== Mote-PC Serial Communication ==

The basic abstraction for mote-PC communication is a '' packet source ''. A packet source is a communication medium over which an application can receive packets from and send packets to a mote. 
Examples of packet sources include serial ports, TCP sockets, and the SerialForwarder tool. Most TinyOS communication tools take an optional -comm parameter, which allows you to specify the packet source as a string. For example: 

{{{

node1-2:~# java net.tinyos.tools.Listen -comm serial@/dev/ttyUSB0:telosb

}}}

tells Listen tool to use the serial port /dev/ttyUSB0 at the correct speed for a telosb mote.

Listen creates a packet source and just prints out every packet it sees. Output should look something like this:
{{{
 
node1-2:/opt/tinyos-2.1.0/apps/BaseStation# java net.tinyos.tools.Listen -comm serial@/dev/ttyUSB0:telosb
serial@/dev/ttyUSB0:115200: resynchronising
00 FF FF 00 01 04 00 06 00 01 00 4E 
00 FF FF 00 01 04 00 06 00 01 00 4F 
00 FF FF 00 01 04 00 06 00 01 00 50 
00 FF FF 00 01 04 00 06 00 01 00 51 
00 FF FF 00 01 04 00 06 00 01 00 52 
00 FF FF 00 01 04 00 06 00 01 00 53 
00 FF FF 00 01 04 00 06 00 01 00 54 
00 FF FF 00 01 04 00 06 00 01 00 55 
00 FF FF 00 01 04 00 06 00 01 00 56 
00 FF FF 00 01 04 00 06 00 01 00 57 
00 FF FF 00 01 04 00 06 00 01 00 58 
00 FF FF 00 01 04 00 06 00 01 00 59 
00 FF FF 00 01 04 00 06 00 01 00 5A 
00 FF FF 00 01 04 00 06 00 01 00 5B 

}}}


We use MsgReader to print out the messages. 

{{{

node1-2:~# java net.tinyos.tools.MsgReader -comm serial@/dev/ttyUSB0:telosb BlinkToRadioMsg

}}}

MsgReader reads the packet send to the serial port, looks at its AM type, and if it matches the AM type of one of the Java message classes passed at the command line, it prints out the packet. We see the output like this:

{{{

1152232617609: Message
  [nodeid=0x2]
  [counter=0x1049]

1152232617609: Message
  [nodeid=0x2]
  [counter=0x104a]

1152232617609: Message
  [nodeid=0x2]
  [counter=0x104b]

1152232617621: Message
  [nodeid=0x2]
  [counter=0x104c]

}}}