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The i.MX RT1176 pairs the Cortex-M7 with a Cortex-M4 that NuttX left in ROM-held reset. This backend lets NuttX on the CM7 run the CM4 as an RPTUN remote. The loader writes the CM4 ELF through the LMEM backdoor window, the boot vector goes into IOMUXC_LPSR_GPR0/1 as the backdoor alias of the code TCM (the CM4-native address does not boot, which NXP's MCMGR also assumes), and SRC releases the core. A released slice cannot be held in reset again: a software reset is a pulse after which the core restarts from the boot vector. Stop therefore parks the core in a wfi loop written over the start of its image, and the next start reloads the image. Virtqueue kicks travel on MU-A channel 0. A kick into a full mailbox is coalesced, because the remote rescans every virtqueue on any kick. SRC_SRMR is set so a CM4 lockup resets only the CM4 instead of the whole chip. The board supplies the remote name, the ELF path, the address environment, the boot vector and the autostart choice through imxrt_rptun_init(). Gated by IMXRT_HAVE_CM4, which only the MIMXRT1176 selects; selects DEV_SIMPLE_ADDRENV for libmetal. Assisted-by: Claude:claude-fable-5-1 Signed-off-by: Lourens Naude <lourens@bearmetal.eu> |
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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. For first-time contributors, building the simulator locally is a useful way to verify the development environment before submitting changes.
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.