Development Issues When Using the nRFx Library in Zephyr

RE: Development Issues When Using the nRFx Library in Zephyr

Vidar Berg — Thu, 04 Sep 2025 07:18:01 GMT

[quote userid="145693" url="~/f/nordic-q-a/124099/development-issues-when-using-the-nrfx-library-in-zephyr/547714"]I was originally developing the SPI using Zephyr's APIs, but found that using a k_timer to trigger SPI data transmission every 1 second resulted in a power consumption of about 29 μA. [/quote]

I don't think you will see much improvement considering the long interval between your transactions. Did you confirm that the added current was because of the CPU, and not leakage, current draw by the SPI slave, etc.?

[quote userid="145693" url="~/f/nordic-q-a/124099/development-issues-when-using-the-nrfx-library-in-zephyr/547714"] could Zephyr's power management shut down these operations during sleep?[/quote]

No.

RE: Development Issues When Using the nRFx Library in Zephyr

joey — Thu, 04 Sep 2025 07:14:26 GMT

I was originally developing the SPI using Zephyr's APIs, but found that using a k_timer to trigger SPI data transmission every 1 second resulted in a power consumption of about 29 μA. I want to directly use the GRTC to trigger the SPIM via DPPI for data acquisition to reduce CPU power consumption. However, since the program uses the DPPI+SPIM approach, could Zephyr's power management shut down these operations during sleep? If it could, how can I ensure that the DPPI+SPIM operations remain active while also allowing the peripherals to enter low power mode after each operation?

RE: Development Issues When Using the nRFx Library in Zephyr

Vidar Berg — Thu, 04 Sep 2025 06:47:15 GMT

Zephyr will enter sleep (System ON) independently of the SPI activity. CONFIG_PM_DEVICE_RUNTIME only affects Zephyr drivers which support the runtime power management which usually involves disabling the peripheral during idle periods. Was the goal to reduce the system current consumption when you decided to use SPI with DPPI and GRTC, or is it to meet timing requirements in your application? The CPU overhead with triggering the SPI transactions is usually negligible (i.e. no significant impact on the average power consumption)

RE: Development Issues When Using the nRFx Library in Zephyr

joey — Wed, 03 Sep 2025 13:52:45 GMT

OK,

In the program, I used the nrfx library to operate the spim, especially combining with dppi to operate the spim. Now, regarding the original power management of Zephyr, how should I operate it to ensure that the device can enter sleep mode normally?

RE: Development Issues When Using the nRFx Library in Zephyr

Vidar Berg — Wed, 03 Sep 2025 13:48:59 GMT

This was a bug which as been addressed in SDK v3.1.0. I recommend upgrading if possible. If not, you can change NRF_SPIM_HAS_ARRAY_LIST to '1' in your SDK.

RE: Development Issues When Using the nRFx Library in Zephyr

joey — Wed, 03 Sep 2025 13:40:30 GMT

However, these functions of mine are undefined.,How should it be set to be enable?

RE: Development Issues When Using the nRFx Library in Zephyr

Vidar Berg — Wed, 03 Sep 2025 13:35:44 GMT

Array list mode is enabled with the NRFX_TWIM_FLAG_TX_POSTINC and NRFX_TWIM_FLAG_RX_POSTINC flags. There is also the NRFX_TWIM_FLAG_HOLD_XFER to configure a transaction without actually starting it.

RE: Development Issues When Using the nRFx Library in Zephyr

joey — Wed, 03 Sep 2025 13:32:05 GMT

However, in the SDK I'm using, I couldn't find the configuration function for the DMA array list, and some of the examples I've looked at also directly accessed the registers.

Now I want to use DPPI to control SPIM. So even though NRFX_TWIM_XFER can be used for transmission, it does not meet the actual application requirements for me.

RE: Development Issues When Using the nRFx Library in Zephyr

Vidar Berg — Wed, 03 Sep 2025 13:27:39 GMT

You should avoid direct register access when using the driver like you are doing in sensor_spim_dma_init(). Otherwise the driver is likely to end up overwriting your configurations.

You can set up your transfers via nrfx_twim_xfer(). See API documentation for relevant flags and helper macros.

RE: Development Issues When Using the nRFx Library in Zephyr

joey — Wed, 03 Sep 2025 12:48:14 GMT

Thank you for your reply

After initializing SPIM with nrfx_spim_init, I was able to communicate normally by calling nrfx_spim_xfer. Then, I configured the DMA array list and used nrfy_spim_task_trigger(spim30_inst.p_reg, NRF_SPIM_TASK_START) to trigger the task. However, when observing the oscilloscope, there were no waveforms and the program was not running properly. What could be the problem?

RE: Development Issues When Using the nRFx Library in Zephyr

Vidar Berg — Wed, 03 Sep 2025 12:34:07 GMT

Hello,

The configurations from your spi30 node in the devictree will not be automatically applied when you are using the nrfx drivers directly like they are when using the Zephyr SPI driver API. Please verify that .frequency value passed to nrfx_spim_init() is configured correctly.

https://github.com/zephyrproject-rtos/zephyr/blob/e9cf74b581a1371f77862eea1e3cf24cadd457c6/samples/boards/nrf/nrfx_prs/src/main.c#L145

Best regards,

Vidar