The blog post details the author's experience porting Rust to the RockPro64 (RP2350) single-board computer. They successfully brought up a minimal Rust environment, including core libraries, allowing basic "Hello, world!" functionality and interaction with GPIO pins. The process involved building a custom cross-compilation toolchain based on a pre-built Debian image, navigating architectural differences like the lack of an MMU, and implementing necessary drivers. While challenging, this achievement lays the groundwork for more complex Rust development on the RP2350, potentially opening doors for embedded systems applications.
James Munns, author of the blog "thejpster," details his experience porting Rust to the RP2040 microcontroller's successor, the RP2350. He begins by highlighting the significant architectural differences between the two chips. While the RP2040 utilized a dual-core ARM Cortex-M0+ architecture, the RP2350 boasts a single, more powerful ARM Cortex-M33 core. This shift necessitates a re-evaluation and adaptation of existing Rust development tools and libraries designed for the RP2040.
Munns then dives into the specific challenges encountered during the porting process. A key hurdle involved adapting the rp2040-hal hardware abstraction layer (HAL), a crucial component for interacting with the microcontroller's peripherals. Due to the architectural differences, a direct port was impossible. He explains the intricate process of modifying the HAL, including working with SVD files (System View Description) which describe the peripherals of the RP2350. This required careful examination and adaptation of register definitions and peripheral configurations to match the new chip’s specifications.
He recounts the steps taken to configure the chip's clock system, a fundamental aspect of microcontroller operation. This included setting up the appropriate clock frequencies for various peripherals and ensuring system stability. Furthermore, he describes configuring the UART (Universal Asynchronous Receiver/Transmitter) for serial communication, a crucial step for debugging and interacting with the microcontroller. This involved setting baud rates and other communication parameters specific to the RP2350’s UART implementation.
A significant accomplishment highlighted by Munns is successfully blinking an LED, a canonical introductory exercise in embedded systems programming. This signifies a foundational level of control over the RP2350 using Rust. He elucidates the process of configuring the GPIO (General Purpose Input/Output) pins to control the LED, demonstrating basic peripheral interaction.
Finally, he concludes by acknowledging that the port is still in its nascent stages. While basic functionality, such as LED control and UART communication, is operational, significant work remains to bring the Rust ecosystem for the RP2350 to parity with that of the RP2040. He emphasizes the need for further development and community involvement in building out a robust and feature-rich HAL and supporting libraries. He expresses optimism about the future of Rust development on the RP2350, foreseeing its potential to unlock the chip’s enhanced capabilities for a wide range of embedded applications.
Summary of Comments ( 34 )
https://news.ycombinator.com/item?id=43378571
HN commenters generally express enthusiasm for Rust's increasing viability on embedded platforms, particularly the RP2040. Several users discuss the benefits of Rust's memory safety and performance in this context, comparing it favorably to C/C++. Some point out the challenges of working with Rust on resource-constrained devices, like managing memory allocation and dealing with abstractions that can add overhead. A few commenters also mention specific crates like
rp-picoandembassy, highlighting their usefulness for embedded Rust development on the RP2040. There's also discussion around build times, tooling, and the learning curve associated with Rust, with some suggesting that the ecosystem is still maturing but rapidly improving. Finally, some users share their own experiences and projects using Rust on embedded systems.The Hacker News post "Rust on the RP2350 (2024)" has generated a modest discussion with a few interesting points.
Several commenters focus on the practicalities and limitations of using Rust on a microcontroller like the RP2350. One commenter questions the practicality of using Rust given the limited flash memory available on these devices, highlighting that even a "hello world" program in Rust can consume a significant portion of the available space. This concern is echoed by another user who expresses skepticism about fitting more complex logic within the microcontroller's constraints while using Rust. The original poster (OP) responds to this concern, explaining their usage of
min-sized-rust, a project aimed at reducing the binary size of Rust programs, enabling them to fit within the limited flash memory.There's also a discussion around the choice of programming language for embedded systems. One commenter mentions their successful experience using C with the RP2040 and inquires about any advantages offered by Rust in this context. The OP clarifies they aren't advocating for Rust as the sole solution but are exploring it due to its memory safety features, which they value for writing more reliable code.
One commenter shifts the discussion towards the build process, expressing frustration with CMake and highlighting their preference for the Meson build system due to its perceived ease of use, especially for cross-compilation.
Finally, a brief exchange touches upon the challenges of debugging Rust code on embedded systems. One user recommends using probe-run, while acknowledging its occasional instability.
The discussion, while not extensive, provides valuable insights into the challenges and tradeoffs involved in using Rust for embedded development on resource-constrained microcontrollers like the RP2350. The comments cover topics like binary size, memory safety, build systems, and debugging, reflecting practical considerations faced by developers in this space.