1 SET
  Used to set the USB SDA extension environment.

2 CONTROLLER
  Set the controller to be examined.  The default controller is always
  OHA0 even if the system does not have an Open Host Controller Interface
  controller.

  Format
     USB SET CONROLLER OHB0:

3 Parameter

device-name:

   The name of the device whose characteristics are to be added. The
   device name has the form ddcu

   where:

   dd    is the device code - for example, OH (The driver name
         corresponds to the device code; in this case, the driver
         name would be SYS$OHCIDRIVER.  Supported devices are OH,
          EH, and UH.

   c     is the controller designation A through Z;

   u     is the unit number for USB controllers, which is always 0.

   OpenVMS device names consist of the two-character device
   code, followed by the controller designation, the unit number
   (which can be 1 to 4 characters), and a colon (:).

2 UHCI 
  Used to set UHCI driver behavior.  Presently the only supported item is
  diagnostic tracing.

3 TRACE
  Enable event tracing using the tracing capability in SDA.  You must load
  and start tracing in order for this command to become effective.

  Format

     USB SET UHCI TRACE parameter

4 Parameter

event-mask:

  This hex number is a mask of all the events to be enabled.  The 
  following events are defined.

        0x1       - Trace Control request start
        0x2 	  - Trace Interrupt start
        0x4	  - Bulk request start
        0x8 	  - Queue request on controller
        0x10	  - Set toggles 
        0x20	  - Complete TD's
        0x40 	  - All controller interrupts
        0x80 	  - Normal completion
        0x100 	  - Error interrupts
        0x200 	  - Bit stuffing error
        0x400	  - CRC error
        0x800	  - Timeout errors
        0x1000	  - Babble errors
        0x2000	  - Data unerrun/overrrun 
        0x4000    - Stall events
        0x8000	  - Poller timer tick all events
        0x10000   - Port 1 timer tick data
        0x20000	  - Port 1 changes reported to hubdriver
        0x40000	  - Port 2 timer tick data
        0x80000   - Port 2 changes reported to hubdriver
        0x100000  - Port reset start
        0x200000  - Port reset timeout
        0x400000  - Port reset wait for CSC
        

4 Example
  This example shows enabling tracing for queueing control request
  to the UHA0 controller.

SDA> usb set con uha
Controller set to UHA
SDA> usb set uhci trace 1
Tracing code not enabled