864c97f1d9
ice40_endwrite() computes how many dummy SPI bytes to clock out after
the bitstream to finish FPGA configuration with:
for (size_t i = 0; i < ICE40_SPI_FINAL_CLK_CYCLES + 7 / 8; i++)
`/` binds tighter than `+` in C, so this parses as
ICE40_SPI_FINAL_CLK_CYCLES + (7 / 8) = 160 + 0 = 160, i.e. the "+ 7 / 8"
is a silent no-op. The macro name and the classic `(n + 7) / 8`
ceiling-division idiom (used elsewhere in embedded code to convert a
bit/cycle count into a byte count) make clear the intent was to send
ceil(ICE40_SPI_FINAL_CLK_CYCLES / 8) = 20 bytes (160 SPI clock cycles,
matching the macro name). Instead the unmodified code sends 160 bytes,
i.e. 1280 clock cycles - 8x more than intended.
Fix by parenthesizing the ceiling-division: (ICE40_SPI_FINAL_CLK_CYCLES
+ 7) / 8, which evaluates to 20, restoring the intended 160-clock-cycle
finalization sequence.
Fixes #19367
Assisted-by: Claude Code:claude-sonnet-5
Signed-off-by: yi chen <94xhn1@gmail.com>
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| 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.