CSCI E-92: Application Note 15

Connecting a terminal emulator to UART2
---------------------------------------

UART2 is an emulated serial port that that is available either over
(1) the USB cable connected to the J13 connector on the TWR-K70F120M
board or (2) on the DB9 connector on the TWR-SER board.  To use the
DB9 connector on the TWR-SER board, a serial to USB adapter such as
the Tripp-Lite Keyspan USA-19HS High-Speed USB to Serial Adapter is
required.

In CSCI E-92, initially we are using just UART5 that is available
using the Adafruit 954 USB to TTL Serial Cable adapter connected to
the J6 header on the TWR-K70F120M board.

Please read this application note to use UART2 in addition to UART5
later in the course.


If your UART2 serial input to the K70 is *not* working correctly, this
note should explain how to correct the problem.  If your UART2 serial
input to the K70 *is* working correctly, you should *not* follow the
directions below.


In some cases (depending on whether your computer is running Windows
under a VM, which drivers are installed in Windows, which version of
Windows you are running, and which firmware has been loaded from P&E
Micro), input to UART2 on the K70 from the DE9 socket on the TWR-SER
board may not work properly.  New device drivers from Freescale/P&E
Micro are establishing a connection for UART2 over the usual USB cable
(the one that we are using to power the Tower, load code into the K70,
allow debugging, and transmit the debug console data) rather than over
the DE9 connector on the TWR-SER board.

If you look at:

  Control Panel -> Device Manager -> Ports (COM & LPT) ->
    OSBDM/OSJTAG - CDC Serial Port (http://www.pemicro.com/osbdm,
    http://www.pemicro.com/opensda) (COMx)

this is the COM port that is connected to UART2 over USB.  WIthout
even connecting your serial/USB adapter, try connecting to this COM
port with the correct baud rate, stop bits, etc.  All should work
fine.

-----

For more information on how it is possible for the UART2 I/O lines to
be converted to a signal that is carried over our standard USB
connector, see the "On Board OSBDMSerial Bridge" section of the K70
schematic.  It uses an HCS08 microcontroller (the MC9S08JM60CLD chip)
to support the USB interface and all of the facilities that run over
the USB cable.