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

1  –  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

1.1  –  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

1.2  –  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