An RP2040 microcontroller development board with an integrated macropad that lets you control GPIOs with keyboard keys on a single PCB, plus a custom BASIC interpreter and disk operating system.
@nicholas1023
on
Macro Microcontroller 2
This ship focuses more on the firmware and documentation of my project! For this ship, I made a PC-like system for my microcontroller, including a DOS-like firmware which boots from a BIOS I written myself. The effect of the BIOS made my device look really like an actual usable computer from the 80’s and the DOS allows it to be used as a PC! After this, I would try to implement a filesystem, so that it can actually be used to store files, as it has 15 MB of extra flash!
Here is the DOS demo video: https://nicholas1023.github.io/macro-microcontroller-2/assets/dos-demo.mp4
@nicholas1023
on
Macro Microcontroller 2
38m 12s logged
In this devlog, I added a new page for the DOS setup and usage guide!
As the pages in my documentation site are getting more and more, I decided to create a folder, and move the guides in, so the navbar would be less cluttered.
One problem I faced though was the CSS and icons not loading in the guide, as the directories were getting a little complicated, given that I am using the /docs directory in my repo for the site, which makes URLs without the full path returning 404. After a few commits (localhost was not using /docs as the root of the site), I finally found the right URL!
@nicholas1023
on
Macro Microcontroller 2
30m 23s logged
In this devlog, I updated the README.md contents as it was a little outdated due to the new firmware revision.
I also just realised I didn’t link the datasheet for my board in the README, so that is also one of the changes I made.
Additionally, I created a 404 page for my docs, and I will be making my second ship soon!
@nicholas1023
on
Macro Microcontroller 2
2h 25m 38s logged
In this devlog, I added new commands for my OS:
CALCULATE: Performs basic operations on 2 numbers. Usage: CALCULATE [Number] [+ - * / ^ root] [Number]
GPIO: Turns on a specified GPIO for 1 second. Usage: GPIO [LED# IO# BELL MOTOR]
VERSION: Shows the release version.REBOOT: Reboots the system. Usage: REBOOT -m [BASIC BOOTSEL]*
INFO: Displays device and memory information.UPTIME: Shows device uptime.I took quite a while to find out how to make the CALCULATE command work. Initially, 1/3 was returning 0. Turns out the problem was due to me using integers instead of doubles!
Here’s a demo video of the OS!
@nicholas1023
on
Macro Microcontroller 2
30m 21s logged
Since I added a new firmware, I have to update the downloads section of my site! It took me quite a while to organise my repo a little bit, as the firmware files were getting a little messier and releases getting more complicated as I have 2 firmware now!
Next, I’ll be working on the DOS, adding more commands to the system!
@nicholas1023
on
Macro Microcontroller 2
4h 6m 46s logged
Previously, I was asking myself: How can I make my device look more like an old PC?
When I was turning on an old desktop I have at home, I saw the BIOS screen due to CMOS errors, and this was where I got an inspiration for a new firmware update.
In this devlog, I redid the firmware, added a BIOS-like CLI, while still keeping the original BASIC interpreter as a fallback if no bootable “OS” was found. Here’s what it looks like:
_ _
| \/ | Macro Microcontroller BIOS Version 0.0.1.
|_\/_| Copyright (C) 2025-2026 Nicholas Lim.
Device: Macro Microcontroller 2 (RP2040 @ 125MHz)
Serial Number: ************
RAM Free: 254K OK
Serial Status: Connected
Press SW1 to enter Macro Microcontroller BASIC.
Press SW2 to enter BOOTSEL mode.
Booting system...
The UI was inspired by the old BIOS POST screens from the 1980s. As I wanted a retro feel to my microcontroller, I thought that a BIOS-like system would look nice to it!
Thanks for reading!
@nicholas1023
on
Macro Microcontroller 2
I’ve made Macro Microcontroller 2, a microcontroller development board and macropad with a custom BASIC interpreter firmware created in C from scratch! I’m proud of the PCB itself as I was surprised my board works well physically, as it was my first attempt creating one with a bare MCU chip on it! TO accompany the firmware and hardware, I created a documentation site to share more details as well!
