达识科技全志H618核心板 - PWM输出

原创已于 2024-10-29 15:12:12 修改 · 961 阅读

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#科技

于 2024-10-29 14:55:33 首次发布

Linux5.4内核

使用PI11、PI12引脚作为PWM输出实例

修改设备树文件：/root/longan-h618/device/config/chips/h618/configs/1GB/linux-5.4/board.dts

增加PWM引脚描述：

注意：确保PI11、PI12两个引脚没有被其他地方占用

   pwm1_pin_a: pwm1@0 {
       pins = "PI11";
       function = "pwm1";
       drive-strength = <10>;
       bias-pull-up;
   };
   pwm1_pin_b: pwm1@1 {
       pins = "PI11";
       function = "gpio_in";
   };

   pwm2_pin_a: pwm2@0 {
       pins = "PI12";
       function = "pwm2";
       drive-strength = <10>;
       bias-pull-up;
   };
   pwm2_pin_b: pwm2@1 {
       pins = "PI12";
       function = "gpio_in";
   };

增加PWM设备节点：

&pwm1 {
   pinctrl-names = "active", "sleep";
   pinctrl-0 = <&pwm1_pin_a>;
   pinctrl-1 = <&pwm1_pin_b>;
   status = "okay";
};

&pwm2 {
   pinctrl-names = "active", "sleep";
   pinctrl-0 = <&pwm2_pin_a>;
   pinctrl-1 = <&pwm2_pin_b>;
   status = "okay";
};

修改设备树后，使用下面的命令控制输出PWM信号

#PWM1 PI11引脚

echo 1 > /sys/class/pwm/pwmchip0/export #导入PWM1 PI11引脚

echo 0 > /sys/class/pwm/pwmchip0/pwm1/enable #关闭PWM1输出

echo 100000 > /sys/class/pwm/pwmchip0/pwm1/period #设置频率

echo 50000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle #设置占空比50%

echo 1 > /sys/class/pwm/pwmchip0/pwm1/enable #打开PWM1输出

#PWM2 PI12引脚

echo 2 > /sys/class/pwm/pwmchip0/export #导入PWM2 PI11引脚

echo 0 > /sys/class/pwm/pwmchip0/pwm2/enable #关闭PWM2输出

echo 100000 > /sys/class/pwm/pwmchip0/pwm2/period #设置频率

echo 50000 > /sys/class/pwm/pwmchip0/pwm2/duty_cycle #设置占空比50%

echo 1 > /sys/class/pwm/pwmchip0/pwm2/enable #打开PWM2输出