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ENG | Raspberry Pi Pico and MicroPython, Getting started

Explore the basics of Raspberry Pi Pico and MicroPython. Learn how to set up your board, install MicroPython, and start programming with a simple LED example.

Posted Updated
By Pavel Peřina
7 min read
ENG | Raspberry Pi Pico and MicroPython, Getting started

Introduction

Spring

Spring is here and with it comes Pi day! Best time to try a new microcontroller: Raspberry Pi Pico 🙂

What is Raspberry Pi Pico

The Raspberry Pi Pico is a low-cost microcontroller board designed by the Raspberry Pi Foundation. While modest in computing power compared to modern processors, it offers sufficient performance for many hobbyist projects and basic embedded systems, especially considering its price point. The Pico is well-suited for tasks like reading sensors, controlling LEDs, handling basic I/O operations, and running simple real-time applications such as audio processing.

One of the standout features of the Raspberry Pi Pico is its support for MicroPython, a lean and efficient implementation of the Python 3 programming language optimized for microcontrollers. MicroPython allows developers to write code using the familiar and user-friendly Python syntax, while taking advantage of the Pico’s hardware capabilities. This may be beneficial for those who are not familiar with C/C++ and setting up build environments.

Raspberry Pi Pico 2 was released in late summer 2024 (and version with WiFi later in November). It promises more RAM, bigger flash memory, somewhat faster RP2350 processor (especially for floating point operations and/or using proper compiler), slightly lower power consumption, power efficient sleep mode. On some eshops, this made original Pico even cheaper. It does not change anything mentioned in this article. Well … vscode extension, but this is likely temporary issue.

For compatibility reasons it still has MicroUSB connector.

Specifications

 Pico (RP2040)Pico 2 (RP2350)
Clock speed133MHz150MHz
SRAM264K520K
Arm Cores2x Arm Cortex-M0+2x Arm Cortex-M33
RISC-V Cores-2x Hazard3
Flash Memory2M4M
Extras floating point support (Arm cores)
security features

What is not Raspberry Pi Pico

It’s not a single board computer (SBC) similar to Raspberry Pi or Raspberry Pi Zero, but a completely different product. It cannot run operation system. It’s a microcontroller with completely different goal, more similar to popular Arduino, STM32, ESP32, nRF52840 and alike.

What is MicroPython

MicroPython is a compact and efficient implementation of the Python 3 programming language designed specifically for microcontrollers and embedded systems. It brings the simplicity and readability of Python to the world of low-level hardware programming, allowing developers to write code that interacts directly with sensors, actuators, and other peripherals.

While MicroPython shares most of the syntax and features of standard Python, it has been optimized for resource-constrained environments, making it an ideal choice for microcontrollers like the Raspberry Pi Pico. With MicroPython, you can leverage the power of Python to quickly prototype and develop applications for a wide range of projects, from Internet of Things (IoT) devices to robotics and automation systems.

By combining the ease of use and productivity of Python with the low-level control of microcontrollers, MicroPython offers developers a simple approach to embedded programming.”.

Installing MicroPython on Raspberry Pi Pico

  • Connect to Pico using microUSB cable

  • Let’s see what official documentation says:

    Raspberry Pi Pico Python SDK PDF, page 4:

    Raspberry Pi Pico has a BOOTSEL mode for programming firmware over the USB port. Holding the BOOTSEL button when powering up your board will put it into a special mode where it appears as a USB Mass Storage Device. First make sure your Raspberry Pi Pico is not plugged into any source of power: disconnect the micro USB cable if plugged in, and disconnect any other wires that might be providing power to the board, e.g. through the VSYS or VBUS pin. Now hold down the BOOTSEL button, and plug in the micro USB cable (which hopefully has the other end plugged into your computer).

    A drive called RPI-RP2 should pop up. Go ahead and drag the MicroPython firmware.uf2 file onto this drive. This programs the MicroPython firmware onto the flash memory on your Raspberry Pi Pico.

