How to install the systick-timer crate // Lib.rs

Adding `systick_timer` library as a dependency

Run this command in a terminal, in your project's directory:

cargo add systick-timer

To add it manually, edit your project's Cargo.toml file and add to the [dependencies] section:

systick-timer = "0.2.2"

The systick_timer library will be automatically available globally. Read the systick_timer library documentation.

Back to the crate overview.

Readme

64-bit SysTick timer for Cortex-M0

Implements a 64-bit SysTick based timer, that tracks overflows and provides as single monotonic 64-bit value at the desired resolution. The only dependencies are cortex-m and cortex-m-rt crates.

Optionally wraps this in an embassy-time-driver.

⚠️ Critical Design Constraint

The SysTick ISR must not be starved for more than one wrap period.

This timer implementation is designed to handle exactly one missed SysTick wrap through its PendST bit detection mechanism. If the SysTick ISR is delayed by higher-priority interrupts for more than one complete wrap period, monotonic time violations will occur.

Reminders:

Keep the SysTick ISR at higher or equal priority relative to application interrupts
Ensure critical sections in higher-priority ISRs are brief, e.g. well shorter than SysTick reload interval

The implementation itself is non-locking and does not use critical sections.

Examples included for QEMU Cortex-M0.

To run the demos with QEMU:

cargo runq --example basic_time

Embassy version:

cargo runq --example embassy_time

Testing

To run the tests, run without default features:

cargo test --no-default-features

Todo:

Add a constant-execution time option to now(). This would trade off slower average access to deterministic, worst-case execution.

Adding systick_timer library as a dependency

Adding `systick_timer` library as a dependency