March 2017
Intermediate to advanced
732 pages
15h 24m
English
Content preview from GNU/Linux Rapid Embedded Programming
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Getting access to GPIOs
Now let's look at how we can get access to GPIOs using both the command line (using Bash) and then using the C language.
Bash
Now it's time for an example. A very simple usage is the following one, where we use the gpio91 of the Wandboard to turn an LED on and off. The circuitry is reported in the following figure:
To control the LED, we must set the line as the output, so we should write out in the /sys/class/gpio/gpio91/direction file, but if we wish to set the LED to a precise state by default, it is better to write low, as show here:
root@wb:~# echo low > /sys/class/gpio/gpio91/direction
Note
You can now observe that the ...
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