Instructions for using lnpd
First, you need to untar the package, with
tar xfvz lnpd.tgz. Follow the instructions in the README
file for compiling. Then, I had to add the following line to my
.cshrc file:
setenv LD_LIBRARY_PATH
/home/studentxx/lnpd/lnpd+liblnp/liblnp:$LD_LIBRARY_PATH
or to the .bashrc file:
export LD_LIBRARY_PATH=/home/studentxx/lnpd/lnpd+liblnp/liblnp:$LD_LIBRARY_PATH
where I assume that /home/studentxx is the path to the
directory where you have expanded lnpd.tgz.
To run it, get two windows. On one, do, from the
lnpd/lnpd+liblnp/lnpd directory:
./lnpd --nolock --debug --log=/dev/stdout --verbosity=i
From the other one, go to the lnpd/lnpd+liblnp/applications
directory, and do:
./lucatest
This will list on the screen the packets it is receiving. Each packet
is listed in two lines: the first line contains the hex dump, and the
second line is the packet content.
I tested this code, and I believe it is free of bugs.
Suggestions
You have to shut off both lnpd and lucatest before
loading new programs onto the Lego brick, otherwise strange things may
happen (the Lego goes into a funny state and stops working).
Also, you need to start a fresh instance of lnpd and
lucatest from time to time.
Finally, as you can see from the documentation for lnpd,
there may be a way to write all of your code for the PC, and debug it
there first, and only later port it to the Lego brick.
Once you get lnpd running, the Lego side and the PC side look
the same to a running application.
A final note
Depending on the system, it might be the case that you can run
lnpd (the first of the two windows above) only as root.
Otherwise, the PC was not receiving any packets, essentially.
I don't have this problem on my PCs, but if you have it in the lab,
let me know.
Let me know if there are any problems.
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