@Frank Thanks for your support. I tried it successfully in the Linux. But I still want to know how to active it in android. @goenjoy@Terry@jasonl Could you help me on this?
One more question. I want to connect the USB speaker to the VIM3 Android OS. Do I need to download the library for activing it? Or do I need to update kernel or somethings?
then input command as follow
echo 1 > /sys/class/pwm/pwmchip4/export
echo 1000000 > /sys/class/pwm/pwmchip4/pwm1/period
echo 500000 > /sys/class/pwm/pwmchip4/pwm1/duty_cycle
echo 1 > /sys/class/pwm/pwmchip4/pwm1/enable
you will see the pwm input by oscilloscope