Re : FPGA card 7811R/7813R with optical link 8375

[sfla]

Hello, I have a PXI package with FPGA card 7811R/7813R. This PXI package is connected to a pc via the optical link 8375.
I would like to know if it is possible to drive some FPGA output with the PC. The other output are driven by the software build with FPGA module LabVIEW.

Thanks

[benoitsimon]

Hi sfla,

If I understood correctly, you want to have acces to the I/O of your FPGA without programming the FPGA ?

I'm sorry but this is not possible with the PXI boards.

Regards,

[sfla]

In fact, I have a FPGA software in the 7811R which drives some outputs. The 7811R is in a "chassis" with the 8375 card (optical link) connected to a pc. The pc will run a labwindows software with switch to drive an output. Is this output can be a 7811R output ?

[sfla]

Another question  about optical link. What can I do with this on 7811R ? With the pc, can I read Input and Output of the 7811R ? 

Thanks a lot.

[benoitsimon]

It depends on how the FPGA software has been developped.

From your LabWindows Software, you can drives the outputs and read the inputs of your FPGA board. You have to use Variables or DMA FIFOs in order to do this.

[sfla]

In fact here is the details.

We need 2 functional mode.

First mode:
- A FPGA software manage some outputs with logic downloaded with LabVIEW FPGA Module
- A LabWindows software run on a PC connected with the optical link to the PXI chassis with 7811R
This LabWindows software shall be able:
- to drive some outputs of 7811R
- to read the other outputs of 7811R
- to read the input of 7811R

Second mode:
- The FPGA software is in "idle" mode
- As the FGPA software is in "idle" mode, the LabWindows software shall be able:
- to drive all outputs of 7811R
- to read the input of 7811R

Could you please tell me what is possible : first mode, second mode ?

Can you give me details about Variables or DMA FIFOS you speak about ?

[benoitsimon]

The 2 modes are possible.

The trick is that you will always need the FPGA code to run. On the first mode, you will have some logic implemented, and on the second mode you will use FIFO DMA to pass the data to your host (or to your target if you want to write on the outputs).

You have to create the FPGA in LabVIEW FPGA, and then read/write on the CVI part.

Regards,

[sfla]

Thanks for your answer.

If I understood, I need 2 different software in the FPGA. One for first mode, another for second mode.

It would be more convenient to have only one FPGA software which can manage the 2 modes. I think it will be possible to select the mode with a switch in the pc LabWindows software, this switch through DMA FIFO will set the mode inside the FPGA software. Do you think it is possible ?

[benoitsimon]

Hello sfla,

The code that you will download to your FPGA target is called a bitfile.

I don't know if you can implement the 2 modes in the same bitfile, it depends on the architecture of your code.

However, from your host part in LabVIEW (might probably be the same in CVI), you can use the fonction Open FPGA VI Reference to download the bitfile automatically to your FPGA target.

So you can use a switch to download the bitfile you want in your host application.

Before starting your project, it might be interesting to follow the FPGA course that we are teaching. You should contact the branch of your country to order and register to this course 😉

Regards,

[sfla]

Hi, I think it is possible to have the 2 modes in the same bitfile.

Do you agree with this :

A switch in a LabWindows software will select the functionnal mode, mode 1 or mode 2. The FPGA bitfile read the value of the switch via FIFO DMA. According to this value, the bifile set the output of the FPGA according logic bitfile or according value of other switch in LabWindows software (also read by bitfile with FIFO DMA).

What do you think about that ?