Difference between revisions of "BeagleBone Black"

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Find below my experiences with the BeagleBone Black (BBB) revision 3.
 
Find below my experiences with the BeagleBone Black (BBB) revision 3.
  
At [[BBB First Boot]] you can read about the first boot of the BeagleBone Black
+
* At [[BBB First Boot]] you can read about the first boot of the BeagleBone Black
 
+
* Add a [[BBB New User]] on your BBB
Adding a WiFi adapter [[BBB WiFi]]
+
* Getting [[BBB Internet over the USB cable]]
 
+
* Set your [[BBB timezone]] to match your local timezone
Yocto Project will enable you to build your own distribution for the BBB. See [[BBB Yocto Project]] for further details.
+
* I talk about adding a WiFi adapter over at [[BBB WiFi]]
==Enabling the DS18B20 thermometer==
+
* Customising your prompt. Look over at [[BBB Customised prompt]]
 
+
* The [https://yoctoproject.org Yocto Project] will enable you to build your own distribution for the BBB. See [[BBB Yocto Project]] for further details.
The version of Debian that my board was supplied with uses the Flattened Device Tree in order to ease the access to GPIO's and other hardware. This are so for the most modern Linux distributions for the ARM processors. The reason for this is mainly because Linus Thorvalds did not want to include the large amount of device drivers for the ARM processor family in the kernel. Se more about the Flattened Device Tree (FDT) on [http://elinux.org/Device_Tree this] site.
+
* Cross compilations means that you develop software on one type of CPU architecture, e.g. Intel X86_64, for execution on another architecture, e.g. the ARM architecture. Se [[BBB Cross Compiler]] for more.
 
+
* Having developed a program on the laptop it would be nice to be able to execute it on the BBB and debug it. See [[BBB Remote Debugging]] for details about this.
From [http://www.hobrasoft.cz/en/blog/bravenec/beaglebone-black-ds1820 this] site I was inspired to set-up the correct dts file enabling the usage of GPIO pin 2 for the 1Wire interface.
+
* Enabling peripheral devices like the OneWire is relatively easy. See [[BBB and OneWire]] for further details.
 
+
* Thoughts on enabling PWM can be found over at [[BBB Enabling PWM]]
Create a file name DS1820-00A0.dts with this content
+
* Linux software is under constant update. If not the kernel, then other utilities are updated either to improve the existing functionality, to remove bugs or to give even more functionality. Jump to [[BBB New Debian Image]] if you would like to run on a new image.
 
+
* Working on bren for development but debugging the BBB next to you is possible, see [[BBB Reverse SSH Tunnelling]]
<source lang=text>
+
* Over at [[BBB Developing Device Drivers]] there are some words about device driver development.
/dts-v1/;
+
* [[BBB WebSockets]] are relatively easy to implement in a C or C++ program if you are in need of transporting data between the BBB and a web client.
/plugin/;
+
* Over at [[BBB Kernel Modules]] I discuss different aspects of extending the kernel by developing a specific device driver.
 
+
* Real men don't backup! They occasionally cry. The rest of us makes regular backups. Take a look at [[BBB Backup your work]]
/ {
+
* A quite comprehensive C++ Library for the BBB is available over at [http://blacklib.yigityuce.com/index.html BlackLib]
    compatible = "ti,beaglebone", "ti,beaglebone-black";
+
* Using the PRU's? Take a look over at [[BBB PRU]]
    part-number = "DS1820";
+
* Sometimes you don't need the HDMI, so you can [[Switch off the HDMI]] and thereby free a lot of IO pins for other purposes
    version = "00A0";
+
* [[Remote monitoring]] of ethernet traffic using Wireshark
 
+
* Realtime programming in C and Assembler is done in the [[CCS]]
    exclusive-use = "P9.12";
+
 
+
    fragment@0 {
+
        target = <&am33xx_pinmux>;
+
        __overlay__ {
+
            ds1820_pins: pinmux_ds1820_pins {
+
                pinctrl-single,pins =  <0x78 0x37>;
+
            };
+
        };
+
    };
+
 