Documentation: https://nicholas1023.github.io/macro-microcontroller-2/
@nicholas1023
on
Macro Microcontroller 2
3h 40m 21s logged
In this devlog, I made some changes to the firmware and released v0.0.3 that adds support for comments:
10 REM This is a comment that will be ignored!
20 PRINT "Hello world!"
I’ve also added a more detailed programming guide for my custom BASIC Interpreter.
I had some trouble soldering the keyboard switches on as it was moving everywhere. I’ve attempted applying tape, but it did not work as the temperature was too high.
I’ll be tidying up the repo and get ready to finally ship🚢 my project!
@nicholas1023
on
Macro Microcontroller 2
2h 55m 43s logged
In this devlog, I’ve added a new function to my custom BASIC interpreter for my development board, and finally sent my PCB for manufacturing!
It took me quite a while to write the random number function that the old BASIC interpreters used to have: RND. I did many rounds of trial and error to finally create a working code (the previous code was returning either nothing or throwing compiler errors due to data types):
printf("%f\n", (float)rand() / (float)RAND_MAX);
Here’s a sample program you could run that generates a random number, stores it in a variable and prints it:
10 let x = rnd
20 lsvar
30 print x
Now, I’ll be working on support for comments in my interpreter and wait for my parts to come. I can’t wait to assemble my macropad + dev board!
@nicholas1023
on
Macro Microcontroller 2
1h 15m 23s logged
Today, I changed the layout and content of the documentation website and made it responsive for mobile devices! I initially wanted to add a 3D viewer to display the .glb file for rendering, but it did not output the result I wanted. (The silkscreen was not appearing!) I’ll read up on more about it, and hopefully, I would be able to add the 3D model into my documentation!
@nicholas1023
on
Macro Microcontroller 2
2h 35m 8s logged
In this devlog, I improved the documentation of my project by creating a simple website to share specifications, schematics, and provide a direct link to download firmware and 3D print files. You may view it at https://nicholas1023.github.io/macro-microcontroller-2!
Next, I will be ordering the PCB and electronic components and finally solder them together!
@nicholas1023
on
Macro Microcontroller 2
3h 1m 13s logged
Today, I have completed the 3D case for Macro Microcontroller 2 and did some minor bug fixes for the BASIC Interpreter. I needed to reassign the GPIO pins from the first revision of the board.
Although the interpreter is currently still basic, it supports 4 BASIC statements and 4 custom statements for controls.
KEY statement for hardware GPIO control
@nicholas1023
on
Macro Microcontroller 2
2h 4m 14s logged
For the first-half, I added silkscreen text to the PCB for the IO components (GPIO Pins, Keyboard switches, LEDs…). Next, I moved on to designing the enclosure. It took a while for me to get used to using a new app to design it.
The screw holes were not appearing during the first few attempts, but it worked in the end when I placed it manually, instead of using the move function.
Creating the cutout for the USB connector took me about 15 mins as I needed to measure the length and clearance needed for a micro-USB plug and create another sketch before extruding it as a cutout.
Next, I’ll be continuing with the enclosure design, adding a cover with a keyboard plate, and finally moving on to the BASIC interpreter firmware for it!
@nicholas1023
on
Macro Microcontroller 2
2h 1m 39s logged
Did most of the routing for the MCU and macropad segment today, but I might need to do some rewiring for the flash memory as the trace length for SD0 and SD2 are very different (5.57 & 13.2 mm).
Next, I’ll be adding more silkscreen text, and maybe design an icon for my macropad + microcontroller board. I’ll also be creating a custom enclosure for my device!
@nicholas1023
on
Macro Microcontroller 2
2h 22m 57s logged
PRINT, LET and INPUT for the interpreter.Next, I will be focusing on the BASIC interpreter firmware, working on variable assignment and math operations and testing it on a real pico board! Also, I will be starting on the layout and BOM as I have completed the schematics!
