ADC implementation inside TF-M

[Jithin A]

Hi, is there any reference to implement ADC sampling inside TF-M?

I see all the reference there are for implementing ADC in non-secure application. Please point to any documentation or sample application that runs ADC in TF-M instead of non-secure application.

[dejans]

Hi,

There is TF-M secure peripheral partition sample which demonstrates how to use secure peripherals in TF-M partition.

Best regards,
Dejan

[Jithin A]

Thank you for the reference.

I am getting fatal error after configuring a sample application to run ADC in secure, please see below:

fatal error: soc.h: No such file or directory
   19 | #include <soc.h>

When I try to add below include file, I see the fatal error.

#include <zephyr/drivers/adc.h>

Any idea on why the file is not fetched from TF-M?

The same example if I run in non-secure application, it is working fine.

How do I configure ADC to run in secure mode, as I do not see any CONFIG_NRF_ADC_SECURE flag to enable ADC in secure.

Please let me know if I am missing anything.

[Jithin A]

dejans said:

Could you test TF-M secure peripheral partition using NCS v2.5.0?

--> Same error.

I heard device tree or zephyr libraries are not supported by TF-M, I am not sure on this. If so, is there any example application which uses NRF/NRFX library instead to config and read from ADC channels?

[dejans]

Hi,

I have tested secure_peripheral sample in NCS v2.5.0 and I did not observe any errors regardless of CONFIG_ADC being added (and enabled) or not. I built the sample for nrf5340dk_nrf5340_cpuapp_ns build target.

Best regards,
Dejan

[Jithin A]

Hi Dejans,

I can build the secure_peripheral sample in NCS v2.5.0 with no errors

I am getting error only after integrating ADC example into the TF-M.

[dejans]

Hi,

The problem might be that you try to integrate Zephyr sample with TF-M. TF-M is not Zephyr application and Zephyr API cannot be used inside TF-M (including secure service where you would use saadc). Instead, you would need to use nrfx driver directly. You can find examples in modules/hal/nordic/nrfx/samples/src/nrfx_saadc or online at nrfx_saadc.

Best regards,
Dejan

[Jithin A]

Hi Dejans,

Thank you for the response.

dejans said:

The problem might be that you try to integrate Zephyr sample with TF-M. TF-M is not Zephyr application and Zephyr API cannot be used inside TF-M (including secure service where you would use saadc). Instead, you would need to use nrfx driver directly. You can find examples in modules/hal/nordic/nrfx/samples/src/nrfx_saadc or online at nrfx_saadc.

--> Got it, this confirm I cannot use zephyr APIs inside the TF-M.

Thank you for referring to the NRFX lib, will test it and let you know.

[dejans]

Hi,

Thank you for the update.

Best regards,
Dejan