OrangePi Zero3: PWM test method

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Chapt 3. Instructions for use of Debian/Ubuntu Server and Xfce desktop system

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Chapter 3 contents

3.18.6. PWM test method

The development board can use up to 4 channels of PWM, and the positions of their pins are shown in the figure below:

Img 3.135

1) In the Linux system, the pwm is closed by default, and it needs to be opened manually to use it. The steps to open are as follows:

a. First run orangepi-config, normal users remember to add sudo permission

orangepi@orangepi:~$ sudo orangepi-config

b. Then select System

Img 3.136

c. Then select Hardware

Img 3.137

d. Then use the arrow keys on the keyboard to navigate to the position shown in the figure below, and then use the space to select the configuration corresponding to pwm

Img 3.138

Since the RX and TX pins of UART5 in the PWM1, PWM2 and 26pin interfaces are multiplexed, please make sure that the UART5 configuration is not selected (do not check ph-uart5) when turning on PWM1 and PWM2 (you need to select ph-pwm12). PWM3, PWM4 and the TX and RX pins in the debug serial port are multiplexed, so when using PWM3 and PWM4 (need to select ph-pwm34), please turn off the configuration of UART0 (need to select disable-uart0), after turning off UART0 The debug serial port cannot be used.

e. Then select 'Save' to save

Img 3.139

f. Then select 'Back'

Img 3.140

g. Then select 'Reboot' to restart the system to make the configuration take effect

Img 3.141

2) After restarting, the PWM test can be started

Please execute the following commands under the root user.

a. Enter the following command on the command line to make pwm1 output a 50Hz rectangular wave

root@orangepi:~# echo 1 > /sys/class/pwm/pwmchip0/export
root@orangepi:~# echo 20000000 > /sys/class/pwm/pwmchip0/pwm1/period
root@orangepi:~# echo 1000000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
root@orangepi:~# echo 1 > /sys/class/pwm/pwmchip0/pwm1/enable

b. Enter the following command on the command line to make pwm2 output a 50Hz square wave

root@orangepi:~# echo 2 > /sys/class/pwm/pwmchip0/export
root@orangepi:~# echo 20000000 > /sys/class/pwm/pwmchip0/pwm2/period
root@orangepi:~# echo 1000000 > /sys/class/pwm/pwmchip0/pwm2/duty_cycle
root@orangepi:~# echo 1 > /sys/class/pwm/pwmchip0/pwm2/enable

c. Enter the following command on the command line to make pwm3 output a 50Hz rectangular wave

root@orangepi:~# echo 3 > /sys/class/pwm/pwmchip0/export
root@orangepi:~# echo 20000000 > /sys/class/pwm/pwmchip0/pwm3/period
root@orangepi:~# echo 1000000 > /sys/class/pwm/pwmchip0/pwm3/duty_cycle
root@orangepi:~# echo 1 > /sys/class/pwm/pwmchip0/pwm3/enable

d. Enter the following command on the command line to make pwm4 output a 50Hz square wave

root@orangepi:~# echo 4 > /sys/class/pwm/pwmchip0/export
root@orangepi:~# echo 20000000 > /sys/class/pwm/pwmchip0/pwm4/period
root@orangepi:~# echo 1000000 > /sys/class/pwm/pwmchip0/pwm4/duty_cycle
root@orangepi:~# echo 1 > /sys/class/pwm/pwmchip0/pwm4/enable

Img 3.142

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