Getting Started with Raspberry Pi Pico W

Hardware Raspberry Pi Pico W / Guide

Getting Started with Raspberry Pi Pico W

Flash MicroPython, set up Thonny, and run your first program.

What is the Raspberry Pi Pico W?

The Raspberry Pi Pico W is a low-cost microcontroller board built around the RP2040 chip designed by Raspberry Pi. The "W" variant adds built-in WiFi (2.4 GHz 802.11n) via a CYW43439 chip.

Key specs:

  • Dual-core ARM Cortex-M0+ at up to 133 MHz
  • 264 KB SRAM
  • 2 MB on-board Flash
  • 26 multi-function GPIO pins
  • 2G— SPI, 2G— I2C, 2G— UART, 3G— ADC (12-bit)
  • Built-in WiFi (Pico W) and optional Bluetooth (Pico WH)
  • Micro-USB for power and programming
  • 3.3 V I/O (NOT 5 V tolerant)

Programming Languages

The Pico W supports three main approaches:

  • MicroPython ߀” easiest to start with, ideal for beginners and quick prototypes
  • CircuitPython ߀” similar to MicroPython, maintained by Adafruit
  • C/C++ SDK ߀” maximum performance and control, steeper learning curve

This guide focuses on MicroPython ߀” the most beginner-friendly path.

Flashing MicroPython

  1. Download the latest MicroPython .uf2 file for Pico W from micropython.org/download/rp2-pico-w/
  2. Hold the BOOTSEL button on the Pico W
  3. While holding BOOTSEL, plug in the USB cable
  4. The Pico W appears as a USB drive named RPI-RP2
  5. Drag and drop the .uf2 file onto the drive
  6. The drive disappears and the Pico W restarts ߀” MicroPython is now installed

Setting Up Thonny IDE

Thonny is the recommended IDE for MicroPython on Pico W:

  1. Download Thonny from thonny.org
  2. Open Thonny and go to Tools ߆’ Options ߆’ Interpreter
  3. Select MicroPython (Raspberry Pi Pico)
  4. Choose the correct COM port (or let Thonny detect it)
  5. Click OK ߀” Thonny connects to the Pico W REPL
from machine import Pin
from time import sleep

led = Pin("LED", Pin.OUT)   # "LED" is the built-in LED on Pico W (GPIO 25 on Pico)

while True:
    led.toggle()
    sleep(0.5)

Click Run (F5) in Thonny to run it. The green LED on the board will blink every 0.5 seconds.

Saving to the Pico W

  • Run ߆’ Run current script (F5): runs the file once from your PC
  • File ߆’ Save as ߆’ Raspberry Pi Pico: saves the file onto the Pico W's flash
  • Save your main program as main.py ߀” it will run automatically every time the Pico W powers on

The REPL

The REPL (Read-Eval-Print Loop) is an interactive Python prompt ߀” type commands and see instant results. In Thonny, click in the Shell area at the bottom.

>>> from machine import Pin
>>> led = Pin("LED", Pin.OUT)
>>> led.on()      # LED turns on immediately
>>> led.off()

Pin Numbering

Reference Example Notes
GPIO number Pin(15) Physical GPIO number, not pin header number
"LED" Pin("LED") Built-in LED (Pico W uses CYW43 GPIO, not a numbered pin)
Pin header Board printed numbers Physical positions 1߀“40 ߀” different from GPIO numbers

Always check the Pico W pinout diagram ߀” the physical pin numbers on the header are NOT the same as GPIO numbers.

Common First Steps

# Print to Thonny Shell
print("Hello, Pico W!")

# Read the unique board ID
import machine
print(machine.unique_id())

# Check available memory
import gc
gc.collect()
print(gc.mem_free(), "bytes free")
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