How to identify your USB Debug Port's physical connector


Your PC probably will not have a label showing which USB outlet to use
when you are ready to attach the NET20DC Hi-Speed USB 2.0 Debug Cable,
but you can use our software to discover this information quickly when
you have 'root' privileges.  Here's how:

Compile and install our 'ajay.c' kernel module on your Linux platform.
Our 'mmake.cpp' application automates the compilation-step,

			$ ./mmake ajay 

and then with 'root' privleges you can install the resulting 'ajay.ko'
kernel-object into your running kernel:

	  	    # /sbin/insmod ajay.ko

A confirmation-message will be written to your kernel log-file, which 
can be viewed by using the 'dmesg' command:

			  $ dmesg

Installing this module will create a pseudo-file (named '/proc/ajay') 
which you can view using the standard UNIX 'cat' command:

		     $ cat /proc/ajay

Here is what the pseudo-file's output will look like:


                -- USB Enhanced Host Controller registers -- 

  CAPLENGTH=20  HCIVERSION=0100  HCSPARAMS=00104208  HCCPARAMS=00006871 
  CTRLDSSEGM=00000000  PERIODICLISTBASE=3DD5D000 ASYNCLISTBASE=3DC2D000 
  USB2CMD=00010001  USB2STS=00002008  USB2INTR=00000037  FRINDEX=0x1EF7 

  CONFIGFLAG=1 
  PORT0SC=00001005  owner=0  power=1  suspend=0  enabled=1  connected=1 
  PORT1SC=00001000  owner=0  power=1  suspend=0  enabled=0  connected=0 
  PORT2SC=00001000  owner=0  power=1  suspend=0  enabled=0  connected=0 
  PORT3SC=00001000  owner=0  power=1  suspend=0  enabled=0  connected=0 
  PORT4SC=00001085  owner=0  power=1  suspend=1  enabled=1  connected=1 
  PORT5SC=00001000  owner=0  power=1  suspend=0  enabled=0  connected=0 
  PORT6SC=00001000  owner=0  power=1  suspend=0  enabled=0  connected=0 
  PORT7SC=00001000  owner=0  power=1  suspend=0  enabled=0  connected=0 

 DEBUG PORT REGISTERS 
 CNTL_STS=00000000  USBPID=5A0000  DATABUF=00000000-00000000  CONFIG=7F01 


This display shows you which USB ports are currently attached to Hi-Speed
peripheral devices, such as your 'NET20DB' cable, and this output will be
different when you unplug a Hi-Speed USB peripheral device -- or when you 
plug in your device to a different external USB physical connector. 

Our 'dynaview.cpp' application can be used, instead of the 'cat' command,
to show a continuously updated view of the Enhanced USB Host Controller's
registers.  You'll be able to watch the values of the 'connected=' fields 
change, from 0 to 1, or from 1 to 0, as you plug in your USB Debug Cable,
or unplug it, to the different external USB connectors on your system, so
you'll be able to discover which connector is associated with the topmost
port-status displayed (the one labeled 'PORT0SC').  That's the one -- the
only one -- which works with your system's primary EHCI controller using
the 'ajay.c' software-driver we have provided.  

This approach, obviously, is Linux-specific and so you would need to use
another scheme if your PC is running a different operating system.  Some
recent distributions of Linux will direct kernel-messages to the console
as well as the kernel log-file, which interferes with 'dynaview' output,
unless you are running 'dynaview' in a window on your graphical desktop,
but with 'root' privileges you can alter that default behavior using the
standard UNIX 'echo' command with output-redirection, as follows:

		# echo 1 > /proc/sys/kernel/printk

Allan Cruse
06 FEB 2010