About 85-105deg LFXODEBOUNCE register setting of nRF52820

[Masa]

Hello.

There is a description of Extended Operating Temperature in item 8.1 of the specification (v1.3).

It is written that register LFXODEBOUNCE must be changed when using at 85deg or higher, but should this be changed during operation if there is a temperature change?

In this case, measure the die temperature, change it when it detects 85deg or more, and change it again when it becomes less than 85deg?
Also, is there a sample program for that?

SDK ver.17.1 (S140)

[Jared]

Hi,

I assume that you're using our Softdevice.

The LFXODEBOUNCE register should be set once before initializing the Softdevice. The consequence of setting the register to Extended is that the Softdevice will increase the time it waits for the LFXO crystal to start up, since the crystal will take longer time to be stable when the temperature is higher. This means that the only consequence of setting the register to Extended while the temperature is under 85 degrees is that the Softdevice will take longer time to initialize.

In addition, the Softdevice API does not have a function that writes to the LFXODEBOUNCE register, and the Clock peripheral is restricted when the Softedvice is initialized. This means that if you want to set the LFXODEBOUNCE register after the Softdevice has been initialized, you would have to un initialize the Softdevice first. Thus, I would recommend setting the LFXODEBOUNCE once, before you initialize the Softdevice if you expect the temperature to increase over 85 C.

regards

Jared 

[Masa]

Hi, 

Thank you for your answer.

I understand that if there is a possibility of using the MCU above 85deg, this 'LFXODEBOUNCE' should be set to 'Extended', even if the starting temperature is 25deg.

Is there a sample of how to set up this 'LFXODEBOUNCE'?
Is it enough to say 'NRF_CLOCK->LFXODEBOUNCE = 1;' at the beginning of the "main.c" program?

Best Regards

Masa

[Jared]

Hi,

Masa said:

Is it enough to say 'NRF_CLOCK->LFXODEBOUNCE = 1;' at the beginning of the "main.c" program?

Yes, that should be enough. Just make sure that you do it before you initialize the Softdevice.

regards

Jared 

[Masa]

Hi, 

thank you for your reply.

Check with this setting.

Best Regards

Masa