{"id":5938,"date":"2023-11-10T09:54:34","date_gmt":"2023-11-10T09:54:34","guid":{"rendered":"https:\/\/picockpit.com\/raspberry-pi\/?p=5938"},"modified":"2023-11-23T02:07:41","modified_gmt":"2023-11-23T02:07:41","slug":"exploring-microlua-lua-programming-for-rp2040","status":"publish","type":"post","link":"https:\/\/picockpit.com\/raspberry-pi\/exploring-microlua-lua-programming-for-rp2040\/","title":{"rendered":"Exploring MicroLua: Lua Programming for RP2040"},"content":{"rendered":"\n
\"Exploring<\/figure>\n\n\n\n

Have you ever wanted to delve into the world of Lua programming and explore the capabilities of the RP2040 microcontroller? Look no further \u2013 MicroLua offers an exciting opportunity to do just that! <\/p>\n\n\n\n

In this article, I want to dive into what MicroLua<\/a> is, how it works, and why I think it’s a super valuable tool for developers.<\/p>\n\n\n\n

I want to send a huge shout-out to Remy Blank<\/a> for developing MicroLua and sharing it with the world. Remy’s put it out with an MIT license (as Lua is itself), making MicroLua available for everyone. <\/p>\n\n\n\n

I’m really excited to use it in some future projects.<\/p>\n\n\n\n

What is MicroLua?<\/strong> What is an RP2040?<\/strong><\/h2>\n\n\n\n

So, MicroLua uses the Lua implementation and packages it. <\/p>\n\n\n\n

Lua is a dynamically-typed, multi-paradigm language. And it is, of course, one of the fastest scripting languages around. It’s also super small (the source code and documentation together take up 1.3 MB!)<\/p>\n\n\n\n

So it’s fast, it’s small, and it’s ideal when you want to embed something within larger applications.<\/p>\n\n\n\n

Lua has also got 21 highlighted keywords and a pretty straightforward syntax, so it’s relatively simple to learn.<\/p>\n\n\n\n

But, if you aren’t familiar, the immediate thing that everyone complains about with Lua is that it is a 1-based indexed language. And honestly, it gets me every single time.<\/p>\n\n\n\n

Here’s an example of Lua, so you can see it:<\/p>\n\n\n

\n
\"Lua
Credit: lua.org<\/a>.<\/figcaption><\/figure>\n<\/div>\n\n\n

Remy has designed MicroLua to program specifically for the RP2040 microcontroller. <\/p>\n\n\n\n

The RP2040 microcontroller is a Raspberry Pi in-house chip that drives a Pico<\/a>. However, Raspberry Pi also sells the RP2040 chip<\/a> separately. So, you can find the RP2040 in other boards as well, such as an Adafruit Feather<\/a>.<\/p>\n\n\n\n

MicroLua, then, packages Lua for these boards. In this context, MicroLua integrates the latest Lua interpreter (version 5.4) with interfaces for the Pico Software Development Kit<\/a> and includes a cooperative threading library.<\/p>\n\n\n\n

By putting the Lua interpreter together with the Pico interfaces, MicroLua lets you access the GPIO pins and timers. And I really love that Remy has included a cooperative threading library. So, if you’ve got a Pico, you can play around with both cores.<\/p>\n\n\n\n

Additionally, MicroLua has Fennel support, so if you have a love of Lisp (like me), you can still take advantage of MicroLua. Want to use a Lisp-like language with your Raspberry Pi Pico? Remy just made that ridiculously easy.<\/p>\n\n\n\n

Getting Started with MicroLua<\/strong><\/h2>\n\n\n\n

To set up MicroLua, you’re going to have to clone the repository<\/a>, initialize submodules, and follow the provided build instructions.<\/p>\n\n\n\n

The GitHub has the following code that’ll get a test suite up and running:<\/p>\n\n\n\n