+
    fragment@1 {
+
        target = <&ocp>;
+
        __overlay__ {
+
            onewire@0 {
+
                status          = "okay";
+
                compatible      = "w1-gpio";
+
                pinctrl-names  = "default";
+
                pinctrl-0      = <&ds1820_pins>;
+
                gpios          = <&gpio2 28 0>;
+
            };
+
        };
+
    };
+
};
+
</source>
+
 
+
Compile the specification into a dtbo binary file
+
 
+
<source lang=bash>
+
dtc -O dtb -o /lib/firmware/DS1820-00A0.dtbo -b 0 -@ DS1820-00A0.dts
+
</source>
+
 
+
Finally in order to enable this part of the device tree perform at every boot this command
+
 
+
<source lang=bash>
+
echo DS1820 > /sys/devices/bone_capemgr.*/slots
+
</source>
+
 
+
The thermometer should now show up in the /sys/bus/w1/devices folder
+
 
+
drwxr-xr-x 2 root root 0 Jan  1  2000 .
+
drwxr-xr-x 4 root root 0 Jan  1  2000 ..
+
lrwxrwxrwx 1 root root 0 Feb 21 10:49 28-000005a7ce64 -> ../../../devices/w1_bus_master1/28-000005a7ce64
+
lrwxrwxrwx 1 root root 0 Feb 21 10:49 w1_bus_master1 -> ../../../devices/w1_bus_master1
+
 
+
the 28-00000nnnnnnn is the thermometer - they are all uniquely identified, so the n's will vary.
+
 
+
=== Test with Python===
+
To check that the thermometer work correct prepare this short test program in a file named test.py where you of course will adjust the thermometer ID to suit your set-up:
+
 
+
<source lang=python>
+
import time
+
 
+
w1="/sys/bus/w1/devices/28-000005a7ce64/w1_slave"
+
 
+
while True:
+
    raw = open(w1, "r").read()
+
    print "Temperature is "+str(float(raw.split("t=")[-1])/1000)+" degrees"
+
    time.sleep(1)
+
</source>
+
 
+
Execute the program
+
 
+
<source lang=bash>
+
python test.py
+
</source>
+
 
+
you should get something similar to this
+
 
+
root@klaus-BBB:~/ds18b20# python test.py
+
Temperature is 24.0 degrees
+
Temperature is 24.0 degrees
+
Temperature is 24.062 degrees
+
Temperature is 24.062 degrees
+
^CTraceback (most recent call last):
+
  File "test.py", line 8, in <module>
+
    time.sleep(1)
+
KeyboardInterrupt
+
root@klaus-BBB:~/ds18b20#
+
 
+
===Test using Bonescript===
+
 
+
This source first locates the attached thermometer and then uses it for temperature reading.
+
 
+
This code is only able to handle one thermometer at a time, or in fact only one 1-wire device at at time.
+
 
+
<source lang=javascript>
+
//
+
// Interface for the thermometer
+
// Author  : Klaus Kolle
+
// Date    : 2015 02 22
+
// Revision : 0.0.3
+
 
+
var b = require('bonescript');
+
var f = require('fs');
+
 
+
//console.log('Hello, Thermostate.');
+
 
+
var temperature;
+
 
+
// Read from the 1-wire thermometer
+
// The 28-00000nnnnnnn will change depending of the device connected
+
//
+
var oneWireDir;
+
 
+
locateThermometer();
+
 
+
function locateThermometer()
+
{
+
  var initialDir = '/sys/bus/w1/devices/';
+
  var regExpr = '28-00000';
+
  var dir = [];
+
  var i;
+
  // Get all files and directories in the dir
+
  var dirs = f.readdirSync(initialDir);
+
  // Did we gat anything - if not the cape manager is probably not initialised
+
  // with the dtbo compiled device tree
+
  if (dirs.length > 0)
+
  {
+
    for (i = 0; i < dirs.length; i++)
+
    {
+
      // Only select the directories matching the pattern
+
      if(dirs[i].match(regExpr))
+
      {
+
        dir.push (dirs[i]);
+
      }
+
    }
+
    // Currently the code only accepts one thermometer
+
    oneWireDir = initialDir + dir + "/w1_slave";
+
  }
+
}
+
 
