Missing transactions on SPI slave

RE: Missing transactions on SPI slave

Hung Bui — Wed, 04 Sep 2024 08:48:48 GMT

Hi David,
I'm glad that you find the issue.

As far as I know the SPI hardware should support changing CPOL in CONFIG register. So either it's not supported by current hardware or the must be a bug in the software to configure CPOL. I will report this. Let us know if you find out something.

RE: Missing transactions on SPI slave

David Demelier — Wed, 04 Sep 2024 07:43:16 GMT

Hi,

Thank you for your quick answer. We have investigated the issue with also a master written in a separate framework (STM + Cube IDE) and we experienced the same issue. We then inspected through a dedicated SPI oscope plugged into the lines and saw the that the oscope did not interpreted the frames correctly. Even though both the master and the slave did have the exact same configuration the problem stayed.

We fixed the issue by removing the SPI_MODE_CPOL in both slave zephyr implementation, the master zephyr implementation, and also in the custom other master for STM + Cube.

We are still trying to understand why removing the option fixes the issue while the configuration was equally set on both side.

RE: Missing transactions on SPI slave

hmolesworth — Tue, 03 Sep 2024 16:46:49 GMT

Might not help, but I would recommend using at least high-drive on all output pins on both master and slave, including /CS. Also a 'scope may prove more useful than a logic analyser, should there be one to hand.

			nordic,drive-mode = <NRF_DRIVE_H0H1>;

RE: Missing transactions on SPI slave

Hung Bui — Tue, 03 Sep 2024 11:06:34 GMT

Hi David,

I couldn't find any similar issue reported for nRF54L before. I think it's not an issue with the experimental support of the chip.

But I don't see a problem with the code you provided.

Could you check with a logic analyzer to see what exactly transmitted over the SPI lines ?
We need to check if the issue is on the SPIM transmitting or on SPIS receiving.

Do you have 2 nRF52 DK to verify if it's the issue on NRF54L or can also be reproduced on nRF52 ?