    It should take a few seconds to program the UF2 file into the flash. The board will automatically reboot when finished, causing the RPI-RP2 drive to disappear, and boot into MicroPython.

  • Ok. Pico will appear as a 128MB USB drive. If not, disconnect it and plug it again while holding BOOTSEL button.
  • Download MicroPython for your Raspberry Pico (version 1 or 2 with or without WiFi).
  • Now you can upload MicroPython by copying it to small drive.
    Copy Micropython
    • It will immediatelly restart and USB drive will disconnect and won’t be available.
  • Windows only: Download PuTTY e.g. via Windows Store.
  • Determine to which serial port Pico is attached, e.g. using Device manager on Windows. On Linux try ls -la /dev/serial/by-id (for me it’s /dev/ttyACM0)
  • Connect to Pico (Serial port, COM5 depends on your config, speed may be 9600 or 115200). On Linux type minicom -D /dev/ttyACM0.
    PuTTY setup
  • Terminal will likely appear, if there is program running, try to abort it using Ctrl+C. Type help() to get some basic, but useful help
    PuTTY MicroPython help
  • Now you can try to play with LED using Python shell (or REPL - Read, Eval, Print Loop).
    Minicom MicroPython

MicroPython in Visual Studio Code

As of late October 2024, this does not work as described with Raspberry Pico 2 on Linux. Precisely MicroPico: Configure MicroPico Project does nothing except opening terminal. Run current file on Pico works. Project likely not.

Also there is now official extension Raspberry Pi Pico which seem to contain both C++ and MicroPython support.

  • Get Visual Studio Code
  • Install MicroPico Extension (former name Pico-W-Go). If you have Remote-SSH extension, make sure to install it on a local computer)
    Install extension
  • Now you can basically click on github link above or read extension page, but step-by-step guide is
    1. Create new folder (e.g c:\dev-py\mp2 for micropython, test2)
    2. Configure project (Ctrl+Shift+P for commands, search MicroPico: Configure project) This will create some files and connect to Pico
    3. Create new file (e.g. test.py)
    4. Paste example code (from VS Code extension readme)
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      from machine import Pin
from utime import sleep

pin = Pin("LED", Pin.OUT)

print("LED starts flashing...")
while True:
    try:
        pin.toggle()
        sleep(1) # sleep 1sec
    except KeyboardInterrupt:
        break
pin.off()
print("Finished.")
    5. Run it (Ctrl+Shift+P: MicroPico: Run current file on Pico) or using icon in the status bar.
    6. To make your program run at boot, rename file to main.py choose MicroPico: Upload project to Pico. However VS Code always retakes control when project is open for editing purposes.
    7. You can download files from Pico, but preferably do it into new, empty directory
    8. Extra: try MicroPico: Help > Show Pico Pin Map

Pinout

  • Pin 40: VBUS 4.5-5.5V from USB BUS
  • Pin 39: VSYS 1.8-5.5V input voltage
  • Pin 37: 3V3_EN ?
  • Pin 36: 3V3 3.3V output, up to 300mA

Summary

This article describes setting of MicroPython and first steps. At the moment I haven’t tried anything but LED, I have only brief idea how to work with sensors and so on and I’m not familiar with powering it by other ways than USB cable to computer.

C++ and it’s possibilities are uncharted territory which waits to be explored in the follow up article.

A key benefits of this hardware is that it does not need any specific software to upload program - just hold the BOOTSEL button during the boot, upload uf2 file and that’s all. Well. MicroPython uses some tricks for uploading file, and there’s Visual Studio Code extension for that.

It’s also certainly more capable than Arduino as it supports DMA transfers etc.

And more flexible as it can use MicroPython, C and likely FreeRTOS.

Also it’s by far cheaper than Arduino, although there are 3rd party Arduino clones and also option to build your own, using ATMega chip, few electronic parts, and to use advantages of Arduino IDE.

Resources

Changes

  • 2024-10-30: RPI Pico 2 and Linux mentioned.
  • 2024-10-31: Slight modifications.
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This post is licensed under CC BY 4.0 by the author.