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The rp2350 holds 4096 rows of 24 bit one-time-programmable memory, which the port did not expose at all. This adds a driver on the NuttX efuse interface, registered by the common board bringup as /dev/efuse. The driver uses the ECC interpretation of a row, in which 16 bits carry data and the remaining 8 carry a Hamming code, so the OTP appears as a flat space of 4096 * 16 bits for the efuse field descriptors to index: a descriptor at bit offset N refers to bit N % 16 of row N / 16. That matches the row numbers already listed in hardware/rp23xx_otp_data.h. Reads come from the chip's ECC-translated window and have no side effects. Rows are locked in pages of 64; a page locked against reads would raise a bus fault, so the lock is checked first and reported as an error instead. Programming needs the separate RP23XX_OTP_WRITE option, which defaults to off; without it a write returns EPERM and no programming code is built at all. When enabled, a row is programmed as a whole through the bootrom, since the ECC bits cover the whole row. For the same reason a row that already holds data cannot be modified, and such a write is rejected rather than left to corrupt the row's ECC. Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: Marco Casaroli <marco.casaroli@gmail.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 | ||
| .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.