circuitpython/examples/rp2/pwm_fade.py
Angus Gratton 861fbf6ab5 examples: Mark asm, pio, etc. as noqa: F821 (undefined-name).
These files all use decorators (@asm_thumb, @asm_pio) that add names to the
function scope, that the linter cannot see.

It's useful to clear them in the file not in pyproject.toml as example code
will be copied and adapted elsewhere, and those developers may also use
Ruff (we hope!)

Signed-off-by: Angus Gratton <angus@redyak.com.au>
2023-08-16 16:12:33 +10:00

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Python

# Example using PWM to fade an LED.
# Note: this does not work on Pico W because it uses Pin(25) for LED output.
# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
import time
from machine import Pin, PWM
# 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(8 * 256):
duty += direction
if duty > 255:
duty = 255
direction = -1
elif duty < 0:
duty = 0
direction = 1
pwm.duty_u16(duty * duty)
time.sleep(0.001)