+
function readTemp()
+
{
+
  // Callback function for the timer
+
  b.readTextFile(oneWireDir, printTemp);
+
}
+
 
+
// The 1-wire returs this when reading the device
+
// klaus@klaus-BBB:~$ cat /sys/bus/w1/devices/28-000005a7ce64/w1_slave
+
// a5 01 4b 46 7f ff 0b 10 f7 : crc=f7 YES
+
// a5 01 4b 46 7f ff 0b 10 f7 t=26312
+
// Therefore a split is needed. We need the string after the second =
+
 
+
function printTemp(x)
+
{
+
  // We receive the data i x
+
  if (x.data != '')
+
  {
+
    var stringToSplit = x.data;
+
    // Split at = - three resulting strings are returned
+
    var arrayOfStrings = stringToSplit.split('=');
+
    // We are only interesd in the last
+
    temperature = (arrayOfStrings[2]) / 1000;
+
    console.log("Temp: " + temperature);
+
  }
+
}
+
 
+
setInterval(readTemp, 5000);
+
</source>
+
 
+
Expect a readout like this
+
 
+
Temp: 24.687
+
Temp: 24.75
+
Temp: 24.75
+
Temp: 24.687
+
Temp: 24.75
+
Temp: 24.75
+
Temp: 24.75
+
Temp: 24.687
+
 
+
==Development on a PC host and remote debugging ==
+
 
+
A few things are needed in order to set-up development of programs, that shall execute on an ARM platform. You'll need a cross compiler - a compiler that can generate ARM executable code while the compiler is executed on the PC platform, which is typically a Intel X86_64 architecture.
+
 
+
===Cross Compiler===
+
 
+
The Fedora package system does not contain a suitable compiler for the ARMv7 processor.
+
 
+
Luckily Linaro, does maintain a toolchain suitable for us. At [http://releases.linaro.org/14.11/components/toolchain/binaries this] point you can find the newest binaries for your operating system. Go up the directory structure to discover if a newer compiler has been released.
+
 
+
The following is suited for [http://releases.linaro.org/14.11/components/toolchain/binaries/arm-linux-gnueabihf Fedora Linux] and other Linux'es as they are rather generic.
+
 
+
<source lang=bash>
+
]$ cd ~/Downloads
+
$] wget http://releases.linaro.org/14.11/components/toolchain/binaries/arm-linux-gnueabihf/gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf.tar.xz
+
</source>
+
 
+
which will download the newest version on the time of writing this.
+
 
+
I keep downloaded tools in the /opt directory rather than in the /usr/local or other places in the /usr tree.
+
 
+
<source lang=bash>
+
]$ cd /opt
+
]$ mkdir toolchains
+
]$ cd toolchains
+
]$ tar Jxvf ~/Downloads/gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf.tar.xz
+
]$ ln -s gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf/ gnueabihf
+
]$ file gnueabihf/bin/arm-linux-gnueabihf-gcc
+
</source>
+
 
+
These commands will create a toolchains directory in /opt and unpack the downloaded binaries into a structure. A symbolic link '''gnueabihf''' is created. This link can later be changed if a newer version of the compiler and libraries are downloaded.
+
 
+
The last command is just for ensuring that you've got the correct package downloaded. Expect something like this:
+
 
+
[klaus@klaus-x230 bin]$ file arm-linux-gnueabihf-gcc
+
arm-linux-gnueabihf-gcc: '''ELF 64-bit LSB executable, x86-64''', version 1 (SYSV), dynamically linked, interpreter
+
/lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=71722376ff3af9eee5caf7bdfa2ecc350db0a590, not stripped
+
[klaus@klaus-x230 bin]$
+
 
+
===Develop a Cross Compiled Program===
+
 
+
Start Eclipse and create a new project:
+
 
+
[[File:RemoteDebugging.png | 400px]]
+
 
+
'''''Notice the settings for the Cross GCC'''''
+
 
+
On one of the next dialogues you have to specify what the prefix for the cross compiler tools are and where they resides.
+
 
+
[[File:RemoteDebugging1.png | 400px]]
+
 
+
In the project create a new C source file and fill in some "Hello World" stuff.
+
 
