import RPi.GPIO as GPIO
import time

# Cycle Through a range of simulated analog output voltages using PWM

print('GPIO Version', GPIO.VERSION)

print('Setting GPIO to BOARD Mode...n')
GPIO.setmode(GPIO.BOARD)

OUT_PIN1 = 33 # PWM PIN

OUTPUT_VOLTAGE = 3.3

MIN_VOLTAGE = 0.221
MAX_VOLTAGE = 0.310

BASE_DUTY = MIN_VOLTAGE / OUTPUT_VOLTAGE * 100.0
MAX_DUTY = MAX_VOLTAGE / OUTPUT_VOLTAGE * 100.0

MAX_INC = 5

print('PWM Setup ...')
GPIO.setup(OUT_PIN1, GPIO.OUT)
p = GPIO.PWM(OUT_PIN1, 100);
p.start(0)


print('Running')
while 1:
    for k in range(MAX_INC + 1):
        newDuty = (MAX_DUTY - BASE_DUTY)/MAX_INC*k + BASE_DUTY
        print(k,'  Changing to Duty Cycle:', newDuty, '%', '    Target: ', newDuty/100*3.3, 'V')
        p.ChangeDutyCycle(newDuty)
        time.sleep(3)