RT Features

RT is the advanced kernel of ChibiOS, it is designed to be a state of the art RTOS for deeply embedded applications. The design guidelines have been:

  • No compromises in performance, it has to be the fastest performing RTOS available.
  • Scalable from 8 bits architectures upward.
  • Functionally complete API. All common RTOS features have to be supported.
  • Fully Static Architecture.
  • Clean and elegant code base.
  • Predictable and Deterministic.
  • Small Size.
  • Fully compliant with HAL OSAL.
  • MISRA 2012 compliance.

See the RT vs NIL article for a full list of the RT features.


In addition to the common RTOS features RT implements a set of unique features that make it one of the most advanced RTOS available:

Feature Description
Real Tick-less Mode The kernel does not require a system tick, interrupts are generated only at the scheduled time. This is optimal for implementing advanced power management modes.
High Resolution Time The time resolution can reach sub-microseconds values. It is possible to use very small delays in tasks.
Full Thread Paradigm Not just “tasks”, the threads paradigm is fully implemented: Create, Exit, Join operations are available.
Cycle-Accurate Statistics Critical zones, ISRs, tasks execution times are measured with a clock-accurate resolution, best/last/worst execution time is reported for all critical code paths.
System State Checker The API call protocol is checked vs the current system state, invalid calls are detected and reported. This resolves at development time one of the most insidious errors in RTOS usage. Potentially saving, by design, from intermittent and hard to debug problems.
Safety Features The RTOS implements a number of safety-related features like: Runtime integrity check API, stacks overflow detection, static design, RTOS global data structures encapsulation.
RT Performance

Fastest RTOS? Reasons for this statement and performance data.

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Tick-Less Mode

Both RT and NIL kernels support an advanced tick-less mode that allows to implement advanced power management.

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High Resolution Time

One of the most advanced features of the RT kernel is the ability to handle software timers, delays and time-outs with a very high resolution.

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The RT State Checker

One important debug feature in the RT kernel is the System State Checkers. This debug option can save countless hours lost in hunting intermittent problems.

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