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Andrzej Kuros e03d5d4c6d nrf53: RTC pretick allows user channels and require just one CC
The nrf53 pretick can be used with non-zero
`NRF_RTC_TIMER_USER_CHAN_COUNT` Kconfig option.

The nrf53 pretick requires just one RTC1 CC channel.

The nrf53 pretick handles also RTC1 and RTC0 both CCs and OVERFLOW
events by examination of events scheduled on them. The pretick is set
based on number of ticks to the closest event scheduled that can trigger
an interrupt.

Because the operation in `z_arm_on_enter_cpu_idle` hook would
take too much time with interrupts disabled, the
`z_arm_on_enter_cpu_idle_prepare` hook enabled by Kconfig option
`ARM_ON_ENTER_CPU_IDLE_PREPARE_HOOK` is used. It performs RTC0 and RTC1
examination, and sets pretick without interrupts being blocked.

The LDREX/STREX are leveraged to detect if exception took place
between start of `z_arm_on_enter_cpu_idle_prepare` and
`z_arm_on_enter_cpu_idle`. If exception has not been taken, the pretick
calculation can be trusted because source data could not changed and
too much time could not pass. Otherwise the sleep attempt is disallowed,
the idle will loop again and try later.

Prompt for `SOC_NRF53_RTC_PRETICK` Kconfig option allows to control
this option by an user and turn the feature off if necessary.

Signed-off-by: Andrzej Kuroś <andrzej.kuros@nordicsemi.no>
2023-09-30 18:48:19 +02:00
.github actions: greet: Update the PR greeting text 2023-09-27 09:29:41 +01:00
arch arch: arm: aarch32: Introduce z_arm_on_enter_cpu_idle_prepare() hook 2023-09-30 18:48:19 +02:00
boards doc: boards: Link to the board porting guide 2023-09-29 16:29:49 +02:00
cmake cmake: warn the user that the toolchain cache hides errors 2023-09-22 13:42:21 +02:00
doc doc: Add object core documentation 2023-09-30 08:04:14 +03:00
drivers nrf53: RTC pretick allows user channels and require just one CC 2023-09-30 18:48:19 +02:00
dts counter: nxp_s32_sys_timer: use clock control APIs 2023-09-29 16:29:31 +02:00
include/zephyr arch: arm: aarch32: Introduce z_arm_on_enter_cpu_idle_prepare() hook 2023-09-30 18:48:19 +02:00
kernel kernel: remove unused z_init_thread_base from kernel.h 2023-09-30 18:43:28 +02:00
lib kernel: Integrate object core statistics 2023-09-30 08:04:14 +03:00
misc misc: generated: update configs.c template with <zephyr/...> prefix 2022-05-09 12:45:29 -04:00
modules net: pkt: time: introduce ns timestamp helper 2023-09-29 16:27:15 +02:00
samples llext: Shell loader sample 2023-09-29 20:50:38 -04:00
scripts scripts: runners: rework RunnerCaps implementation 2023-09-29 16:30:07 +02:00
share sysbuild: Do not exclude images from domains.yaml 2023-09-27 17:49:12 +02:00
snippets snippets: xen_dom0: add support for Renesas R-Car Gen3 boards 2023-09-15 11:15:00 +01:00
soc nrf53: RTC pretick allows user channels and require just one CC 2023-09-30 18:48:19 +02:00
submanifests
subsys mgmt/MCUmgr/mgmt: Support for finding registered command groups 2023-09-30 18:48:06 +02:00
tests modem: modem_pipe: Avoid inconsequential open/close calls 2023-09-30 18:47:48 +02:00
.checkpatch.conf checkpatch: Remove ext/ from excludes 2022-11-30 12:06:55 -05:00
.clang-format clang-format: flag *_SECTION_FOREACH as for loop 2023-05-26 11:04:54 -05:00
.codecov.yml yamllint: fix all yamllint comments errors 2023-01-04 01:16:45 +09:00
.editorconfig editorconfig: Improve verbosity 2022-04-28 08:55:39 -04:00
.gitattributes gitattributes: consider SVG files generated 2021-10-14 12:42:44 -04:00
.gitignore scripts: compliance: add a check for missing west area maintainer enties 2023-09-14 08:13:57 -07:00
.gitlint .gitlint: de-duplicate defaults with zephyr_commit_rules.py 2023-09-21 09:29:24 +02:00
.mailmap mailmap: sort alphabetically 2023-05-15 13:23:32 -04:00
.yamllint scripts: compliance: add support for YAMLLint 2023-01-04 17:29:23 +01:00
CMakeLists.txt cmake: skip build time priority checking with armclang 2023-09-20 20:24:46 +01:00
CODE_OF_CONDUCT.md
CODEOWNERS MAINTAINERS: Update maintainers/codeowners for conn_mgr docs 2023-09-28 15:11:14 +02:00
CONTRIBUTING.rst
Kconfig
Kconfig.zephyr cmake: skip build time priority checking with armclang 2023-09-20 20:24:46 +01:00
LICENSE
MAINTAINERS.yml llext: Maintainers file 2023-09-29 20:50:38 -04:00
README.rst readme: Add support for light/dark modes in the logo 2022-11-18 08:58:59 +01:00
VERSION release: bump main to v3.4.99 2023-06-16 13:29:34 -04:00
version.h.in kernel: banner: Allow for customising version 2023-08-21 10:09:46 +02:00
west.yml west.yml: Pull in latest percepio updates 2023-09-30 08:04:14 +03:00
zephyr-env.cmd
zephyr-env.sh everywhere: fix typos 2022-03-18 13:24:08 -04:00

