Install BeagleBone

The xPL protocol is light enough to run on simple machines such as the BeagleBone.

Install Ubuntu

The BeagleBone comes with an Angstrom distribution. Whilst this Linux distribution is tailored for embedded devices, Ubuntu's ARM port is easier to use for people used to Ubuntu.

Different methods allow to install Ubuntu on the BeagleBone. If one intends to use the serial port, an image with debugfs is preferred.

Having Ubuntu running, a few configuration steps might be helpful.

Change root password

sudo su
passwd
apt-get update

Swap space

Create a swap file:

dd if=/dev/zero of=/root/swapfile bs=1M count=1024
chmod 600 /root/swapfile
mkswap /root/swapfile

Enable the swapfile:

swapon /root/swapfile
swapon -s
free -k

To enable at reboot, edit /etc/fstab:

/root/swapfile    swap    swap    defaults    0 0

Ethernet

Check the Ethernet connection:

ifconfig | grep inet
ping google.com

Connect to the BeagleBone via SSH to continue working (on a larger window).

ssh root@192.168.1.165

Change host name:

nano /etc/hosts
  change: "127.0.1.1 ubuntu-armhf" to: "127.0.1.1 beagleBoneHostname"
nano /etc/hostname

Set up a bonjour discovery:

apt-get install avahi-daemon libnss-mdns

Give a static address:

nano /etc/network/interfaces
iface eth0 inet static
  address 192.168.1.14
  gateway 192.168.1.1
  netmask 255.255.255.0
  dns-nameservers 192.168.1.1
/etc/init.d/networking restart

Set-up Apple FileProtocol (AFP) sharing:

apt-get install netatalk
nano /etc/netatalk/AppleVolumes.default

Locales

Install locales (for PERL and others):

cd
apt-get install locales
export LANGUAGE=en_US.UTF-8
export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8
locale-gen en_US.UTF-8
dpkg-reconfigure locales

Then edit .bashrc and add: export LC_ALL=C

Command-line editing

Enable history search and bash tab autocompletion:

nano .bashrc
nano /etc/inputrc
apt-get update && apt-get install bash-completion

Install manuals:

apt-get install man-db

Programming tools

Install compilation tools (make, gcc, …):

apt-get install build-essential

Install Perl documentation reader:

apt-get install perl-doc

Local time

Set local time:

ls -lr /usr/share/zoneinfo/Europe/
rm /etc/localtime
ln -s /usr/share/zoneinfo/Europe/Zurich /etc/localtime

Update time on a daily basis with the help of the script /etc/cron.daily/ntpdate containing:

#!/bin/sh
ntpdate ntp.ubuntu.com

Make the script executable:

chmod 755 /etc/cron.daily/ntpdate

Control user

Create user

Add the control user:

useradd -m -g users -G dialout,audio -s /bin/bash control
passwd control

Audio

Try to play a tone:

su
aplay -l
SOUND_FILES_LOCATION='/home/control/Documents/Controls/Sounds'
ll $SOUND_FILES_LOCATION
aplay $SOUND_FILES_LOCATION/pop.wav

Disable the HDMI audio interface by adding to /boot/uboot/uEnv.txt<code>:

optargs=quiet capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN capemgr.enable_partno=BB-BONE-AUDI-01

echo BB-BONE-AUDI-01 > /sys/devices/bone*/slots

Setup line out sound path:

amixer scontrols
amixer set PCM 127
amixer set Line mute
amixer set 'Line DAC' 0
amixer set 'Line Line2 Bypass' 0
amixer set 'Line PGA Bypass' 0
amixer set Mono mute
amixer set 'Mono DAC' 0
amixer set 'Mono Line2 Bypass' 0
amixer set 'Mono Mixer DACL1' mute
amixer set 'Mono Mixer DACR1' mute
amixer set 'Mono Mixer Line2L Bypass' mute
amixer set 'Mono Mixer Line2R Bypass' mute
amixer set 'Mono Mixer PGAL Bypass' mute
amixer set 'Mono Mixer PGAR Bypass' mute
amixer set 'Mono PGA Bypass' 0
amixer set AGC mute
amixer set De-emphasis mute
amixer set HP unmute
amixer set 'HP DAC' 100
amixer set 'HP Line2 Bypass' 0
amixer set 'HP PGA Bypass' 0
amixer set 'HPCOM' mute
amixer set 'HPCOM DAC' 0
amixer set 'HPCOM Line2 Bypass' 0
amixer set 'HPCOM PGA Bypass' 0
amixer set 'Left HP Mixer DACL1' unmute
amixer set 'Left HP Mixer DACR1' 0
amixer set 'Left HP Mixer Line2L' mute
amixer set 'Left HP Mixer Line2R Bypass' 0
amixer set 'Left HP Mixer PGAL Bypass' unmute
amixer set 'Left HP Mixer PGAR Bypass' 0
amixer set 'Left HPCOM Mixer DACL1' mute
amixer set 'Left HPCOM Mixer DACR1' 0
amixer set 'Left HPCOM Mixer Line2L Bypass' mute
amixer set 'Left HPCOM Mixer Line2R Bypass' 0
amixer set 'Left HPCOM Mixer PGAL Bypass' mute
amixer set 'Left HPCOM Mixer PGAR Bypass' 0
amixer set 'Left Line Mixer DACL1' mute
amixer set 'Left Line Mixer DACR1' 0
amixer set 'Left Line Mixer Line2L Bypass' mute
amixer set 'Left Line Mixer Line2R Bypass' 0
amixer set 'Left Line Mixer PGAL Bypass' mute
amixer set 'Left Line Mixer PGAR Bypass' 0

speaker-test -c 2 -t sine

Checks

CPU usage

Check CPU usage:

ps -eo pcpu,user,args | sort -k 1 -r | head -10
echo && ps -eo pcpu,user,args | grep -v ' 0.0 ' | grep -v '%CPU' | sort -k 1 -r | sed 's/[ ^I]\/.*\/perl//' | sed 's/.pl[ ^I].*/.pl/'

Process priorities

Check process priorities:

ps ax -o nice,pid,user,args | grep -v ' NI ' | sort

The lowest numbers correspond to the highest priorities.

Change the priority level of xPL devices:

ps ax -o nice,pid,user,args | grep -v ' grep ' | grep -i xpl-

USER='control'
NEW_LEVEL=-10
SYSTEM_IFS=$IFS; IFS=$'\n'; 
task_list=(`ps ax -o pid,user,args | grep -v ' grep ' | grep -i '/xpl-'`)
IFS=$SYSTEM_IFS
for item in "${task_list[@]}" ;  do
  task_id=`echo "${item}" | sed "s/$USER.*//"`
# echo $task_id
  renice $NEW_LEVEL -p $task_id >/dev/null
done
ps ax -o nice,pid,user,args | grep -v ' grep ' | grep -i xpl-

Upstart daemons

Check the status of init daemons:

initctl list
initctl list | grep xpl-