Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
Find a file
wangchengdong ed1cb6f9b8 sched/hrtimer: Add high-resolution timer support for NuttX
NuttX provides the wdog module to implement timers for the scheduler.
While it is lightweight and efficient, wdog only supports tick-level timers,
typically in milliseconds. Although the tick duration can be configured,
setting it to microsecond or nanosecond resolution is not practical.
Doing so may cause an interrupt storm, where the CPU is constantly
occupied handling tick interrupts.

To address this limitation, a new hrtimer module is introduced.
It coexists with the wdog module, providing both tick-level timers
for wdog and high-resolution timers (nanosecond-level) directly to users.

Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
2025-12-18 18:36:28 +08:00
.github mtd/at25ee: Use eeprom/spi_xx25xx internally 2025-12-17 19:03:54 +01:00
arch x86_64:fix syscall type mismatch 2025-12-18 06:31:43 +01:00
audio fs/file: unify prefix about file_xxx api, like file_open, file_ioctl 2025-06-12 18:12:42 +08:00
binfmt binfmt: Fix error handling in exec_module 2025-12-11 12:57:07 -05:00
boards sched/hrtimer: Add high-resolution timer support for NuttX 2025-12-18 18:36:28 +08:00
cmake cmake: Improve nuttx_generate_kconfig() 2025-12-02 02:45:36 +08:00
crypto crypto/hmac: Fix typo in function implementation names 2025-08-13 23:11:02 +08:00
Documentation mtd/at25ee: Use eeprom/spi_xx25xx internally 2025-12-17 19:03:54 +01:00
drivers virtio-blk:if in assert,don't wait semaphore 2025-12-18 18:21:55 +08:00
dummy build: add initial cmake build system 2023-07-08 13:50:48 +08:00
fs procfs/heapcheck:fix bug,aviod '\n' to 0 2025-12-18 15:37:30 +08:00
graphics sched/sleep: replace all Signal-based sleep implement to Scheduled sleep 2025-10-17 14:05:02 +08:00
include sched/hrtimer: Add high-resolution timer support for NuttX 2025-12-18 18:36:28 +08:00
libs libc: improve libc dependencies in case of LIBM_NONE 2025-12-14 17:57:27 -03:00
mm mm/: remove reference to non-existent readme 2025-10-11 17:07:51 -04:00
net tcp.h: add TCP_CORK definition 2025-12-18 15:38:17 +08:00
openamp sched/clock: remove return value of clock_systime_timespec() 2025-10-10 23:15:27 +08:00
pass1 Revert "build depend:Revert Make.dep intermediate ddc file" 2024-09-15 19:29:47 +08:00
sched sched/hrtimer: Add high-resolution timer support for NuttX 2025-12-18 18:36:28 +08:00
syscall sched/gettid: Move thread ID to TLS 2025-04-08 22:53:10 +08:00
tools tools/nxtagspkgsfetch.sh: Fetch tags packages for NuttX and Apps. 2025-12-17 08:12:44 -03:00
video Revert "build depend:Revert Make.dep intermediate ddc file" 2024-09-15 19:29:47 +08:00
wireless wireless/ieee802154/: remove the use of critical_section 2025-12-09 14:43:59 +08:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines usbhost: cdcacm exit wq after copy all received data 2025-12-14 10:37:53 -03:00
.codespellrc codespellrc: add ist to ignorelist 2025-10-14 17:42:01 +08:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore gitignore: add more vim swap files 2025-06-18 15:44:51 -04:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint
AUTHORS AUTHORS: add Michal Lenc 2025-12-03 08:46:33 -03:00
CMakeLists.txt cmake: Add support for ccache. 2025-12-05 11:46:30 +01:00
CONTRIBUTING.md style: fix spelling in code comments and strings 2025-05-23 10:48:41 +08:00
INVIOLABLES.md
Kconfig docs/config: Wrong term. 2025-10-23 16:46:31 +08:00
LICENSE style: fix spelling in code comments and strings 2025-05-23 10:48:41 +08:00
Makefile tools: migrate to SPDX identifier 2024-09-10 23:11:11 +08:00
NOTICE Remove the double blank line from source files 2022-02-20 20:10:14 +01:00
README.md Gathering community recommendations 2023-10-28 13:55:56 +08:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

POSIX Badge License Issues Tracking Badge Contributors GitHub Build Badge Documentation Badge

Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).

For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.

Getting Started

First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.

Documentation

You can find the current NuttX documentation on the Documentation Page.

Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.

The old NuttX documentation is still available in the Apache wiki.

Supported Boards

NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.

Contributing

If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.

License

The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.