from machine import Pin, PWM
import time
pwm = PWM(Pin(13))  
pwm.freq(50)

'''
Duty cycle corresponding to the Angle
0°----2.5%----25
45°----5%----51.2
90°----7.5%----77
135°----10%----102.4
180°----12.5%----128
'''
angle_0 = 25
angle_90 = 77
angle_180 = 128

while True:
    pwm.duty(angle_0)
    time.sleep(1)
    pwm.duty(angle_90)
    time.sleep(1)
    pwm.duty(angle_180)
    time.sleep(1)