from machine import Pin, Timer, PWM

led1 = Pin('GP19', Pin.OUT)            # Create input and output Pin objects
led2 = Pin('GP18', Pin.OUT)
btn1 = Pin('GP17', Pin.IN, Pin.PULL_DOWN)
btn2 = Pin('GP16', Pin.IN, Pin.PULL_DOWN)
pwm = PWM('GP27',freq = 50)

def checkButtons(timer):               # Callback function
    led1.value(btn1.value())
    led2.value(btn2.value())
    if btn1.value():
        pwm.duty_u16(4825)
    elif btn2.value():
        pwm.duty_u16(1600)
    else:
        pwm.duty_u16(8050)

# Set up a timer to trigger every 100 ms
tmr = Timer(period = 100, callback = checkButtons)