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is it allowed to have a USB composite device with 2 MSC interfaces?

Tamir Michael

Hello,

Is this supported? from the usbcfg.h file, it seems that this is not supported as one can only indicate the number of one MSC interface. what I want is simple: a device that will map itself to two distinct windows drives. is that allow/supported?

  • 0

    this is dangerous to have of course in terms of file system access rights (is that the reason I don't get it to work?)

  • 0 in reply to Tamir Michael

    You may have two (or more) MSC interfaces on single device.
    But it means you have to duplicate everything on the source code for the multiple MSC interfaces - descriptors, request and endpoint handlers.

    Instead, you may declare two (or more) logical units (drives) under single MSC interfaces - just like attaching two hard disks under ATA.

    For two drives, return 1 for Get_Max_Lun request.
    And then, the host specifies the LUN (Logical Unit Number) for CBW and SCSI commands, to access one of the drives.

    Tsuneo