FIFO to DMA setting for Read/Write

[thej178]

Hello, I am following an example I found on eetimes (.com), title: FFTs in LabVIEW FPGA. In their example, they only provide the Data Acquisition Loop and Processing Loop screenshots, no information about how they create their FIFO. I am pretty new to LabVIEW FPGA. I am trying to recreate this example and created a FIFO FPGA to Host with Target to host - DMA general property. This is because I know we will want our input to be stored this way. 

In their example, they use the DAQ FIFO with both the read and write FIFO method node. I am not able to do this with my FIFO which I am sure is because the general property I set. How should I create a FIFO so that I can both read and write from it?

Update:

I see that changing Host to Target type to Target-Scoped type allows for FIFO read/write. How could I read from a Host to target DMA type of a FIFO? Is there a way to do this?

[RavensFan]

You create in the Project Explorer.  Right click on the FPGA under the project tree and pick New ....  FIFO.

[cbutcher]

A "target-scoped" FIFO is a FIFO defined on the target (i.e. FPGA). It can be used to pass data between loops, VIs, frames etc on the FPGA.

A "Host to Target" or "Target to Host" DMA FIFO is defined between the host (e.g. cRIO) and target (FPGA). It only allows one way (depending on type) communication. So you'd need two (one Host to Target, one Target to Host) to have bi-directional FIFO communication between the RT system and the FPGA.

Additional information about the FIFO types can be found here: Transferring Data between Devices or Structures Using FIFOs (FPGA Module) and in related links.