80 lines
2.7 KiB
ReStructuredText
80 lines
2.7 KiB
ReStructuredText
.. _introducing_zephyr:
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Introducing Zephyr
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##################
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The Zephyr OS is based on a small-footprint kernel designed for use on
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resource-constrained systems: from simple embedded environmental sensors and LED
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wearables to sophisticated smart watches and IoT wireless gateways.
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The Zephyr kernel supports multiple architectures, including ARM Cortex-M, Intel
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x86, ARC, NIOS II, Tensilica Xtensa, and RISC-V. The full list of supported
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boards can be found :ref:`here <boards>`.
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Licensing
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*********
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Zephyr uses the `Apache 2.0 license`_ (as found in the LICENSE file in the
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project's `GitHub repo`_). There are some
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imported or reused components of the Zephyr project that use other licensing,
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as described in :ref:`Zephyr_Licensing`.
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.. _Apache 2.0 license:
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https://github.com/zephyrproject-rtos/zephyr/blob/master/LICENSE
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.. _GitHub repo: https://github.com/zephyrproject-rtos/zephyr
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Distinguishing Features
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***********************
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The Zephyr kernel offers a number of features that distinguish it from other
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small-footprint OSes:
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#. **Single address-space**. Combines application-specific code
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with a custom kernel to create a monolithic image that gets loaded
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and executed on a system's hardware. Both the application code and
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kernel code execute in a single shared address space.
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#. **Highly configurable**. Allows an application to incorporate *only*
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the capabilities it needs as it needs them, and to specify their
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quantity and size.
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#. **Compile-time resource definition**. Allows system resources
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to be defined at compile-time, which reduces code size and
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increases performance.
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#. **Minimal error checking**. Provides minimal runtime error checking
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to reduce code size and increase performance. An optional error-checking
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infrastructure is provided to assist in debugging during application
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development.
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#. **Extensive suite of services**. Offers a number of familiar services
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for development:
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* *Multi-threading Services* for priority-based, non-preemptive and
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preemptive threads with optional round robin time-slicing.
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* *Interrupt Services* for compile-time registration of interrupt handlers.
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* *Memory Allocation Services* for dynamic allocation and freeing of
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fixed-size or variable-size memory blocks.
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* *Inter-thread Synchronization Services* for binary semaphores,
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counting semaphores, and mutex semaphores.
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* *Inter-thread Data Passing Services* for basic message queues, enhanced
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message queues, and byte streams.
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* *Power Management Services* such as tickless idle and an advanced idling
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infrastructure.
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.. include:: ../../README.rst
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:start-after: start_include_here
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Fundamental Terms and Concepts
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******************************
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See :ref:`glossary`
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