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Acquire Write Region DMA FIFO (G Dataflow)

Last Modified: January 12, 2018

Requests a region to write to a Host to Target FIFO and returns an external data value reference to this region. Use this node to automatically begin DMA data transfer between the FPGA target and the host computer without using Start DMA FIFO.

Select the FIFO you want to use from the FIFO menu on the Item tab.

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reference in

Reference to an FPGA VI.

Obtain a reference using the Open FPGA VI Reference node.

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number of elements

Size of the buffer region this node acquires.

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timeout (ms)

Time, in milliseconds, that the node waits to complete before reporting a timeout error. Wire a value of –1 to this input to wait indefinitely.

Default: 5000

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elements in region

Total number of elements in the memory region this node acquires.

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error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

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reference out

Reference to an FPGA VI.

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write region reference

Reference to the array of elements the device driver allocates.

You must delete this external data value reference before the driver can read new data from the specified portion of the buffer.

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elements remaining

The number of elements in the host memory buffer that are available to write.

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error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application


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