Advanced Features and Commands
Zebra (VL-EPC-2701) Yocto Linux User Guide
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b0: b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ????????????????
c0: c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ????????????????
d0: d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ????????????????
e0: e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ????????????????
f0: f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd fe ff ???????????????.
GPIO
The following are some helpful notes on the use of J13 – User IO or General Purpose IO (GPIO):
•
Prior to using a pin, make sure its GPIO number has been exported to the
/sys/class/gpio/export
file.
•
The IO direction for a pin is set in the
/sys/class/gpio/gpio#/direction
file. Only
valid values are “in” or “out.”
•
Once the direction is set, you can only write to an “out” channel, i.e.
/sys/class/gpio/gpio#/value.
Writing to an "in" channel returns an error.
•
You can only read the value of an "in" channel. Reading the value of an "out" channel
always returns 0, but does not return any error.
•
More information can be found at
https://www.kernel.org/doc/Documentation/gpio/sysfs.txt
•
Some of the GPIO pins can be repurposed as PWM pins in software. Contact VersaLogic
for details.
