'''
Multithreading simple example in Raspberry Pi Pico
Adrianos Botis
'''
# Import Packages
import time, _thread, machine, utime
from machine import Pin, PWM

# Define Built in Temperature read sensor
sensor_temp = machine.ADC(4)
conversion_factor = 3.3 / (65535)


# Define the parallel task 
flag = False
def task(n,delay):
    global flag
    # Construct PWM object, with LED on Pin(25).
    pwm = PWM(Pin(25))

    # Set the PWM frequency.
    pwm.freq(1000)

    # Fade the LED in and out a few times.
    duty = 0
    direction = 1
    for _ in range(n):
     duty += direction
     if duty > 255:
        duty = 255
        direction = -1
     elif duty < 0:
        duty = 0
        direction = 1
     pwm.duty_u16(duty * duty)
     time.sleep(delay)
    flag = True

# Start the LED dimmer thread
_thread.start_new_thread(task,(4096,0.005))


# Main Loop to Read Temperature
while not flag:
    reading = sensor_temp.read_u16() * conversion_factor
    
    # The temperature sensor measures the Vbe voltage of a biased bipolar diode, connected to the fifth ADC channel
    # Typically, Vbe = 0.706V at 27 degrees C, with a slope of -1.721mV (0.001721) per degree. 
    temperature = 27 - (reading - 0.706)/0.001721
    print("Temperature: " + str(temperature) + " C")
    utime.sleep(0.05)