.. raw:: html

   <a href="https://www.zephyrproject.org">
     <p align="center">
       <picture>
         <source media="(prefers-color-scheme: dark)" srcset="doc/_static/images/logo-readme-dark.svg">
         <source media="(prefers-color-scheme: light)" srcset="doc/_static/images/logo-readme-light.svg">
         <img src="doc/_static/images/logo-readme-light.svg">
       </picture>
     </p>
   </a>

   <a href="https://bestpractices.coreinfrastructure.org/projects/74"><img
   src="https://bestpractices.coreinfrastructure.org/projects/74/badge"></a>
   <a
   href="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml?query=branch%3Amain">
   <img
   src="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml/badge.svg?event=push"></a>


The Zephyr Project is a scalable real-time operating system (RTOS) supporting
multiple hardware architectures, optimized for resource constrained devices,
and built with security in mind.

The Zephyr OS is based on a small-footprint kernel designed for use on
resource-constrained systems: from simple embedded environmental sensors and
LED wearables to sophisticated smart watches and IoT wireless gateways.

The Zephyr kernel supports multiple architectures, including ARM (Cortex-A,
Cortex-R, Cortex-M), Intel x86, ARC, Nios II, Tensilica Xtensa, and RISC-V,
SPARC, MIPS, and a large number of `supported boards`_.

.. below included in doc/introduction/introduction.rst


Getting Started
***************

Welcome to Zephyr! See the `Introduction to Zephyr`_ for a high-level overview,
and the documentation's `Getting Started Guide`_ to start developing.

.. start_include_here

Community Support
*****************

Community support is provided via mailing lists and Discord; see the Resources
below for details.

.. _project-resources:

Resources
*********

Here's a quick summary of resources to help you find your way around:

* **Help**: `Asking for Help Tips`_
* **Documentation**: http://docs.zephyrproject.org (`Getting Started Guide`_)
* **Source Code**: https://github.com/zephyrproject-rtos/zephyr is the main
  repository; https://elixir.bootlin.com/zephyr/latest/source contains a
  searchable index
* **Releases**: https://github.com/zephyrproject-rtos/zephyr/releases
* **Samples and example code**: see `Sample and Demo Code Examples`_
* **Mailing Lists**: users@lists.zephyrproject.org and
  devel@lists.zephyrproject.org are the main user and developer mailing lists,
  respectively. You can join the developer's list and search its archives at
  `Zephyr Development mailing list`_. The other `Zephyr mailing list
  subgroups`_ have their own archives and sign-up pages.
* **Nightly CI Build Status**: https://lists.zephyrproject.org/g/builds
  The builds@lists.zephyrproject.org mailing list archives the CI nightly build results.
* **Chat**: Real-time chat happens in Zephyr's Discord Server. Use
  this `Discord Invite`_ to register.
* **Contributing**: see the `Contribution Guide`_
* **Wiki**: `Zephyr GitHub wiki`_
* **Issues**: https://github.com/zephyrproject-rtos/zephyr/issues
* **Security Issues**: Email vulnerabilities@zephyrproject.org to report
  security issues; also see our `Security`_ documentation. Security issues are
  tracked separately at https://zephyrprojectsec.atlassian.net.
* **Zephyr Project Website**: https://zephyrproject.org

.. _Discord Invite: https://chat.zephyrproject.org
.. _supported boards: http://docs.zephyrproject.org/latest/boards/index.html
.. _Zephyr Documentation: http://docs.zephyrproject.org
.. _Introduction to Zephyr: http://docs.zephyrproject.org/latest/introduction/index.html
.. _Getting Started Guide: http://docs.zephyrproject.org/latest/develop/getting_started/index.html
.. _Contribution Guide: http://docs.zephyrproject.org/latest/contribute/index.html
.. _Zephyr GitHub wiki: https://github.com/zephyrproject-rtos/zephyr/wiki
.. _Zephyr Development mailing list: https://lists.zephyrproject.org/g/devel
.. _Zephyr mailing list subgroups: https://lists.zephyrproject.org/g/main/subgroups
.. _Sample and Demo Code Examples: http://docs.zephyrproject.org/latest/samples/index.html
.. _Security: http://docs.zephyrproject.org/latest/security/index.html
.. _Asking for Help Tips: https://docs.zephyrproject.org/latest/develop/getting_started/index.html#asking-for-help