Die temperature sensor conflict

[scjr_dev]

Hi,

I’m using an nRF52810 with nRF Connect SDK v2.5.1. I want to read the internal temperature sensor. I started from the LBS sample and added NSMS to report the temperature.

I have a concern after reading these two threads:

SW got stuck during reading internal TEMP sensor

 accessing the nRF5340 temperature sensor 

My question is: Is it safe to read the internal temperature sensor from the application as long as I enable CONFIG_TEMP_NRF5_MPSL=y?

I’m not fully sure in which situations MPSL accesses the TEMP peripheral and could cause a conflict. Does MPSL only use the TEMP sensor when LFRC calibration is enabled, or is it used in other cases as well?

Thanks 

[Einar Thorsrud]

Hi,

The temperature sensor is own by the MPSL and it is not safe to access it directly. It must be accessed using mpsl_temperature_get() from low priority. See this thread for details.

[scjr_dev]

Ok thanks I did not see this thread.

Just to make sure, since I'm using LFXO, I don't see the TEMP register beeing updated. So in this case you suggest to add this thread to my app ?

K_THREAD_DEFINE(temperature_thread_id, TEMPERATURE_THREAD_STACK_SIZE,
temperature_thread_entry, NULL, NULL, NULL,
K_PRIO_COOP(CONFIG_MPSL_THREAD_COOP_PRIO), 0, 0);


void temperature_thread_entry(void)
{
    while (1) {
        mpsl_temperature_get();    
        k_sleep(K_SECONDS(2));
    }
}

[Einar Thorsrud]

Hi,

Yes, that should work. You could also store the return value of mpsl_temperature_get() or handle it another way that suits your application. It would also be OK to read the TEMP register directly, and it will hold the last result, which may be easier to integrate in your application.