Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
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Tiago Medicci Serrano 96d71ea565 xtensa/esp32s3: Re-apply WDT prescaler and timeout at start.
With the BOARD_LATE_INITIALIZE flow, board_late_initialize() runs
on a kernel thread and sets the MWDT0 prescaler. However, after it
returns, the init task (NSH) is spawned and lib_cxx_initialize()
invokes constructor functions, including
enable_timer_group0_for_calibration() from esp-hal-3rdparty which
calls timg_ll_reset_register(0), resetting all Timer Group 0
registers (including the WDT prescaler) back to their defaults.

Re-apply the prescaler, timeout, and feed the WDT counter in
wdt_lh_start() just before enabling the timer. This ensures
correct WDT configuration regardless of any intermediate register
resets by external code.

Signed-off-by: Tiago Medicci Serrano <tiago.medicci@espressif.com>
2026-05-27 09:36:43 +08:00
.github build(deps): bump docker/login-action from 4.0.0 to 4.2.0 2026-05-25 15:56:41 -04:00
arch xtensa/esp32s3: Re-apply WDT prescaler and timeout at start. 2026-05-27 09:36:43 +08:00
audio include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
binfmt include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
boards boards/risc-v/esp32p4: Add LP Mailbox board support 2026-05-26 10:03:43 +08:00
cmake cmake: nuttx_create_symlink: Remove warning for CMP0205 2026-05-26 15:11:35 -03:00
crypto !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
Documentation Documentation: Document taskset command. 2026-05-26 23:15:36 +08:00
drivers !drivers: separate pulse count feature from PWM driver 2026-05-25 14:33:11 +02:00
dummy build: add initial cmake build system 2023-07-08 13:50:48 +08:00
fs !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
graphics include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
include !boards/boardctl: Remove BOARDIOC_INIT 2026-05-26 09:57:29 +08:00
libs arch/tricore: Full implementation of setjmp and longjmp. 2026-05-22 00:38:02 +08:00
mm !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
net !sys/types.h: change time_t and clock_t to int64_t to align with other OSes 2026-05-19 16:21:28 +08:00
openamp openamp: fix CMake dcache option 2026-05-10 15:03:24 +02:00
pass1 Makefile: Remove make depend files by make distclean 2026-02-16 16:27:57 +01:00
sched !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
syscall syscall: fcntl param3 type to uintptr_t 2026-04-27 12:01:55 -03:00
tools Dockerfile & Docs: Change bitbucket.org/nuttx/tools to github.com 2026-05-25 08:34:45 -03:00
video video: ensure video library is non-empty 2026-05-08 19:51:39 +08:00
wireless include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines !boards: Remove NSH_ARCHINIT and board_app_initialize 2026-05-02 18:36:46 +08:00
.codespellrc arch/sim: replace macOS C++ constructor runtime hack with post-link patch 2026-05-19 07:08:55 -03:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore git: Specify multiple build directories in .gitignore. 2026-05-20 03:06:58 +08:00
.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 feat: add a GitHub action to lint the YAML files 2020-12-15 09:52:04 -06:00
AUTHORS AUTHORS: add Eren Terzioglu 2026-05-20 15:17:00 +08:00
CMakeLists.txt cmake: Fix SIM_TOOLCHAIN using CMake on macOS. 2026-05-25 14:32:48 +02:00
CONTRIBUTING.md docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
INVIOLABLES.md INVIOLABLES.md: Fix a simple alignment and change occurrences of Nuttx 2020-09-03 01:33:05 +08:00
Kconfig tools/stackusage.py: use toolchain binaries instead of Python libraries 2026-03-17 11:26:44 -03:00
LICENSE !boards: Remove NSH_ARCHINIT and board_app_initialize 2026-05-02 18:36:46 +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 docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

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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.