Secure and Non-Secure Firmware communication

[KLT-ES]

Hi Guys,

I'm looking for some information on how to get data from the secure side to the non-secure side of the firmware.
We are building an NB-IoT GPS tracker which is only activated very rarely. Because of this the power is cut off completely.
There's a single button which enables the power and at the same time is being looked at by the firmware for different push patterns.

As a first move the secure nRF9160 firmware takes over the power enable function from the button in ~15ms,which is good enough.

And now our problem, the secure boot finishes in ~350ms which is enough time to lose the first short button press by the non-secure firmware, we need the secure firmware to process the button events and forward them.

How can we achieve this, could you point me to the right literature?

Thank you,

Lorand

[Didrik Rokhaug]

Hi.

If I understand you correctly, what you want is for the SPM (Secure Partition Manager, the "application" that runs before your application to configure the peripherals as non-secure) to detect the button pattern, and then report it to the application?

If so, I would suggest that you create your own SPM, that first checks for the button pattern, stores the result, then start the main application. The application can then request the result from your custom SPM.

For a guide on how to create your own SPM, and add secure functions that are callable from a non-secure application you can take a look at this guide: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/using-a-custom-secure-partition-manager-wtih-your-application

Best regards,

Didrik