Difference between revisions of "Raspberry Pi"
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{{Note|Support for the ARM architecture is provided on http://archlinuxarm.org/ }} | {{Note|Support for the ARM architecture is provided on http://archlinuxarm.org/ }} | ||
− | Posts to the official Arch Linux Forum related to ARM specific issues will be promptly closed. | + | {{Note|Posts to the official Arch Linux Forum related to ARM specific issues will be promptly closed.}} |
== Installing Arch Linux ARM == | == Installing Arch Linux ARM == |
Revision as of 21:47, 7 April 2013
Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki - This article is not meant to be an exhaustive setup guide and assumes that the reader has setup an Arch system before. Arch newbies are encouraged to read the Beginners'_Guide if unsure how to preform standard tasks such as creating users, managing the system, etc. RPi Config - Excellent source of info relating to under-the-hood tweaks. Template:Article summary end
Contents
Article Preface
Installing Arch Linux ARM
See the archlinuxarm documentation.
Audio
Install the needed packages:
pacman -S alsa-utils alsa-firmware alsa-lib alsa-plugins
Optionally adjust the default volume using `alsamixer` and ensure that the sole source "PCM" is not muted (denoted by double MM if muted).
Select an audio source for output:
amixer cset numid=3 x
Where 'x' corresponds to:
- 0 for Auto
- 1 for Headphones
- 3 for HDMI
Caveats for HDMI Audio
Some applications require a setting in /boot/config.txt
to force audio over HDMI:
hdmi_drive=2
Onboard Hardware Sensors
Temperature
Temperatures sensors for the board itself are including as part of the raspberrypi-firmware-tools package. the RPi offers a sensor of the BCM2835 SoC (CPU/GPU):
/opt/vc/bin/vcgencmd measure_temp temp=49.8'C
Alternatively, simply read from the filesystem:
% cat /sys/class/thermal/thermal_zone0/temp 49768
Voltage
Four different voltages can be monitored via /opt/vc/bin/vcgencmd
as well:
% /opt/vc/bin/vcgencmd measure_volts <id>
- core for core voltage
- sdram_c for sdram Core voltage
- sdram_i for sdram I/O voltage
- sdram_p for sdram PHY voltage
Overclocking/Underclocking
The Raspberry Pi can be overclocked by editing /boot/config.txt
, for example:
arm_freq=800 arm_freq_min=100 core_freq=300 core_freq_min=75 sdram_freq=400 over_voltage=0
The optional xxx_min lines define the min usage of their respective settings. When the system is not under load, the values will drop down to those specified. Consult the [Overclocking] article on elinux for additional options and examples.
A reboot is needed for new settings to take effect.
Users may query the current frequency of the CPU via this command:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
Serial Console
Edit the default /boot/cmdline.txt
Change loglevel to 5 to see boot messages
loglevel=5
Change speed from 115200 to 38400
console=ttyAMA0,38400 kgdboc=ttyAMA0,38400
Start getty service
systemctl start getty@ttyAMA0
Enable on boot
systemctl enable getty@ttyAMA0.service
Creating the proper service link:
ln -s /usr/lib/systemd/system/getty@.service /etc/systemd/system/getty.target.wants/getty@ttyAMA0.service
Then connect :)
screen /dev/ttyUSB0 38400
Video
pacman -S xf86-video-fbdev
Adjustments are likely required to correct proper overscan/underscan and are easily achieved in boot/config.txt
in which many tweaks are set. To fix, simply uncomment the corresponding lines and setup per the commented instructions:
# uncomment the following to adjust overscan. Use positive numbers if console # goes off screen, and negative if there is too much border #overscan_left=16 overscan_right=8 overscan_top=-16 overscan_bottom=-16
Users wishing to use the analog video out should consult this config file which contains options for non-NTSC outputs.
A reboot is needed for new settings to take effect.