phyduino/01_basics/fade/main.py

Fades the on-board LED up and down with PWM, about once every three seconds. The duty cycle goes from 0 (off) to 65535 (fully on) in 51 steps, 30 ms apart, then back down.

Uses

pwm()

# Fades the on-board LED up and down with PWM, about once every three seconds.
#
# The duty cycle goes from 0 (off) to 65535 (fully on) in 51 steps, 30 ms
# apart, then back down.
 
import time  # sleep() for pauses
 
import phyduino as mcu  # the Phyduino Pico library, used as mcu.<name>
 
STEP = 1285  # how much the brightness changes each time: 65535 / 51
 
led = mcu.pwm("LED")  # Puts the LED's pin into PWM mode and saves the control variable to the 'led' variable.
brightness = 0  # current duty cycle: 0 = off, 65535 = fully on
fade_amount = STEP  # added to brightness each pass: positive brightens, negative dims
 
while True:  # repeats until stopped: Interrupt in PyCharm, or mpremote soft-reset
    led.duty_u16(brightness)  # the fraction of the time the LED is on, out of 65535
    brightness += fade_amount  # one step brighter (or dimmer) for next time
    if brightness <= 0 or brightness >= 65535:
        fade_amount = -fade_amount  # at either end, turn round and go the other way
    time.sleep(0.03)  # 30 ms per step, so the fade is smooth