Embedded Python: MicroPython Toolkits [Hackaday]

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Last time, I talked about how MicroPython is powerful and deserving of a place in your toolkit, and it made for a lively discussion. I’m glad to see that overall, MicroPython has indeed been getting the recognition it deserves – I’ve built a large number of wonderful projects with it, and so have people I’ve shown it to!

Sometimes I see newcomers dissatisfied with MicroPython, because the helper tools they initially pick don’t suit it well. For instance, they try and start out with a regular serial terminal application that doesn’t fit the MicroPython constraints, or a general IDE that requires a fair bit of clicking around every time you need to run your code. In particular, I’d make sure that you know your options no matter whether you prefer GUI or commandline – both have seriously nice tools for MicroPython use!

The main problem to be solved with MicroPython is that you have a single serial port that everything happens through – both file upload and also debugging. For ESP8266/32-based boards, it’s a physical serial port, and for chips like RP2040 and ESP32-S* where a hardware USB peripheral is available, it’s a virtual one – which makes things harder because the virtual port might get re-enumerated every now and then, possibly surprising your terminal application. If you want to upload a program of yours, you need to free up the serial port, and to see the program’s output, you will need to reopen that port immediately after – not a convenient thing to do if you’re using something like PuTTy.

So, using MicroPython-friendly software is a must for a comfortable hacking experience. What are your options?

Power Of Thonny And Friends

Whether you’re primarily a GUI user, or you’re teaching someone that is, Thonny is undoubtedly number one in MicroPython world – it’s an IDE developed with Python in mind, and it has seriously impressive MicroPython integrations. Your board’s terminal is being managed as if effortlessly in the background – just open your files in different tabs as you normally do, and press the Run button sometimes.

Expecting more? There is more – basically anything MicroPython adjacent you’d do from commandline, is present in Thonny in a comfortable way. For instance, are you working with an ESP32 board that doesn’t yet have a MicroPython image in its flash? Lucky you, there’s an esptool integration that lets you flash an image into your MCU through a dialog box. Want debugging? There’s single-step debugging that works in an intuitive user-friendly way – you’d find this pretty hard to happen from console apart from specially engineered print statements, but Thonny delivers.

Not looking to pick a new IDE? There are VSCode extensions. Arduino IDE more your jam? Yeah, well, remember how Arduino has a MicroPython IDE now? It’s decently usable, so if you got used to the Arduino keybindings, you might like it. More of a commandline user? You’ve got a good few options, then, and they are similarly powerful.

Mpremote And Ampy

Rather use the terminal? Maybe IDEs are too clunky for you and the terminal window’s cleanliness provides for a distraction-free environment you can only dream about, maybe it’s just the thing you’ve used your entire life, or maybe you’re even debugging a MicroPython device over an SSH connection? mpremote is the tool to save you.

mpremote is part of the MicroPython project, it’s developed alongside the project, and it’s got plenty of killer features to show for it. It includes an “inline” terminal emulator that lets you access REPL effortlessly to see your code’s results and interact with the variables afterwards, correctly managing things like Ctrl+C so you can interrupt your code if needed and still poke at its variables in the REPL. You can also explore the MicroPython filesystem Linux-style with ease, and, most importantly, you can mount your current directory up to it with mpremote mount, and mpremote will send files to your board as the on-MCU interpreter requests them.

Overall, mpremote offers a seriously comfortable environment for iterating on MicroPython code lightning quick. Without it, you would need to reopen the serial port each time you need to upload a new file – here, you can just chain a bunch of commands together and mpremote will dutifully do the serial port juggling needed to get you there.

In addition to that, you can see that mpremote is designed to help you with awkward-to-do things you didn’t know you needed to do. Need to sync your board’s RTC time with your computer’s time? That’s a mpremote rtc command away. Want to access the MicroPython package manager? That’s mpremote mip. Your board needs to switch into bootloader mode? No need to fiddle with buttons, just use mpremote bootloader. In short, mpremote is a MicroPython powerhouse for everyone who’s most comfortable in a terminal window.

There is an alternative here, too: ampy, a personal choice of mine, which I use combined with screen. Ampy is a tool initially designed by Adafruit, and it’s more barebones – I like it because I have control of what’s happening when I issue a command to a software, keeping my MicroPython devices in a known state at all times. On the other hand, it does require jugging the serial port on your own, so when I need to update my code, I exit screen, run the ampy command, then re-enter screen again. I regularly work with large MicroPython files that also import static library files that don’t change for months, however, so having control of the upload process seems to save me a fair bit of time.

There are caveats, of course – the major one is, when using screen in serial terminal mode, you need to press Ctrl+A k y (kill window) instead of Ctrl+A d to detach the screen session. If you do the detach instead, as you might be used to with screen, the serial port will remain open until you unplug the device or kill the screen process, and ampy will fail mysteriously.

Summary

I hope this toolkit overview helps you make sure you’re using exactly the kind of MicroPython environment that works for you – while compiling it, I’ve learned some nuances myself! Next time, we shall talk about CircuitPython – a MicroPython fork that has grown into a contender in the educational Python space, and how it is different from MicroPython in a number of crucial ways you deserve to know about.