Strange SPI clocking w/S140 (Update: S132 as well) enabled

RE: Strange SPI clocking w/S140 (Update: S132 as well) enabled

bjorn-spockeli — Fri, 21 Apr 2017 06:13:24 GMT

No problem, I'm happy to help :)

RE: Strange SPI clocking w/S140 (Update: S132 as well) enabled

Daniel Sullivan — Fri, 21 Apr 2017 01:32:44 GMT

Wow, this is a rediculously weird one. After blowing away my project folder and replacing it with the zip and still getting the same issue, I removed literally every line from the board (an unused I2C bus and a couple of buttons as well as the control lines for the display (all of which were inactive)) and like magic I'm getting a clean trace again.

sigh you can chalk this up to "user neglecting to troubleshoot absolutely EVERYTHING before asking for support". Thank you for your time you wasted on me :) (as a developer myself I know how annoying people like myself are)

RE: Strange SPI clocking w/S140 (Update: S132 as well) enabled

bjorn-spockeli — Thu, 20 Apr 2017 14:06:55 GMT

I changed the pins to P0.03 and P0.04 and compiled the project. You can see the logic trace below, I see no synchronisation issues. I just have to flash the example to the NRF52840 kit and then to the trace right?

RE: Strange SPI clocking w/S140 (Update: S132 as well) enabled

Daniel Sullivan — Wed, 19 Apr 2017 11:51:01 GMT

Hi Bjørn, thank you for looking into this. It's really appreciated. I'm at a loss having traced it all the way back to the DMA controller. It looks like the clock is generated in hardware?

The code in the zip is a little different to the code in the post. I've simplified it all the way down to a single nrf_drv_spi_transfer.

Please ignore the warnings about unused variables - it's just code paths I've commented out.

My environment is the nRF52840 PDK using pin 3 (P0.3) as SPI CLK and pin 4 (P0.4) as SPI MOSI (no other lines). I have tested on other ports and have the same issue.

Thank you again.

RE: Strange SPI clocking w/S140 (Update: S132 as well) enabled

bjorn-spockeli — Wed, 19 Apr 2017 10:33:29 GMT

Can you zip the project folder from SDK v13 and attach it to the question? I would like to see if I can reproduce the behavior.