MicroPython Drivers for PicoCalc

‼️ Updates

• Multithreading Example Present in branch multithreading, not updated to latest yet, but provides an example implementation.

• Eigenmath is now included, bringing some actual calculator functionality back to the PicoCalc. It is available for import in both versions, however if a lite version is wanted (would save about 250kb) I could compile them.

  Thank @zerodante for his work on it!

• Install instructions simplified! Install instructions now allow just an upload of the full /libs folder, and have been simplified to avoid confusion.

🏗️ Build Instructions

Folder structure:

|
|- micropython                     # Clone the MicroPython repo here
|   |- ports
|      |- rp2
|         |- modules               # Place all py files from pico_files/modules/ if you want them added internally
|
|- PicoCalc-micropython            # Driver modules
|   |- picocalcdisplay
|   |- vtterminal
|   |- eigenmath_micropython
|
|- Any additional modules (e.g., ulab, etc.)

First initalize the repository with:

cd PicoCalc-micropython
git submodule update --init --recursive

Prepare for build by copying all files from PicoCalc-micropython/build_files into /micropython/ports/rp2/modules/

Then Build MicroPython as usual, while including user modules:

cd ../micropython/ports/rp2
git submodule update --init --recursive
mkdir build && cd build
cmake .. \
-DUSER_C_MODULES="location/of/PicoCalc-micropython/picocalcdisplay/micropython.cmake; \
location/of/PicoCalc-micropython/vtterminal/micropython.cmake; \
location/of/micropython-cppmem/micropython.cmake; \
location/of/PicoCalc-micropython/eigenmath_micropython/micropython.cmake" \
-DMICROPY_BOARD=TARGET_BOARD

Supported TARGET_BOARD values:

• RPI_PICO
• RPI_PICO2
• RPI_PICO2_W

IF USING HOMEBREW DEFINITIONS:

• PIMORONI_PICO2_PLUS
• PIMORONI_PICO2_PLUS_W

To use "homebrew" board definitions, copy them to you /micropython/ports/rp2/boards folder (Other boards are untested.)

⚠️ NOTE: The homebrew board definitions are NOT the official Pimoroni board definitions, they are the basic Pico2 definitions tailored to work with the Pimoroni board via enabling PSRAM and the WiFi stack as nessecary. They are tested and work with the PicoCalc, but may lack some functionality like PIO.

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Installation

• Flash the compiled .uf2 to your Pico as usual.
• Place only main.py,root.py from pico_files/root/ in the pico root directory.
• Upload whole /lib folder to the root directory as it contains nessecary libraries. Note: I may also create uf2 with lib folder frozen in automatically, with no need to copy, however I do not really like this as it removes the ability to easily tweak them on device. Request it if you want it

Using Thonny is the easiest method for file transfer and interaction.

If the flash nuke is needed, flash as normal, however DO NOT UNPLUG until the on-board light flashes to indicate it is done.

Features

✅ Keyboard Driver

Fully functional and tested. Works seamlessly with vt100 terminal emulator.

✅ ILI9488 Display Driver (C module + Python interface)

• C module supports high-speed 1/2/4/8-bit LUT drawing and 16-bit 565RGB.
• Python wrapper uses framebuf interface and handles display swapping.
• Display updates now run on core1 for a smoother REPL experience.

✅ screen capture

• Using ctrl + u to capture screen buffer into your sd card. currently only at the root of the sd card The Data is in raw type. For default 16 color framebuff copy, it is 50kB each. Left pixel in high 4 bit. Standard vt 100 16 color map may use to rebuild the image. I will upload a python script to convert it.

✅ Speaker Driver

Enabled by LaikaSpaceDawg!

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Usage Notes

⚠️ Working with WiFi on PicoW/2W

Due to the WiFi chip connecting to the RP2040/2350 via SPI1, which is shared with LCD, it is necessary to stop the auto refresh function first via the function: pc_terminal.stopRefresh(), after wifi finish its work, use pc_terminal.recoverRefresh() to recover the LCD refreshing.

Internal code editor

You can launch the built-in Python code editor by calling:

edit("abc.py")

Editor is based on robert-hh/Micropython-Editor
Now with keyword highlighting support.

run examples

Copy examples folder under pico_files to your pico module root. Run it via command

run('/examples/rotation.py')

➕ ➖ ✖️ ➗ Eigenmath

Eigenmath is initalized early during system startup because it requires a contiguous 300kB block from the MicroPython heap. If we delay this allocation until later stages of the boot process, heap fragmentation may prevent us from obtaining such a large continuous memory region.

#import eigenmath #not necessary, init in the boot
#em = eigenmath.EigenMath(300*1024) #the internal heap size, eigenmath needs A LOT OF RAM. It will be released after you delete the em instance
em.status() #show current resource status
em.run("d(sin(x),x)") #do math calculation, check the eigenmath manual for more details
em.reset() #reset the internal sources

#if you don't need it anymore
del builtins.em #del the eigenmath from root
gc.collect()

💻 Display Functionality

Accessing the Display

The screen is exposed via picocalc.display, which is an instance of the PicoDisplay class (a subclass of framebuf). You can use all standard framebuf methods to draw on it.

VT100 Emulator Mode

• Runs in 4-bit color (16 colors) mode to save limited RAM (≈50 KB).
• Uses an internal color lookup table (LUT) to map logical VT100 colors to the actual RGB565 values sent to the panel.

Color Lookup Table (LUT)

• Reset to the default VT100 palette

  picocalc.display.resetLUT()

• Switch to a predefined LUT

  picocalc.display.switchPredefinedLUT("name")

  Available presets: "vt100", "pico8" (more coming soon).

Inspecting and Modifying the LUT

• Get the current LUT

  lut = picocalc.display.getLUT()

  Returns a 256-entry, big-endian 16-bit array you can read from or write to directly.

• Note on color format

  • The display expects RGB565 values.
  • Because of SPI byte‐order, you must swap high/low bytes when writing back to the LUT.

• Set a custom LUT

  picocalc.display.setLUT(custom_array)

  Accepts up to 256 16-bit elements to override the existing table.

Example usage: see examples/mandelbrot.py.

Core Usage & Refresh Modes

By default:

• Core 0 runs the MicroPython VM.
• Core 1 continuously performs color conversion and refreshes the screen in the background.

You can switch to passive refresh mode: Please refer the /examples/refresh.py for more details.

# stop auto refresh
picocalc.display.stopRefresh()
# recover auto refresh
picocalc.display.recoverRefresh()
# manually update the screen by core 0, default is done by core 1, so you could use all core 0 for other logic
picocalc.display.show(0)
# wait the manual refresh function release the vram. If you use the manual refuresh function
picocalc.display.isScreenUpdateDone()

• In passive mode, the screen only updates when you explicitly call:

  picocalc.display.show(core=1)

• The show() method takes a core argument (0 or 1) to choose which core handles color conversion and DMA ping‐pong buffer setup.

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Credits

• robert-hh/Micropython-Editor
• ht-deko/vt100_stm32
• sdcard.py is from the official MicroPython repository: micropython-lib/sdcard.py
• flash_nuke.uf2 is from the Raspberry Pi Documentation: Resetting Flash Memory