Pulse Generation using USB port alone.

[jj@IIT]

Hi,

I want to generate a sequence of digital pulses .(5 pulses @5MHz..repeated at every 1ms). I can genertae the sequence in LabVIEW.

Is there any way in which I can output these pulses via the USB port ?. I mean, I am not connecting any USB device at the port. I just want to use the data lines for sending theses digital pulses to a driver circuit.

 All tutorials I found talk about installing drivers...for device communication.

What I want is to just use the USB port (just like a normal serial port) and send some data (pulse patterns) out.

Thanks in advance

[Intaris]

99.99% sure the answer is no.

Shane.

[smercurio_fc]

Actually, the answer is yes and no. Yes in the sense that you can program the USB to generate data. No in the sense that you cannot control it with the precise timing that you want. You're better off getting a DIO card or module. An analog output would work also.

[jj@IIT]

I understand that there may be timing issues...but I stil want to give it a try(may be using timed loops etc). Could you inform me , how to program the USB port to genrate data without connecting any device to the port..Say if I genrate a bit sequence in LV..how can I output it via the USB port..?

[smercurio_fc]

Frankly, I think you're barking up the wrong tree. The USB port was simply not designed to do this. Besides, you cannot implement accurate timing control with a non-real-time operating system. My statement "you cannot control it with the precise timing that you want" was referring to this, and had nothing to do with USB. I think your time would be better spent tracking down a device that's designed for this purpose.

If you want to even try it, it's your time. At the very minimum you would need to do USB RAW communication. In LabVIEW that uses VISA, so this means that you need some kind of device driver so that you can create a VISA session. You can read about USB RAW in the following KB articles:

How Can I Communicate With a Device Using NI-VISA USB RAW Mode?

What is the Difference Between USB Raw Control and USB Raw Bulk?

Don't say I didn't warn you.

[jj@IIT]

Warning heeded!!!Thank you for the links. I have already implemented the pulse generation using a PXI 6602 counter timer card. It meets my requirements.

I just thought of trying out an alternative without using specific hardware. Thanks again for the advice..