LabVIEW
communication with USB Raw device
@Andrey Dmitriev wrote:
That could be great exercise...
That WOULD be a great exercise, but I don't see the *IDN? command anywhere in there, did you delete it from the document? 
@Dennis, I wholeheartily agree but something in my mind (the part that keeps reminding me of the limits of my knowledge) was telling me "Well, I sure don't think the *IDN? command is USB-standard and this guy seems crazy but hey, there are lots of things I'm not an expert on." I was doubting myself, but since someone else agrees with me either I'm not crazy or we're the same amount of crazy. My experience suggests the former may be the more likely.
Shane
Sure, you can communicate also with pendrive, but you need to recreate full communication protocol. Is your device uses the same communication protocol as pendrive? Sure, not. There are two modes for communication. Instead of using *IDN? command with pendrive you must use low level I/O, something like this (on given screenshot I perform communication with old USB Scanner):
Andrey.
USB is a layered protocol interface much like your network interface too. You have the electrical interface which is the USB connector. On top of that the USB communication which in its lowest incarnation is just a bunch of endpoints (addresses) that can be talked to.
This is what you access with VISA USB Raw. On top of that you have many device classes. Such as USB COMM, for message based devices much like RS-232. Or USB Mass Storage for mass storage devices, USB HID for human interface devices such as keyboards, mice or similar, USB Test and Measurement which is similar to the Mass Storage class in the used endpoints but specifically adapted to implement also the IEEE 488.2 commands on top of that. And while it's not to difficult to implement USB T&M in a device, provided you know what you do and have created USB devices already, this interface class is only really used by T&M manufacturers and there also only by a few, usually associated with the VXI P&P consortium.
Each device class has specific endpoints it uses to transport data between the two ends, and specific ways to use the interrupt, bulk and control mechanismes that USB Raw provides. While a USB Mass storage implementation of a LabVIEW driver based on USB Raw could be used as underlaying component to implement USB T&M, there is no point in trying to talk with USB T&M commands (your *IDN? command) with a mass storage device, since it's about the same than if you would talk in Mandarin to someone only understanding English.
@kimhyun wrote:
How do we know what to use for request type and request inputs for both control in and control out vis when we are using a pendrive?
By reading and understanding the USB specifications! No that is not a goodnight story for children and needs quite a bit of technical background in order to be comprehensive, but such is life. You can't build a skyscraper only knowing how to put Lego bricks together.
