hi, Does the USB driver which you get along with Windows2000 DDK, support multiple devices?
My next doubt is regarding USB on Application side. Is there any way of ditinguishing between say 120 USB devices of the same family connected to my system via hubs. Like .... You can distinguish different COM ports like "COM1", "Com2" etc.
Is there any similar way of making out between 120 USB devices??
pls help.
Hi,
as i remember USB endpoints under 255 number set host by initialization.
Cheers
hi, thanks a lot for your help. Neo.
Yes.
Windows assigns each device a unique name based on its location and serial number. Than name is stored in the registry and remains constant between boots. But it is not a particularly friendly name as it contains a GUID and other distinguishing information. This name is also not formatted the same in different versions of Windows. If you're writing the driver for the device, you can generate a friendly name for it.
Look into the Microsoft documentation for the SetupDiXXX() function group. Also you won't be able to do 120 devices because of the number of hubs required.
Not all drivers support multiple devices with identical VID/PID, but many do. I don't know what driver you're referring to.
The application retrieves a handle for each device. If you need to keep track of which device is which even if you move the the devices to other ports or power down, then back up, store a unique serial number in each device's descriptors.
With this many devices, identical or not, you can run into bandwidth limits or scheduling problems (depending on the quantity of data and transfer types).
Jan Axelson
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