OLIMEX© 2015
A20-OLinuXino-MICRO user's manual
Note that you can export GPIOs in range with:
for i in `seq 1 1 230`; do echo $i > /sys/class/gpio/export; done
2. Set input/output GPIO 49
2.1 Set input:
echo "in" > /sys/class/gpio/gpio49_ph9/direction
2.2 Set output:
echo "out" > /sys/class/gpio/gpio49_ph9/direction
3. Set value or read value GPIO 49
3.1 Set value:
echo 0 > /sys/class/gpio/gpio49_ph9/value
echo 1 > /sys/class/gpio/gpio49_ph9/value
3.2 Read input:
cat /sys/class/gpio/gpio49_ph9/value
4. Unexport GPIO 49 when finished
echo 49 > /sys/class/gpio/unexport
A very good document on GPIO usage might be found here:
http://www.py6zgp.com/download/A20-GPIO.pdf
– the document was created by Dr. Guido Pelz.
2.10 I2C and SPI under Debian
I2C and SPI are both supported in the latest Debian releases. There is respective kernel support for
both. There is a python module called pyA20 might be found here:
https://pypi.python.org/pypi/pyA20
At the same web address you would also find a set of examples on how module is used.
2.11 Software support
We maintain Linux and Android images for SD card which might be downloaded for free and
modified as the user wishes. The latest images and updates are featured at the wiki article of the
device:
https://www.olimex.com/wiki/A20-OLinuXino-MICRO
We usually try to provide details on how to build the Linux and the Android images at our
wordpress page:
Another useful place is the Olimex forums where a lot of people share their experience and advice:
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