<\/p>\n\n\n\n

<\/circle><\/circle><\/circle><\/g><\/svg><\/span><\/path><\/path><\/svg><\/span>
# <\/span>Configure<\/span> <\/span>the<\/span> <\/span>location<\/span> <\/span>of<\/span> <\/span>the<\/span> <\/span>Pico<\/span> <\/span>SDK<\/span>.<\/span> <\/span>Adjust<\/span> <\/span>for<\/span> <\/span>your<\/span> <\/span>setup<\/span>.<\/span><\/span>\n$<\/span> <\/span>export<\/span> <\/span>PICO_SDK_PATH<\/span>=<\/span>"<\/span>${HOME}\/pico-sdk<\/span>"<\/span><\/span>\n<\/span>\n# <\/span>Clone<\/span> <\/span>the<\/span> <\/span>repository<\/span> <\/span>and<\/span> <\/span>initialize<\/span> <\/span>submodules<\/span>.<\/span><\/span>\n$<\/span> <\/span>git<\/span> <\/span>clone<\/span> https<\/span>:<\/span>\/\/github.com\/MicroLua\/MicroLua.git<\/span><\/span>\n$<\/span> <\/span>cd<\/span> <\/span>MicroLua<\/span><\/span>\n$<\/span> <\/span>git<\/span> <\/span>submodule<\/span> <\/span>update<\/span> <\/span>--<\/span>init<\/span><\/span>\n<\/span>\n# <\/span>Connect<\/span> <\/span>a<\/span> <\/span>Picoprobe<\/span> <\/span>to<\/span> <\/span>the<\/span> <\/span>target<\/span>,<\/span> <\/span>on<\/span> <\/span>the<\/span> <\/span>UART<\/span> <\/span>and<\/span> <\/span>optionally<\/span> <\/span>on<\/span> <\/span>the<\/span> <\/span>debug<\/span><\/span>\n# <\/span>port<\/span>.<\/span> <\/span>Then<\/span> <\/span>view<\/span> <\/span>the<\/span> <\/span>Picoprobe<\/span>'<\/span>s UART connection in a separate terminal<\/span>.<\/span><\/span>\n# <\/span>The<\/span> <\/span>"<\/span>term<\/span>"<\/span> <\/span>script<\/span> <\/span>uses<\/span> <\/span>socat<\/span>.<\/span><\/span>\n$<\/span> <\/span>tools<\/span>\/<\/span>term<\/span> <\/span>\/<\/span>dev<\/span>\/<\/span>ttyACM0<\/span><\/span>\n<\/span>\n# <\/span>Build<\/span> <\/span>the<\/span> <\/span>unit<\/span> <\/span>tests<\/span>.<\/span><\/span>\n$<\/span> <\/span>cmake<\/span> <\/span>-<\/span>s<\/span> <\/span>.<\/span> <\/span>-<\/span>B<\/span> <\/span>build<\/span> <\/span>-<\/span>DPICO_BOARD<\/span>=<\/span>pico<\/span><\/span>\n$<\/span> <\/span>make<\/span> <\/span>-<\/span>j9<\/span> <\/span>-<\/span>C<\/span> <\/span>build<\/span>\/<\/span>lib<\/span><\/span>\n<\/span>\n# <\/span>Start<\/span> <\/span>the<\/span> <\/span>target<\/span> <\/span>in<\/span> <\/span>BOOTSEL<\/span> <\/span>mode<\/span> <\/span>and<\/span> <\/span>flash<\/span> <\/span>it<\/span> <\/span>with<\/span> <\/span>picotool<\/span>.<\/span><\/span>\n$<\/span> <\/span>picotool<\/span> <\/span>load<\/span> <\/span>-<\/span>v<\/span> <\/span>-<\/span>x<\/span> <\/span>build<\/span>\/<\/span>lib<\/span>\/<\/span>mlua_tests<\/span>.<\/span>elf<\/span><\/span>\n<\/span>\n# <\/span>Alternatively<\/span>,<\/span> <\/span>start<\/span> <\/span>the<\/span> <\/span>target<\/span> <\/span>in<\/span> <\/span>BOOTSEL<\/span> <\/span>mode<\/span> <\/span>and<\/span> <\/span>copy<\/span> <\/span>to<\/span> <\/span>its<\/span> <\/span>boot<\/span> <\/span>drive<\/span>.<\/span><\/span>\n$<\/span> <\/span>cp<\/span> <\/span>build<\/span>\/<\/span>lib<\/span>\/<\/span>mlua_tests<\/span>.<\/span>uf2<\/span> <\/span>\/<\/span>mnt<\/span>\/<\/span>RPI<\/span>-<\/span>RP2<\/span>\/<\/span><\/span><\/code><\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\n
Once you’ve got that, you’re good to go.<\/p>\n\n\n\n
I should mention that Remy has identified a few issues with MicroLua’s performance. First and foremost, the fact that the event dispatch latency is relatively slow and needs some improvement.<\/p>\n\n\n\n
So this is a project that’s very much alive and worth keep your eyes on.<\/p>\n\n\n\n
<\/p>\n\n\n\n
\n
Furthermore, if you go to the GitHub page<\/a>, Remy’s included a roadmap for things to add, like more bindings for the Pico SDK, a filesystem, and multi-chip communication. And Remy wants to improve threading performance, cross-core communication, and tune the garbage collector.<\/p>\n\n\n\n