The landlord Published in: 13:31:06 2016-01-19
Today, the main introduction of the most basic function of ---LED DragonBoard. (Low speed extension connection)
The red frame section below is the low speed expansion port (J8).
First you have to have a Dragonboard410c development board, and then you need to prepare a LED light as well as the keyboard, HDMI display and power supply.
To board programming, two kind of writing style, one is through the SD card programmer system, another is through FastBoot programmer. Before I introduced to you, we can look at the previous post.
Let's look at the low speed extension pin in the board position
Physical connection diagram
According to pin diagram, connect pin23 (APQ_GPIO_36) and Pin1 (GND) to LED. Specific connection to see the figure below
The LED lamp lights out procedure
Execute the following command to number export GPIO.
1.echo 36 > /sys/class/gpio/export
Executed in the /sys/class/gpio/ directory will generate gpio36 directory
The generated gpio36 directory will have the following nodes:
Direction is used to set the input or output, value used to set the level of high and low.
Set to output mode
Execute the following command to modify the gpio36 mode for output:
1.echo "out" > /sys/class/gpio/gpio36/direction
Output high level through the following command:
1.echo "1" > /sys/class/gpio/gpio36/value
At this time the output voltage is 1.8V.
The following command out of LED:
1.echo "0" > /sys/class/gpio/gpio36/value
At this time, the output voltage is changed to 0V.
#1 Score: 0 Reply to: 08:30:21 2016-01-29
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