My PCI device can't get a high Communications speed with ni-visa

[FTLiang]

Dear Everybody,

I have design a PCI card for a high speed data readout. My PCI card use PCI9054 as the PCI interface. And I have tested it with plxmon(plx sdk from plx Company), with DMA, DirectSlave can get a high speed (40~90MB/s) except read from device(3MB/s).

But when I try to use NI-VISA to communicate with my pci card, read speed is 3MB/s and 20MB/s for write.

This speeds are unacceptable. I have search the visa help, and try all function but only get the same result.

The visa do not use the DMA model at all, and even do not uss the burst model for a high speed.

I want to know how to use the visa to communicate with my pci card at a high speed, and is there already a speed test result on pci device using visa?

And why I can only get a 3MV/s read out speed?

Thank you everybody, I have been troubled by the speed problem for weeks.

Futian Liang

China

[Lars.B]

Hello Futian,

have you tried also with VISA in synchronous mode? 

I've got a similar problem with data rate and my solution was to put VISA in this mode (default mode is asynchronous). To do so, right click on the Read/Write-VIs and choose the appropiate mode.

Second point: DMA transfer is maybe possible. There is a setting in property-node, General settings:Allow DMA transfers

Greets,

Lars

Message Edited by Lars.B on 08-28-2009 09:02 AM

Message Edited by Lars.B on 08-28-2009 09:04 AM

[FTLiang]

Thanks for you help Lars,

I had used viMove (CVI code) to read or writ, and it seems default mode is already synchronous, because there is a viMoveAsyn function with Asynchoronous.

And I tried viMoveAsyn too, and my device do not support this mode.

The General settings : Allow DMA transfers is unsetable for my device....

With these days research, I have learned my pci interface chip could do the DMA function just by setting its registers. But the bad news is every time I set the right parameters(it should be right), the DMA transfers by the interface chip operates the wrong PCI Address(memory address in PC), and my computer crash down...

[Jian.T]

hello,I have the same problem with you,and I want to ask you some question. May have your Email?

My Email is 229522890@qq.com.

[FTLiang]

Send you an email for further info.

[Pie566942.0]

Hi,

Can you share any more information on this topic?  I am finding gross PCI bandwidth imitations with VISA 5.4.0.

Thanks