OceanfromXiaomi opened a new pull request, #17950: URL: https://github.com/apache/nuttx/pull/17950
### Summary This change updates the definition of the rwcnt (read word count) bitfield in ctucanfd_frame_fmt_s. Previously, rwcnt was defined as a 4-bit field, limiting its maximum value to 15. However, according to the CTU CAN FD hardware specification, this range may be insufficient to correctly represent the frame size excluding the FRAME_FORMAT word, especially for larger CAN FD frames. To address this limitation, the bitfield width of rwcnt is increased to support a larger range. At the same time, the layout of ctucanfd_frame_fmt_s is adjusted to ensure that the overall structure size remains a multiple of 4 bytes, which is required by the hardware interface and DMA access constraints. This change improves correctness and robustness when handling CAN FD frames with larger payloads. ### Impact Drivers / Hardware: Improves compatibility with CTU CAN FD hardware by correctly representing larger frame sizes. API / ABI: Internal structure layout change only; no user-facing API changes. Compatibility: No impact on existing applications that rely on standard CAN or smaller CAN FD frames. Existing code continues to work as before. Build / Documentation / Security: No impact. ### Testing In the QEMU environment on an Ubuntu host, the Vela project with CAN support was executed, and verification confirmed that CAN communication and data transmission operate correctly. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
