© 2000 Ubicom, Inc. All rights reserved. - 21 - www.ubicom.com SX IrDA Virtual Peripheral Implementation AN16 4.0 Sample Applications Using the Virtual Peripheral The IrDA Virtual Peripheral can be used in two different
scenarios:  for  communication  with  another  SX  running
the Virtual Peripheral or with a Windows 95 computer (or
similar) with an IrDA port. The next two sections describe
three  demonstrations  of  the  Virtual  Peripheral  in  these
two scenarios.
Note:Since the Virtual Peripheral complies with the IrDA
standard it will communicate with any other IrDA compli-
ant device (such as a 3Com PalmPilot or digital camera).
For this to be useful, the other device would also need to
support IrComm (there are many high protocols at the top
level  of  the  IrDA  stack  and  all  are  optional)  or  the  SX
would need to support the particular protocol used by the
device. 4. 1 SX TO WINDOWS COMMUNICATION (IRCOMM) 4.1.1   Transparent IrComm Application Description The  ‘Transparent  IrComm’  sample  application  connects
the Debug UART port to the IrComm virtual COM port of
a PC using the IrDA IrComm reliable connection based
protocol. Once a connection has been established by the
PC any characters sent down the PC’s virtual com port
will appear out the SX Debug port and vice-versa.
The  application  does  not  buffer  the  data  and  does  not
send the valid/error messages out the debug port. In the
rare case that an error occurs both the corrupt data and
the valid data will be displayed. All frame errors, transmit
not-acknowledges,  and  receive  frame  numbering  errors
will still be shown on the ‘ERR’ LED.
The application cannot transmit data until it has control of
the  IR  link  and  so  any  characters  received  down  the
debug  port  for  transmission  must  be  stored  until  trans-
mission   is   possible.   To   achieve   this   the   application
includes an 8-byte buffer for data pending transmission. 4.1.2   SX to PC IrComm Application Description The ‘SX to PC IrComm’ sample application will respond
to user commands entered into a terminal window con-
nected to the virtual IrComm port of the PC. The SX will
respond as follows:
•    ‘?’ will return the text string ‘SX IrComm Terminal’ to the       user.
•    ‘c’ will return the value of port c (raw byte) to the user.
•    ‘r’ will return the 128 byte general register file (raw       bytes) to the user.
The  application  is  completely  reliable  in  that  it  will  cor-
rectly discard invalid received data and will correctly re-
send any transmitted data as requested. 4.1.3   IrComm requirements •    MS Windows 95/98 machine.
•    Infrared IrDA port.
•    Infrared drivers installed (The Windows 95 IrDA driver can be found at www.microsoft.com/windows/95downloads/). •    A serial connection to the SX if debug is of interest (The       serial cable should be a straight-through cable with at
      least TX, RX, and GND connections.
•    Windows terminal software capable of connecting to       the IrDA virtual com port.
Note:Windows  95  HyperTerminal  can  only  connect  to
COM1-4 and if the PC has a physical COM4 then the vir-
tual com port will be higher. 4.1.4   IrComm Operation •    Double-click on the “Infrared” icon in control panel to       show the Infrared window.
•    Under ‘Options’ ensure that ‘Search for devices in       range” is selected (typically every 3 seconds).
•    Under ‘Options’ note the ‘Providing application support’       virtual LPT and COM port numbers.
•    Open a terminal program for the debug on the appro-       priate COM port at 115200,n,8,1, no handshaking.
•    Power up the SX. Power is indicated by the ‘PWR’       LED.
•    The Infrared monitor should indicate that there is a de-       vice in range called ‘SX IrComm Device’
•    The IR RX indication LED should be indicating received       data about every 3 seconds. The IR TX indication LED
      should flash at a random interval into the RX phase in-
      dicating a reply in a random slot number.
•    Open another terminal program for the IrDA virtual com       port. Use the ‘application support’ COM port number
      noted from the Infrared monitor with any parameters
      (they are irrelevant). Note that Windows does not make
      these virtual ports available to a DOS window.
•    The Infrared monitor should say ‘Communicating with       – Name: SX IrComm Device, Description: SX IrDA Ir-
      Comm Demonstration’, ‘Good at 115.2 kbps’.
•    If the ‘ShowConnect’ debug is enabled in the SX code       then the debug window will show a ‘[‘when the connec-
      tion has been established and a ‘]’ when the connection
      has been terminated or lost.
•    If the ‘Transparent IrComm’ application code is being       used on the SX then anything entered into the virtual
      COM port terminal window will appear in the debug ter-
      minal window and vice-versa.
•    If the ‘SX 2 PC IrComm’ application code is being used       on the SX then the SX will respond to a ‘?’ (in the virtual
      COM port terminal window) by returning the text string
      ‘SX IrComm Terminal’, a ‘c’ by returning the value of
      port c, and to a ‘r’ by returning the 128 byte register
      dump.
•    Connection will be maintained until the virtual COM       port is closed or the devices cannot see each other for
      more than 3 seconds.
•    Another interesting test is to install a printer driver in windows connected to the virtual LPT port. With the
‘Transparent IrComm’ application, all the graphical
printer data will be sent out the debug port of the SX.