+
Save and compile (Ctrl+S, Ctrl+B).
+
 
+
In a console go to <path to your project>/Debug
+
 
+
<source lang=bash>
+
]$ file <your binary (project name)>
+
</source>
+
 
+
Expect something like this:
+
 
+
[klaus@klaus-x230 Debug]$ file TestRemoteDBG
+
TestRemoteDBG: '''ELF 32-bit LSB executable, ARM,''' EABI5 version 1 (SYSV), dynamically linked,
+
interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 2.6.16, BuildID[sha1]=e8baff7637d637533f3730021407ffdc6d4c314e, not stripped
+
[klaus@klaus-x230 Debug]$
+
 
+
This tells us that the compiler has produced ARM executable code.
+
 
+
===Remote Debugging===
+
 
+
In order to be able to debug remote the remote board needs a suitable '''gdbserver'''. There is one already onboard - or it can be downloaded using apt-get, but that one does not operate correct with the toolchain downloaded previously.
+
 
+
But luckily there is a suitable gdbserver included with the gnueabihf tools.
+
 
+
<source lang=bash>
+
]$ scp /opt/gnueabihf/bin/gdbserver <username>@<your BBB IP>:~/
+
</source>
+
 
+
If you set-up password-less login over SSH (see [http://klaus.ede.hih.au.dk/index.php/Linux_hints#Copy_your_credentials_to_a_remote_host this] page for details) your life will be much easier.
+
 
+
You can test your newly developed ARM program on your BBB.
+
 
+
<source lang=bash>
+
]$ scp <path to your project>/Debug/<yourbinary> <username>@<Your BBB IP address>:~
+
</source>
+
 
+
Log on to your BBB and try
+
 
+
<source lang=bash>
+
]$ ./<yourbinary>
+
</source>
+
 
+
and inspect the output.
+
 
+
Next thing is to set up remote debugging.
+
 
+
In Eclipse select the '''Run''' menu and select '''Debug Configurations'''
+
 
+
[[File:RemoteDebugging2.png | 500px]]
+
 
+
First mark the C/C++ Remote debugging and then click on the new button to the upper left corner of the dialogue.
+
 
+
You'll get a dialogue like this:
+
 
+
[[File:RemoteDebugging3.png|500px]]
+
 
+
Press the '''New''' button to the right of the ''Connection'' line.
+
 
+
This will open a dialogue for setting up the connection to the BBB. We'll use SSH.
+
 
+
[[File:RemoteDebugging4.png | 500px]]
+
 
+
You can use the local IP address or any other configured for the BBB.
+
 
+
[[File:RemoteDebugging5.png | 500px]]
+
 
+
Returning to the main Debug Configuration dialogue you'll see that the Connection now has been filled in with the details you just provided.
+
 
+
[[File:RemoteDebugging6.png | 500px]]
+
 
+
Next you'll have to specify the complete path of your program to execute on the BBB. The program will be sent over the SSH connection before launching the gdbserver - so any changes made on the development host will be reflected on the binary on the BBB.
+
 
+
Here I just placed the binary in my home directory, but it could be anywhere suitable.
+
 
+
[[File:RemoteDebugging7.png | 500px]]
+
 
+
Next thing to do is to click on the Debugger tab in the top of the dialogue. In this part of the settings you'll have to specify a complete path and name of the debugger - in this case we'll use the Linaro supplied residing in /opt/toolchains/gnueabihf
+
 
+
[[File:RemoteDebugging8.png | 500px]]
+
 
+
Also click on the '''Shared libraries''' tab and click '''Add''' and navigate to /opt/toolchains/gnueabihf/libc/lib and add that. This will remove some error messages during debugging.
+
 
+
[[File:RemoteDebugging16.png | 500px]]
+
 
+
Adjust the path to the gdbserver on the BBB.
+
 
+
[[File:RemoteDebugging15.png | 500 px]]
+
 
+
You are now ready to debug. Press the '''Debug''' button.
+
 
+
[[File:RemoteDebugging9.png | 500px]]
+
 
+
You're asked a password for your login on the BBB.
+
 
+
[[File:RemoteDebugging10.png | 500px]]
+
 
+
And the you're told what system you're debugging.
+
 
+
[[File:RemoteDebugging11.png | 500px]]
+
 
+
And finally the debugger launches the program that has been transfered to the remote BBB and the gdbserver is launched with the program a a parameter and you can debug you application just like any other application.
+
 
