From 6dc46ce1c6eb54e453c7dfb46eda44a596648329 Mon Sep 17 00:00:00 2001 From: Per Lindgren Date: Wed, 1 Feb 2023 11:50:08 +0100 Subject: [PATCH] Monotonic book --- book/en/src/by-example/tips_monotonic_impl.md | 26 +++++++------------ 1 file changed, 10 insertions(+), 16 deletions(-) diff --git a/book/en/src/by-example/tips_monotonic_impl.md b/book/en/src/by-example/tips_monotonic_impl.md index 7c3449b2b3..57b0a01c8e 100644 --- a/book/en/src/by-example/tips_monotonic_impl.md +++ b/book/en/src/by-example/tips_monotonic_impl.md @@ -1,35 +1,29 @@ # Implementing a `Monotonic` timer for scheduling -The framework is flexible because it can use any timer which has compare-match and optionally -supporting overflow interrupts for scheduling. -The single requirement to make a timer usable with RTIC is implementing the -[`rtic_monotonic::Monotonic`] trait. +The framework is flexible because it can use any timer which has compare-match and optionally supporting overflow interrupts for scheduling. The single requirement to make a timer usable with RTIC is implementing the [`rtic-time::Monotonic`] trait. -Implementing time counting that supports large time spans is generally **difficult**, in RTIC 0.5 -implementing time handling was a common problem. -Moreover, the relation between time and timers used for scheduling was difficult to understand. - -For RTIC 1.0 we instead assume the user has a time library, e.g. [`fugit`] or [`embedded_time`], -as the basis for all time-based operations when implementing `Monotonic`. -These libraries make it much easier to correctly implement the `Monotonic` trait, allowing the use of +For RTIC 1.0 and 2.0 we instead assume the user has a time library, e.g. [`fugit`] or [`embedded_time`], as the basis for all time-based operations when implementing `Monotonic`. These libraries make it much easier to correctly implement the `Monotonic` trait, allowing the use of almost any timer in the system for scheduling. -The trait documents the requirements for each method, -and for inspiration here is a list of `Monotonic` implementations: +The trait documents the requirements for each method, and for inspiration +there is a reference implementation based on the `SysTick` timer available on all ARM Cortex M MCUs. + +- [`Systick based`], runs at a fixed interrupt (tick) rate - with some overhead but simple and provides support for large time spans + +Here is a list of `Monotonic` implementations for RTIC 1.0: - [`STM32F411 series`], implemented for the 32-bit timers - [`Nordic nRF52 series Timer`], implemented for the 32-bit timers - [`Nordic nRF52 series RTC`], implemented for the RTCs -- [`Systick based`], runs at a fixed interrupt (tick) rate - with some overhead but simple and with support for large time spans - [`DWT and Systick based`], a more efficient (tickless) implementation - requires both `SysTick` and `DWT`, supports both high resolution and large time spans If you know of more implementations feel free to add them to this list. -[`rtic_monotonic::Monotonic`]: https://docs.rs/rtic-monotonic/ +[`rtic_time::Monotonic`]: https://docs.rs/rtic_time/ [`fugit`]: https://docs.rs/fugit/ [`embedded_time`]: https://docs.rs/embedded_time/ [`STM32F411 series`]: https://github.com/kalkyl/f411-rtic/blob/a696fce7d6d19fda2356c37642c4d53547982cca/src/mono.rs [`Nordic nRF52 series Timer`]: https://github.com/kalkyl/nrf-play/blob/47f4410d4e39374c18ff58dc17c25159085fb526/src/mono.rs [`Nordic nRF52 series RTC`]: https://gist.github.com/korken89/fe94a475726414dd1bce031c76adc3dd -[`Systick based`]: https://github.com/rtic-rs/systick-monotonic +[`Systick based`]: https://github.com/rtic-monotonics [`DWT and Systick based`]: https://github.com/rtic-rs/dwt-systick-monotonic