from machine import Pin,PWM,ADC 
from time import sleep
f=20000  #0 to 78125


l=PWM(Pin(23,mode=Pin.OUT),f)
b=Pin(2,mode=Pin.IN)
pot=ADC(Pin(12,mode=Pin.IN))
pot.width(ADC.WIDTH_10BIT)   #9-511   10-1023   11-2047   12-4095(default)
pot.atten(ADC.ATTN_11DB)   #11 --> 3.3V  5 --> 2V  2 -->V  1.5 --> 3.3V(maximum voltage provided to the analog pin used such that 0=0v and x=yV)
while True:
    val2=pot.read();
    val=b.value();
    if(val):
        l.duty(val2);