Differences

This shows you the differences between two versions of the page.

--- products:sbc:edge2:applications:gpio:pwm [2022/09/19 05:33]
nick removed
+++ products:sbc:edge2:applications:gpio:pwm [2022/12/02 02:19] (current)
ivan [Introduction]
@@ Line 2: / Line 2: @@
 ====== 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
+```
-{{page>products:sbc:common:applications:gpio:pwm&noheader}}

Khadas Docs

User Tools

Site Tools

Differences

Page Tools