OPTIGA Trust X With OpenThread

[tejaChintalapati]

Hello,

I am trying to integrate OPTIGA Trust X with the OpenThread example, "mqttsn_sleepy_subscriber"(from nRF5_SDK_for_Thread_and_Zigbee_v4.1.0 SDK). I tried adding code from "ifx_optiga_custom_example" project and fix most of the warnings and errors.

The ifx_optiga_custom_example uses RTC2 peripheral to delay and other things. You can see the same in "pal_os.c" file. The problem is, Open Thread stack needs RTC2 peripheral. This post says that I cannot use RTC0 and RTC1 peripherals as well as they are being used by Softdevice and app_timer respectively. If I try to use RTC0 peripheral, the code compiles okay(I can't do the same with RTC1 and RTC2 peripherals, for they will give an error saying the handlers are already defined elsewhere) but the handle never reaches the interrupt handler(In pal_os.c -> ifx_rtc_handler();) even after the event(In optica_util.c -> optiga_util_open_application() -> pal_os_timer_delay_in_milliseconds(1);)

I would normally be happy to tweak the code. However, because this is a security solution, I am hesitating to make significant changes to the underlying code. I fear these changes may introduce bugs. Is there any other way to integrate the OPTIGA Trust X with the Open Thread examples without doing significant code changes?

Thanks in advance for your help 

[Jørgen Holmefjord]

Hi,

Correct, RTC2 is used by the IEEE 802.15.4 radio driver and OpenThread stack, see Thread nRF52840 peripheral requirements. The example you mention does not include BLE, and will therefore not use a softdevice. If you do not plan to use a softdevice, you should be able to use RTC0 for the Optiga Trust X library.

Best regards,
Jørgen

[tejaChintalapati]

Thanks for the response.

I'll try to investigate why the program never reacher the interrupt handler even after it's triggered. Probably not initialised correctly. Shall update this post after the results.

[tejaChintalapati]

Thanks Jorgen. The problem is that I didn't initialise the Low-Frequency clock before calling nrf_crypto_init() which would initialise the RTC.

So, I added the code for initialising the Low-Frequency clock, before calling nrf_crypto_init() function and everything's working great! Such a silly mistake but hey, we live, we learn and we forget

Thanks for your help. I appreciate it.