Pre-Emptive Multi-Tasking on Arm Cortex-M
7 hours ago
- #Rust
- #RTOS
- #Embedded
- The article discusses writing a pre-emptive multi-tasking RTOS (Real-Time Operating System) for Arm Cortex-M processors using Rust.
- Background: The author writes embedded software in Rust, including for safety-critical systems, often transitioning from C-based RTOSes.
- C-language RTOSes: Lists several RTOS options like FreeRTOS, ThreadX, Zephyr, etc., highlighting their variability in features, licensing, and safety-critical ratings.
- Rust-language RTOSes: Mentions RTOSes written in Rust, such as embassy and RTIC, noting their different approaches to task handling.
- RTOS Definition: Explains that an RTOS provides real-time guarantees, allowing tasks to run with predictable timing, unlike general-purpose OSes like Windows.
- Arm Cortex-M Features: Details how Cortex-M processors facilitate RTOS development with features like automatic register saving, SysTick timer, and PendSV exception for task switching.
- Writing an RTOS in Rust: Describes the process of setting up task stacks, using PendSV for context switching, and managing task states.
- Example Implementation: Provides a Rust code example demonstrating task creation, stack management, and scheduler initialization.
- Conclusions: Summarizes that writing an RTOS in Rust for Cortex-M is feasible with about 300 lines of code, leveraging hardware features effectively without needing C.