Shows a Physical Transmit Descriptor.  A transmission can consist
   of several Physical Transmit Descriptors.

   Format
      USB SHOW UHCI PHYTD [address]

1  –  Example

 SDA> USB SHO UHCI PHYTD 89fe02c0
 Physical Transfer Descriptor
 ----------------------------------  ----------------
 Forward link                                89732134
 Backward lnik                               89732134
 Size                                           0020
 Type                                             8b
 sub type                                         fd
 Physical address of this TD                 001c22d0
 Physical part of TD
 Link Pointer                                00000001
    Terminate set
    Transmit Descriptor
    Phys Address                             00000000
 Control and Status Field                    05000007
    Transfer length                          00000007
    Transfer status                          00000000
    Interrupt on complete 1 <on>                    1
    Isocronous TD if set                            0
    Low Speed device if set                         1
    Error count                                     0
    Short Packet Detect 1 allow short packet        0
 Token field                                 00e88269
    Packet ID                                      69
    Device_address                                 02
    Endpoint address                               01
    Data Toggle                                     1
    Max XFER Length                              0007
 Data Buffer Physical Address                09756410
 SDA>