI function to communicate with front panel objects in the FPGA VI. The Call VI function downloads the FPGA VI to the FPGA target unless the FPGA VI already has been downloaded to the target. Some FPGA targets might not support the Call VI function. Refer to the specific FPGA target hardware documentation for information about support of the Call VI function.
Close FPGA VI Reference	Stops and resets the FPGA VI running on the FPGA target and closes the reference to the VI. Right-click the Close FPGA VI Reference function on the block diagram and select Close from the shortcut menu to close the reference without resetting the FPGA VI running on the FPGA target. The default is Close and Reset, which closes the reference, stops the FPGA VI, and resets the FPGA VI running on the FPGA target.
Invoke Method	Invokes an FPGA Interface method or action from a host VI on an FPGA VI. Use methods to do the following: download, abort, reset, and run the FPGA VI on the FPGA target, wait for and acknowledge FPGA VI interrupts, read DMA FIFOs, and write to DMA FIFOs. The methods you can choose from depend on the target hardware and the FPGA VI. You must wire the FPGA VI Reference In input to view the available methods in the shortcut menu.
Open FPGA VI Reference	Opens a reference to the FPGA VI or bitfile and FPGA target you select in the shortcut menu or that you specify with the resource name input. You must open a reference to the FPGA target before you can communicate between the host VI and the FPGA VI.
Read/Write Control	Reads a value from or writes a value to a control or indicator in the FPGA VI on the FPGA target.
Up Cast	Converts an FPGA VI-specific reference to a more generic reference. You then can use common code to interact with different FPGA VIs. The FPGA targets must be of the same class. You might want to use this function if you want to evaluate different algorithms in a host VI without rewriting the host VI. You cannot use this function with DMA FIFOs. Some FPGA targets might not support this function. Refer to the specific FPGA target hardware documentation for more information.

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