Băm xung (PWM) trên Raspberry Pi Pico

Kết nối phần cứng

Viết code

# Example using PWM to fade an LED.
import utime, _thread
from machine import Pin, PWM

led_red = PWM(Pin(14))
pwm_red_width = 65536
pwm_red_dir = True

led_green = PWM(Pin(13))
pwm_green_width = 65536
pwm_green_dir = True

led_yellow = PWM(Pin(12))
pwm_yellow_width = 65536
pwm_yellow_dir = True

led_red.freq(50)
led_green.freq(50)
led_yellow.freq(50)

is_change = True

button = Pin(17, Pin.IN)
last_time_stamp = utime.ticks_us()
def button_callback(pin):
    global is_change, last_time_stamp
    if utime.ticks_us() - last_time_stamp > 300000:
        last_time_stamp = utime.ticks_us()
        is_change = not is_change
        _thread.start_new_thread(task, (50, 0.05))
button.irq(trigger = Pin.IRQ_FALLING, handler = button_callback)

led_25 = PWM(Pin(25))
led_25.freq(50)
def task(n, delay):
    global led_25
    for duty in range(0, 65536, +80):
        led_25.duty_u16(duty)
        utime.sleep(0.001)
    for duty in range(65536, 0, -80):
        led_25.duty_u16(duty)
        utime.sleep(0.001)
    led_25.duty_u16(0)

while True:
    if is_change != True:
        utime.sleep(0.01)
        continue
    if pwm_red_dir:
        pwm_red_width += 20
    else:
        pwm_red_width -= 20
    
    if pwm_green_dir:
        pwm_green_width += 50
    else:
        pwm_green_width -= 50
        
    if pwm_yellow_dir:
        pwm_yellow_width += 100
    else:
        pwm_yellow_width -= 100
        
    if pwm_red_width < 0:
        pwm_red_dir = True
        pwm_red_width = 0
    if pwm_red_width > 65536:
        pwm_red_dir = False
        pwm_red_width = 65536
        
    if pwm_green_width < 0:
        pwm_green_dir = True
        pwm_green_width = 0
    if pwm_green_width > 65536:
        pwm_green_dir = False
        pwm_green_width = 65536
        
    if pwm_yellow_width < 0:
        pwm_yellow_dir = True
        pwm_yellow_width = 0
    if pwm_yellow_width > 65536:
        pwm_yellow_dir = False
        pwm_yellow_width = 65536
        
    led_red.duty_u16(pwm_red_width)
    led_green.duty_u16(pwm_green_width)
    led_yellow.duty_u16(pwm_yellow_width)
    
    utime.sleep(0.001)

Còn đây là kết quả