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UDP Example

QP-lwIP

The example application opens a UDP connection at the port 777. Any UDP packets sent to that connection are interpreted as text to display on the LCD. The application responds back to the sender with a UDP packet that contains the original text plus the prepened sequence number. Obviously, the simple text format is used for simplicity. In real-life applications binary format could be more efficient.

Application Note (1.4MB PDF)

To facilitate testing of UDP connectivity, a simple console application called qudp for Windows or Linux hosts is provided in the QP-lwIP example code. The following listing shows an example output generated from the qudp applicaiton: 

C:\software\qpcpp\tools\qudp\win32\vc6>Debug\qudp 192.168.0.100
qudp utility (c) Quantum Leaps, LLC, www.state-machine.com
Opening and binding local socket at port=1777...ready
Remote UDP connection: IP-address=192.168.0.100, port=777
Type command(s); press Enter to send command, ESC to quit
Hello
Sending:  "Hello"
Received: "Hello-1"
How are
Sending:  "How are"
Received: "How are-2"
you?
Sending:  "you?"
Received: "you?-3"
Done.

Please refer to the Quantum Leaps Application Note: "QP and lwIP TCP/IP Stack" for more information. The Application Note in PDF is provided in the QP-lwIP example code.