~~tag>Edge2 PWM~~

====== Edge2 PWM ======

===== Introduction =====

This page introduces the usage of hardware PWM, and leads you to control the hardware PWM on the [[products:sbc:edge2:applications:gpio:40pin-header|16-pin Header]] .

<WRAP important >
For Edge2, in order to use the PWM function, you need to attach the IO extension board.
</WRAP>
===== PWM Information =====

|           ^  PWM       ^  PIN  ^  GPIO Name  ^  GPIO Number  ^  DT Overlays Node  ^  Device Node              ^
^  Edge2    |  PWM14     |  13   |  GPIO3_C2   |  114          |   edge2-io-pwm     |  /sys/class/pwm/pwmchip2  |


===== Enable PWM =====

In order to use the PWM, you need to enable the PWM function via [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]].


Edit ''/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlay.env'' to add pwm node to ''fdt_overlays'' node if it doesn't exist.


You need to add ''edge2-io-pwm'' to node ''fdt_overlays'' if it doesn't exist to enable ''PWM14''.

```shell
fdt_overlays=edge2-io-pwm

```

After reboot, you will see the pwm device node.

```shell
$ ls /sys/class/pwm/pwmchip2
device  export  npwm  power  subsystem  uevent  unexport
```

===== Disable PWM to Use GPIO =====

If you want to use normal GPIO instead of PWM, you can remove the PWM node in [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]].

===== Control PWM =====

**Enable PWM:** 

```shell
echo 0 | sudo tee /sys/class/pwm/pwmchip2/export
echo 1000000 | sudo tee /sys/class/pwm/pwmchip2/pwm0/period
echo 500000 | sudo tee /sys/class/pwm/pwmchip2/pwm0/duty_cycle
echo 1 | sudo tee /sys/class/pwm/pwmchip2/pwm0/enable
```

Use an oscilloscope to check if the pins have been successfully enabled.

{{products:sbc:common:applications:gpio:pwm-oscilloscope.png|pwm-oscilloscope}}

<WRAP info >
If you use an oscilloscope to view the PWM waveform, remember that the SBC and the oscilloscope need to share the same GND (ground).
</WRAP>

**Disable PWM:**

```shell
echo 0 | sudo tee /sys/class/pwm/pwmchip2/pwm0/enable
```