3ff85acb4b
The OTP, read-only (UID, flash size, package) and high-cycle data (EDATA) flash areas only accept 16/32-bit accesses and return a bus error otherwise (RM0481 Table 77). The manual requires the MPU to disable local cacheability for them (RM0481 7.3.2); with the ICACHE enabled and no such region, reading them raises a precise bus error. Until now this was worked around piecemeal: the driver disabled the ICACHE around stm32_get_uniqueid() and the OTP and EDATA word reads, and nucleo-h563zi mapped the 4 KB OTP/RO area non-cacheable in its board code. Other reads, for example stm32_otp_read() or an application reading the OTP on another board, still raised a precise bus error when the ICACHE was enabled. Map 0x08fff000-0x09017fff, which covers the three contiguous areas, as Normal non-cacheable and execute-never with a single MPU region before the ICACHE is enabled. STM32_ICACHE now selects ARM_MPU so that stm32_mpuinitialize() has reset and enabled the MPU by then. Remove the nucleo-h563zi OTP region in the same commit: the Armv8-M MPU faults on an address that matches more than one region, so keeping both would make OTP and UID reads fault on that board. Assisted-by: Claude:claude-sonnet-5-5 Assisted-by: Claude:claude-opus-5-5 Signed-off-by: Ricardo Maurizio Paul <ricardopaul@geotab.com> |
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| .github | ||
| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmessage | ||
| .mcp.json | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
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.