GET_DEVICE_DESCRIPTOR

[shoneill]

I've been trying to get some basic USB communication working under LV 8.2.1.

I've created and installed the custom system driver generated by the driver wizard, and everything seems to be OK there.

I've also downloaded and read up on the USB specification a bit.

I thought I'd try communicating with the device by performing a "GET_DEVICE_DESCRIPTOR" request, which according to USB specification, the instrument must at all times respond to.

I have wired up the functions "VISA USB Cpontrol out" and "VISA USB Control in" as I think they should be wired, but it's not working, plain and simple. I'm getting "Invalid buffer mask" errors for the settings I thought were correct for the communication.

Using a USB sniffer, I see that I am able to provoke the communication, but I'm not able to get any data back. I'm also getting some unexpected error messages.

I've already posted here on the NI forum.

Could anyone here please help me out with what surely can't be too difficult a task. I AM a total beginner with USB communication so please go easy on me

Shane.

[Tom Limerkens]

Hi Shane,

If I were you, check out the following articles on RAW USB communication using VISA.

There are the very basics of how to communicate with a USB device, and also the different

ways how to communicate, Interrupt, Bulk, etc...

http://zone.ni.com/devzone/cda/tut/p/id/4478

http://digital.ni.com/public.nsf/allkb/E3A...6256DB7005C65C9

http://digital.ni.com/public.nsf/allkb/1AD...6256ED20080AA3C

http://zone.ni.com/devzone/cda/epd/p/id/3622

If you have control, or knowledge about the USB device's code, that will make it a easier.

Hope this helps ?

Tom

[shoneill]

QUOTE(Tom Limerkens @ Nov 1 2007, 03:03 PM)

Hi Shane,

If I were you, check out the following articles on RAW USB communication using VISA.

There are the very basics of how to communicate with a USB device, and also the different

ways how to communicate, Interrupt, Bulk, etc...

http://zone.ni.com/devzone/cda/tut/p/id/4478

http://digital.ni.com/public.nsf/allkb/E3A...6256DB7005C65C9

http://digital.ni.com/public.nsf/allkb/1AD...6256ED20080AA3C

http://zone.ni.com/devzone/cda/epd/p/id/3622

If you have control, or knowledge about the USB device's code, that will make it a easier.

Hope this helps ?

Tom

Thanks Tom, but I've already done that. The articles are very superficial at best. What I need is a SINGLE wired-up example of a standard USB CONTROL communication (i.e. GET DEVICE DESCRIPTOR).

The example you linked is only for BULK transfer. I need CONTROL transfers to know how to wire up the "VISA USB Control in" and out functions.......

Shane.

[ttkx]

If you want to get "GET DEVICE DESCRIPTOR",you can use setup package by standard request. sure,by CONTROL transfers . I guessed you already creat driver by VISA Driver Development Wizard.

[shoneill]

QUOTE(ttkx @ Nov 2 2007, 02:16 AM)

If you want to get "GET DEVICE DESCRIPTOR",you can use setup package by standard request. sure,by CONTROL transfers . I guessed you already creat driver by VISA Driver Development Wizard.

ttkx,

Perfect! This is eactly what I was looking for.

I'll be able to use this as a proper starting point to find out how the USB commands as described in the USB spec are to be handled within LabVIEW.

Judging by the values you're feeding to the "VISA USB Control in", I have clearly misunderstood some of the parameters within the USB spec.....

Shane.