MicroPython Function Library

WARNING

Machine - Hardware Related Functions

Pin Class

machine.Pin(id, mode=None, pull=None, value)

Pin object constructor

• id: GPIO number (0-29 for Pico)
• mode: Pin mode, options: None, Pin.IN(0), Pin.OUT(1), Pin.OPEN_DRAIN(2)
• pull: Internal pull-up/down resistor (only valid in input mode), options: None, Pin.PULL_UP(1), Pin.DOWN(2)
• value: Port value in output or open-drain mode (0 for low, 1 for high)

Pin.init(mode=None, pull=None)

Reinitialize GPIO port

Pin.value([x])

• Returns GPIO port value when no parameter is given
• Writes value to GPIO port when parameter 0/1 is provided

Pin.toggle()

Toggles port state in output or open-drain mode

Example: LED blinking

from machine import Pin
import time
led = Pin(25, Pin.OUT)
while True:
    led.toggle()
    time.sleep(1)  # Toggle LED every second

Pin.irq(handler=None, trigger=(Pin.IRQ_FALLING|PIN.IRQ_RISING))

External interrupt function

• handler: Callback function when interrupt triggers
• trigger: Interrupt trigger condition (edge/level triggered)

Other Functions

For output/open-drain mode:

• Pin.low(), Pin.off(): Set port to low voltage
• Pin.high(), Pin.on(): Set port to high voltage

Example: LED Control

from machine import Pin
import utime
# Button on GPIO15, input mode with pull-up
button_num = 15
button = Pin(button_num, Pin.IN, Pin.PULL_UP)
# Onboard LED on GP25, external LED on GP16
led1_num = 25
led2_num = 16
led1 = Pin(led1_num, Pin.OUT)
led2 = Pin(led2_num, Pin.OUT)

while True:
    led2.off()  # Turn off external LED
    if button.value() == 0:  # Check if button pressed (0 when pressed)
        utime.sleep(0.01)
        if button.value() == 0:  # Software debounce
            led1.toggle()  # Toggle onboard LED
            led2.on()  # Turn on external LED (GP16 high)
            print("The button is pressed.")
            while button.value() == 0:
                # Wait while button remains pressed (external LED stays on)
                utime.sleep(0.01)

PWM Class

machine.PWM(pin)

Reinitialize specified GPIO as PWM output

• pin: Pin class object

PWM.deinit()

Deinitialize PWM, stop PWM output

PWM.freq([value])

Set PWM frequency (in Hz), automatically calculates divider and TOP register values

PWM.duty_u16([value])

Set duty cycle

• value: Duty cycle ratio [0,65536], calculates corresponding value for CC register

PWM.duty_ns([value])

Set high-level duration per cycle in nanoseconds

Example: Breathing LED

from machine import Pin, PWM
import time

led = PWM(Pin(25))  # Initialize onboard LED as PWM
led.freq(1000)  # Set frequency
led_duty = 0  # Initial value
led_direction = 1  # Step size

while True:
    led_duty += led_direction  # Increase/decrease duty cycle
    if led_duty >= 100:  # Max
        led_duty = 100
        led_direction = -1
    elif led_duty <= 0:  # Min
        led_duty = 0
        led_direction = 1
        
    led.duty_u16(int(led_duty * 655.36))  # Convert ratio to value
    
    if led_duty % 5 == 0:
        print(led_duty)  # For monitoring
        
    time.sleep(0.01)
    # 2-second cycle

ADC Class

machine.ADC(id)

Initialize as ADC object

• id: Can be GPIO or ADC channel (GPIO must support ADC when using Pin object)
• Channels 0-3: Pico GPIO 26-29
• Channel 4: Internal temperature sensor

ADC.read_u16()

Read ADC channel value [0,65525]