使用开发板为天嵌AM335X，PWM输入引脚为GPMC_A3，PWM设备文件是 /sys/class/pwm/ehrpwm.1:1 ，在QT界面中可以输入占空比和周期-The use of embedded development board for the day AM335X, PWM input pin GPMC_A3, PWM device file is /sys/class/pwm/ehrpwm.1:1 , in QT interface, you can enter duty c

通过按键控制PWM占空比，包括驱动和测试程序-Control PWM duty cycle by key，include driver and test program