+
This set-up has been heavily inspired by [http://linuxembeded.blogspot.dk/ this site] and the video by D. Molloy at [https://www.youtube.com/watch?annotation_id=annotation_4233682927&feature=iv&src_vid=vFv_-ykLppo&v=hzZHcH5quow YouTube].
+
 
+
==Installing a new official Debian image on a SD card==
+
Download from the [http://beagleboard.org/latest-images BeagleBoard.org] site or elsewhere a fresh image suitable for the BBB.
+
 
+
You will typically get a file named like this
+
bone-debian-7.8-lxde-4gb-armhf-2015-03-01-4gb.img.xz
+
Date and version number may vary.
+
 
+
In your download directory execute this command
+
<source lang=bash>
+
]$ xz -dk bone-debian-7.8-lxde-4gb-armhf-2015-03-01-4gb.img.xz
+
</source>
+
 
+
this will unpack the image into a file like this
+
bone-debian-7.8-lxde-4gb-armhf-2015-03-01-4gb.img
+
 
+
===Locate your SD card===
+
Have a 4GB SD ready and inserted into your computer. Execute
+
<source lang=bash>
+
]$ ll /dev/sd*
+
</source>
+
or
+
<source lang=bash>
+
]$ ll /dev/mmcblk*
+
</source>
+
the way your computer interface to the SD card will either see it as a disk drive and name it '''/dev/sd''N'',''' where '''''N''''' is the next free letter - e.g. you have one disk already installed in your computer it is most likely sda[09], the next disk the system recognises will be sdb.
+
 
+
On my laptop when I use the SD slot directly in the laptop the system sees the SD card as a new mmc block device, hence the '''mmcblk''' name.
+
 
+
Another way to determine the name of the freshly inserted SD card is to execute
+
<source lang=bash>
+
]$ ls -lart /dev
+
</source>
+
this will list the content of '''/dev''' in reverse order with the newest at the end of the list, i.e. at the bottom of your console.
+
 
+
Removing the SD card and rerunning the command will give you the final evidence to what the name is, since it is now missing in the list.
+
 
+
If the SD card i preformatted, which most are, you will see two - or more - devices like this
+
 
+
<source lang=bash>
+
]$ ll /dev/mmcblk*
+
brw-rw----. 1 root disk 179, 0 May  1 13:15 /dev/mmcblk0
+
brw-rw----. 1 root disk 179, 1 May  1 13:15 /dev/mmcblk0p1
+
]$
+
</source>
+
 
+
The '''mmcblk0''' is the main block device and the '''mmcblk0p1''' is the first partition on the disk.
+
 
+
===Transferring the image to the SD card===
+
 
+
In order to transfer the disk image to the SD card first ensure that it is not mounted, e.g. by removing the card and re-insert it into the reader slot or by running a '''umount''' command (RTFM umount).
+
 
+
Next issue this command
+
<source lang=bash>
+
]$ sudo dd if=bone-debian-7.8-lxde-4gb-armhf-2015-03-01-4gb.img of=/dev/mmcblk0 bs=1M
+
</source>
+
The '''dd''' command is a versatile utility that takes an input file ('''if''') and an output file ('''of''') and copies the input file to the output file ('''/dev/mmcblk0''') in 1 mega bytes blocks ('''BS=1M'''). Expect 10 to 20 minutes before the command returns depending on the speed of your card reader and the SD card. Note here, that we use the main block interface file '''mmcblk0''' not the ''mmcblk0p1'' or the '''sdb''' not the ''sdb1''.
+
 
+
When finished you will get a report like this
+
3700+0 records in
+
3700+0 records out
+
3879731200 bytes (3.9 GB) copied, 557.971 s, 7.0 MB/s
+
and your SD is ready to run in the BBB.
+
 
+
===Starting the new image on BBB===
+
Remove the SD card from your computer and insert it into the BBB.
+
 
