Introduction - If you have any usage issues, please Google them yourself
PWM0 output 500 k square wave signal acquisition button data changes According to the key data volume range to determine whether there is a button, PWM output 500 KHZ square wave signals
To charging and discharging of capacitance, when a finger touch the metal parts Capacitance parameter changes, thus the voltage changes, using AD function detecting variation, knew with keys
Touch the button has the branch of resistance and capacitance