MicroPython Basics Compact Reference

A vocabulary reference of MicroPython functions, hardware APIs, modules, and code patterns.

print()

print("Hello") — display text.

Variables

x = 10; name = "LED"; on = True

if / elif / else

if x > 5: …

for / range

for i in range(10): print(i)

while

while True: …

Functions

def add(a, b): return a + b

Lists

items=[1,2,3]; items.append(4); items[0]

Dictionaries

d={"name":"LED"}; d["name"]

try / except

try: … except Exception as e: print(e)

len(x)

Number of items/characters.

int(x)

Convert to integer.

float(x)

Convert to float.

str(x)

Convert to string.

bool(x)

Convert to Boolean.

range()

Generate integer sequences.

enumerate()

Iterate with an index.

min() / max()

Smallest/largest value.

sum()

Add values.

abs()

Absolute value.

round()

Round a number.

Pin(pin, mode)

Create a GPIO pin. Example: Pin(2, Pin.OUT).

pin.value()

Read or set digital state.

pin.on() / pin.off()

Set output high/low where supported.

pin.toggle()

Toggle output where supported.

Pin.IN / OUT

Input/output modes.

Pin.PULL_UP / PULL_DOWN

Internal pull resistors where supported.

pin.irq()

Run a callback on a pin interrupt.

PWM(Pin(…))

Generate PWM output.

pwm.freq(hz)

Set/read PWM frequency.

pwm.duty_u16(value)

Set duty from 0–65535 where supported.

pwm.duty_ns(ns)

Set pulse width in nanoseconds where supported.

pwm.deinit()

Stop PWM.

ADC(Pin(…))

Read analog input.

adc.read_u16()

Read ADC as a 16-bit value where supported.

I2C(…)

Communicate with I2C devices.

i2c.scan()

Find I2C device addresses.

i2c.readfrom()

Read I2C bytes.

i2c.writeto()

Write I2C bytes.

SPI(…)

Communicate with SPI devices.

UART(…)

Serial communication.

Timer(…)

Run callbacks periodically.

machine.reset()

Reset the board.

time.sleep(s)

Pause for seconds.

time.sleep_ms(ms)

Pause for milliseconds.

time.sleep_us(us)

Pause for microseconds.

time.ticks_ms()

Monotonic millisecond counter.

time.ticks_us()

Monotonic microsecond counter.

time.ticks_diff(a,b)

Safely calculate tick differences.

import math

Math library.

math.sqrt(x)

Square root.

math.sin/cos/tan(x)

Trigonometry.

math.pi

$$\pi$$

math.floor/ceil(x)

Round down/up.

import random

Random-number library.

random.randint(a,b)

Random integer from a through b.

random.random()

Random float from 0 to 1.

open(path, mode)

Open a file: open("test.txt","w").

f.read()

Read file.

f.write(data)

Write data.

f.close()

Close file.

os.listdir()

List files/directories.

os.remove(path)

Delete a file.

json.dumps(x)

Convert object to JSON.

json.loads(s)

Parse JSON.

LED blink pattern

from machine import Pin; from time import sleep; led=Pin(2,Pin.OUT); led.value(1); sleep(1); led.value(0)

Button pattern

button=Pin(15,Pin.IN,Pin.PULL_UP); pressed=(button.value()==0)