I wanted to share my experience experimenting with Rust on the Adafruit RP2040 Feather ThinkInk board, specifically using a bare E-Paper display.

Hardware:

• Adafruit RP2040 Feather ThinkInk (https://www.adafruit.com/product/5727)
• Bare EPD display (JD79661 chipset): {https://www.adafruit.com/product/6373)

Background

I went through all the official tutorials for the ThinkInk Feather: https://learn.adafruit.com/adafruit-rp2040-feather-thinkink

The provided examples are excellent, but they currently focus on CircuitPython and Arduino. Adafruit already provides solid drivers for the JD79661 chipset, and the display is also well supported in the Arduino ecosystem via the GxEPD2 library: https://github.com/ZinggJM/GxEPD2

This made me curious: can I do the same thing in Rust?

Rust on RP2040

The RP2040 has very good Rust support thanks to the rp-rs ecosystem. A great starting point is the RP2040 project template: https://github.com/rp-rs/rp2040-project-template

There is also an existing HAL board definition for the Adafruit Feather RP2040 here: https://github.com/rp-rs/rp-hal-boards/tree/main/boards/adafruit-feather-rp2040

While it’s not an exact match for the ThinkInk Feather, it’s close enough to serve as a solid base, with only minor adjustments needed.

Driver work

At the moment, there is no native Rust driver for the JD79661 E-Paper controller. To move forward, I implemented a custom Rust driver, based directly on the source code from Adafruit’s CircuitPython and Arduino implementations.

Once the low-level driver was in place, everything integrated nicely with the Embedded Graphics framework. Rendering text and images worked as expected.

As a proof of concept, I was able to:

• Convert a JPG image to BMP
• Render and display it correctly on the E-Paper display

Results & Code

All of my experiments and findings are documented here: https://github.com/melastmohican/adafruit-feather-thinkink-discovery

The repository includes:

• Project setup for Rust on the ThinkInk Feather
• A custom JD79661 driver
• Examples using Embedded Graphics
• Notes on differences between the standard Feather RP2040 and the ThinkInk variant

Closing thoughts

Overall, Rust works very well on the RP2040, and bringing up an E-Paper display was quite feasible even without an existing driver. Hopefully this helps others who want to explore Rust + E-Paper + Adafruit hardware.