Maximum number of FIFO from host to target

[Amit Ahuja]

Hi 

I have vi on the RT from which i want to pass 32 clusters to the  FPGA vi parallely,

I have gone through material related to FPGA and found that the best way to pass

the data b/w the RT and FPGA is to have DMA FIFOs, but is it good to use 32 different

FIFO'S for each of 32 clusters or should i use control such array of clusters or clusters

to pass the data. As i am new to this field i am not able to decide which is the better way

of doing it 🙂

I have teh following configuration with me(RIo0 ,PXI 7831-R)

Regards

Amit Ahuja

[TurboTurtle]

Hello Mr.Amit,

Yes, you have heard right, the best way to transfer data between RT and FPGA is through FIFOs. But you cannot create 32 FIFOs as the number of DMA channels available for transfer is only 3. Moreover, you can only input a single element into a FIFO. So the best way, according to me, would be to create an array of 32 elements, put them into a for loop and enable indexing and write them into a DMA target to host FIFO. This would give you 32 interleaved samples, which you can extract in your RT VI.

Vishal

Applications Engineer

National Instruments

[Amit Ahuja]

Hi , Vishal Thanks for the valuable information. Actually what i want to pass information from the RT to FPGA. My requirement is that i have 32 arrays of 14 bytes (size of each frame) that i need to pass to the FPGA parallely and asynchronously ,so as to extract the data and arbitrate upon it. Can anyone help me as it is an urgent requirement.....:) Regards Amit Ahuja

[TurboTurtle]

Hello,

So, the best solution for this would be to make an array of these 32 arrays ( i.e. a 2D array) and put it in 2 for loops and read it into a FIFO. This would be a host to target DMA FIFO.

And in your FPGA VI, you would read this, put it into seperate arrays as and when you read the data.

Vishal Barfiwala

Applications Engineer

National Instruments

[Amit Ahuja]

Hi Vishal Thanks For the useful input :) I forgot to add an important point to it That if one array is arbitrated i again to rad to all the 32 arrays to arbitrate on that so can i do that using a fifo as fifo needs th contain th snapshot of all the 32 arrays after arbitrating among the arrays. If i use controls then how much the overhead increases Regards Amit