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====== GPIO Header ======

====== GPIO usage examples ======

<WRAP important >
Please make sure that the GPIOs you want to use are not configured as other functions, if they are, you can follow [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]] to configure them as normal GPIOs.
</WRAP>

When you get the GPIO number, you can follow the steps below to control it. Here we take GPIO number ''465'' as an example.

===== Export GPIO =====

```shell
$ echo 465 | sudo tee /sys/class/gpio/export
```

===== Set-up GPIO direction =====

We can configure direction as input or output.

```shell
$ echo out | sudo tee /sys/class/gpio/gpio465/direction # Set GPIO output
$ echo in  | sudo tee /sys/class/gpio/gpio465/direction # Set GPIO input
```

===== Set GPIO value =====

```shell
$ echo 1 | sudo tee /sys/class/gpio/gpio465/value # Set GPIO output high
$ echo 0 | sudo tee /sys/class/gpio/gpio465/value # Set GPIO output low
```

===== Get GPIO value =====

```shell
$ cat /sys/class/gpio/gpio465/value # Get GPIO input value
```

===== Unexport GPIO ===== 

```shell
$ echo 465 | sudo tee /sys/class/gpio/unexport
```

===== Troubleshooting =====

If you got the similar error below, it means that the PIN you try to export is used for another function, you need to edit [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]] configuration file to set the PIN as normal GPIO.

```shell
$ echo 465 | sudo tee /sys/class/gpio/export 
tee: /sys/class/gpio/export: Invalid argument
```