how firmware VISA basedcan pay advantage of fast data streaming of PCIe/PXIe plaform

[Firmware_programmer]

Hi

    I know this white paper! this is not the first driver that I write. The precedents was for PLX9030. This was a more simple works because in PCI/PXI bridge without DMA or other possibilities and then with moveInXX and moveOutxx was suffisant...(with openSession and close!)

 But this time is with PEX8311 and it is more complicated! 

I receive from PLX a SDK and I need to study his driver to sucess to write a NI VISA driver. To explain to wizard how to work I need to understand better the chip and as perhaps I should have the good questions to ask....

Thanks for your help

Dina

[toshas]

Hello!

Do you have any success ?

I'm working on the same field but I couldn't get high-speed transfer until now.

I created driver as mentioned in http://www.ni.com/white-paper/4713/en white-paper.

But this white-paper has no information about DMA.

So I can get 20Mbytes/s for write-transfer and 2Mbyte/s for read-transfer.

(viMoveInxx/viMoveOutxx functions and Peek/Poke on mapped region gives almost the same results.)

All transfers has 1DW length (simple PIO interface).

Screenshots of pcie transactions on TLP level are included.

I marked SOF/EOF and time stamp (1clk = 16ns).

This is definitely not DMA(

Also I tried set attribute "Allow DMA transfer" but got an error "is not defined or supported".

Waiting for the help!

[JoeySpinella]

I am not sure that the scope of the VISA driver development wizard allows us to configure DMA access.

Have either of you looked into using the NI Measurement Hardware DDK (Driver Development Kit)?

http://sine.ni.com/nips/cds/view/p/lang/en/nid/11737

This gives us register level programming examples to control DMA functions on NI and possibly third-party hardware.

http://digital.ni.com/public.nsf/allkb/1C3988D7D33B925C86256C59007FB4B4?OpenDocument

It may also be worth checking out the Driver Development Kit forum:

http://forums.ni.com/t5/Driver-Development-Kit-DDK/bd-p/90

[Firmware_programmer]

Hi

   I use the DDK is a great idea! I success to work with DMA. I do not test performance already ( I work with an evaluation board now) but this is suffisant for a first try!

   Thanks

Dina

[toshas]

Hello!

J_spin, thanks!
I will look into this direction (DDK).

Firmware_programmer, could you please share your DMA solution (or maybe just briefly description of performed steps)?
Are there any "hidden dangers" ?

thanks a lot!

[Firmware_programmer]

HI

I attached my first try. I is a single DMA transfer. This week I will continue... Check Burst possibilities, and Scatters/gathred mode...

Good luck

Dina