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How to control Devices from user space (command line)
Introduction
This page lists the most important devices and drivers that are specific to this board. And how they can be accessed from user space.
Display
Touch Screen
is mapped to
/dev/input/touchscreen
pen down status can be read through
cat /sys/devices/virtual/gpio/gpio160/value
LCD
can be selected by adding "omapdss.def_disp=lcd" to the boot args. This is done by "setenv defaultdisplay lcd" in our boot.scr.
To disable/enable (power down/up) the LCD (state=0: off, state=1: on)
echo "$state" >/sys/devices/omapdss/display2/enabled
For more information about switching the DSS2 system, please refer to http://processors.wiki.ti.com/index.php/DSS2_SYSFS_Examples
DVI - on Beagleboard only!
can be selected by adding "omapdss.def_disp=dvi" to the boot args
power (state=0: off, state=1: on)
echo $state >/sys/devices/virtual/gpio/gpio170/value
Video out (can't use headset mic)
can be selected by adding "omapdss.def_disp=venc" to the boot args
To disable/enable (power down/up) the LCD (state=0: off, state=1: on) in the DSS system:
echo "$state" >/sys/devices/omapdss/display1/enabled
The video out amplifier is automatically controlled by enabling, but can be controlled independently through (state=0: off, state=1: on)
echo $state >/sys/devices/virtual/gpio/gpio23/value
NOTE: while gpio23 is "1", you can't use the headset microphone.
Headset out / AUX in
The video amplifier is controlley by (state=0: AUX IN, state=1: AUX OUT)
echo $state >/sys/devices/virtual/gpio/gpio55/value
If enabled, you can't use the AUX IN
Backlight
power (state=0: off, state=1: on)
echo $state >/sys/devices/virtual/gpio/gpio57/value
GPS
power (state=0: off, state=1: on) - you may have to switch on/off/on to reset the GPS chip
echo $state >/sys/devices/virtual/gpio/gpio145/value
device file (use 9600 baud)
cat /dev/ttyS1
if the external antenna is active can be determined through
cat /sys/devices/virtual/gpio/gpio144/value # 1=ext. ant.
AUX and Power button
button status can be read through
cat /sys/devices/virtual/gpio/gpio7/value # 0=AUX pressed
The AUX button is available through the TPS driver as a key event. The power button is available through the TPS driver as a key event.
LEDs are switched through the TCA6507 driver
**** FIXME **** echo $state >/sys/devices/virtual/gpio/gpio70/value # AUX - red echo $state >/sys/devices/virtual/gpio/gpio71/value # AUX - green echo $state >/sys/devices/virtual/gpio/gpio78/value # POWER - red echo $state >/sys/devices/virtual/gpio/gpio79/value # POWER - green
I2C
Depending on the exact version of the board there may be I2C devices (besides the touch screen controller).
You should install http://packages.debian.org/de/lenny/i2c-tools resp. http://www.lm-sensors.org/wiki/I2CTools
Commands
There should be the following commands
- i2cdetect
- i2cdump
- i2cget
- i2cset
ADCs of the TPS65950
are available through /dev/twl4030-madc and the madc driver. See e.g. http://www.jumpnowtek.com/index.php?option=com_content&view=article&id=79&Itemid=91
ADC0: BATID (default: 0V) ADC1: BATTEMP (default: 1.8V) ADC2: ADC2IN (default: 0V) ADC7: MICSENSE (no headset / short / headset)