+
Find the user button located just above the SD card slot.
+
 
+
Press and hold the button while applying power to the device. When the device starts to boot (blinking leds) release the user button.
+
 
+
If you have previously connected your BBB using the
+
<source lang=bash>
+
]$ ssh root@192.168.7.2
+
</source>
+
you will probably get a message like this
+
]$ ssh root@192.168.7.2
+
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!    @
+
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
+
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
+
It is also possible that a host key has just been changed.
+
The fingerprint for the ECDSA key sent by the remote host is
+
80:98:39:60:af:8e:db:14:47:9f:76:6a:88:89:12:e3.
+
Please contact your system administrator.
+
Add correct host key in /home/klaus/.ssh/known_hosts to get rid of this message.
+
Offending RSA key in /home/klaus/.ssh/known_hosts:49
+
ECDSA host key for 192.168.7.2 has changed and you have requested strict checking.
+
Host key verification failed.
+
which tells us that in the ~/.ssh/known_hosts file we keep a fingerprint of hosts that we have previously accepted to be legal computers to connect to. You have to edit the ~/.ssh/known_hosts file and remode the line(s) beginning with 192.168.7.2 and then try to connect once again.
+
 
+
First time you connect to your new image you will be prompted to verify the fingerprint of the connecion. Do that by typing yes.
+
 
+
Determine the version of your new image by issuing this command
+
<source lang=bash>
+
root@beaglebone:~# uname -a
+
Linux beaglebone 3.8.13-bone70 #1 SMP Fri Jan 23 02:15:42 UTC 2015 armv7l GNU/Linux
+
root@beaglebone:~#
+
</source>
+
 
+
This is at the time of wirting the latest official supported image, but not necessarily the newest - you may find newer images floating around the Internet. The following device driver development will take outspring in the version.
+
 
+
=Developing a device driver for the BBB=
+
 
+
This section is heavily inspired by [http://derekmolloy.ie/writing-a-linux-kernel-module-part-1-introduction/ Derek Molloy's] fine writing about device driver development.
+

Revision as of 15:01, 16 February 2018

Find below my experiences with the BeagleBone Black (BBB) revision 3.

  • At BBB First Boot you can read about the first boot of the BeagleBone Black
  • Add a BBB New User on your BBB
  • Getting BBB Internet over the USB cable
  • Set your BBB timezone to match your local timezone
  • I talk about adding a WiFi adapter over at BBB WiFi
  • Customising your prompt. Look over at BBB Customised prompt
  • The Yocto Project will enable you to build your own distribution for the BBB. See BBB Yocto Project for further details.
  • Cross compilations means that you develop software on one type of CPU architecture, e.g. Intel X86_64, for execution on another architecture, e.g. the ARM architecture. Se BBB Cross Compiler for more.
  • Having developed a program on the laptop it would be nice to be able to execute it on the BBB and debug it. See BBB Remote Debugging for details about this.
  • Enabling peripheral devices like the OneWire is relatively easy. See BBB and OneWire for further details.
  • Thoughts on enabling PWM can be found over at BBB Enabling PWM
  • Linux software is under constant update. If not the kernel, then other utilities are updated either to improve the existing functionality, to remove bugs or to give even more functionality. Jump to BBB New Debian Image if you would like to run on a new image.
  • Working on bren for development but debugging the BBB next to you is possible, see BBB Reverse SSH Tunnelling
  • Over at BBB Developing Device Drivers there are some words about device driver development.
  • BBB WebSockets are relatively easy to implement in a C or C++ program if you are in need of transporting data between the BBB and a web client.
  • Over at BBB Kernel Modules I discuss different aspects of extending the kernel by developing a specific device driver.
  • Real men don't backup! They occasionally cry. The rest of us makes regular backups. Take a look at BBB Backup your work
  • A quite comprehensive C++ Library for the BBB is available over at BlackLib
  • Using the PRU's? Take a look over at BBB PRU
  • Sometimes you don't need the HDMI, so you can Switch off the HDMI and thereby free a lot of IO pins for other purposes
  • Remote monitoring of ethernet traffic using Wireshark
  • Realtime programming in C and Assembler is done in the CCS