Serial output on single digital line (USB-6251)

[Stu-Qub]

Hi

I am trying to output an 8 bit word serially on a single digital line (eg Port 0, line 0) on the USB-6251. I need this as I need to control devices using the SPI interface. I have so far only managed to output the data across the whole port (parallel).

Is this possible to achieve?

I am using Labview 8.5 and Windows XP

Thanks

Stuart

Message Edited by Stu-Qub on 07-29-2008 09:34 AM

[Stu-Qub]

Anybody??

[Rich_Silley_NIUK]

Hi Stuart

You will have to forgive me as I myself do not have any experience with the SPI protocol but you should be able to implement this with the 6251.

If you have a look on this forum post you will find an example of how to implement this. One thing to keep in mind is the example is only software timed and the fastest software-timed SPI clock rate is 1 kHz. Therefore if the SPI device you want to communicate with needs to have a high communication speed this will not be able to communicate fast enough. Port 0 of your 6251 does support hardware timed DIO which will enable you to communicate faster. The DI Sample Clock frequency range for the usb device is 0-1 MHz. The DO Sample Clock frequency is 0-10MHz if you are regenerating the sample from the on-board FIFO 0-1 MHz.

I hope this helps. Let me know if you have any more questions.

Rich
NI | UK

[Stu-Qub]

Thanks. That was exactly what I needed.