Does Clock source has effect on Communication stability at different Operating temperatures

[Pradeep9848Baruva]

As we are performing climate tests for custom PCB based on Nordic nrf52832 SOC, in low temperature i.e -20 Deg C the communication is not stable.
After verifying the HFCLKSTAT  register the registering SRC is switching between RC and XTAL clock. So we changed the changed clock source to only external clock using
API sd_clock_hfclk_request() to force the soft device to use the external crystal as HF clock source and now communication is stable at low temperature.

Here the question is
will Clock source effect the communication stability in different temperatures?

SDK: 15.3

Softdevice version: 6.1.1

[haakonsh]

As we are performing climate tests for custom PCB based on Nordic nrf52832 SOC, in low temperature i.e -20 Deg C the communication is not stable.

 Can you share some more information on this issue?  

After verifying the HFCLKSTAT  register the registering SRC is switching between RC and XTAL clock.

 Can you rephrase this statement, I did not understand what you meant. Are you talking about the LFCLK or HFCLK? 

will Clock source effect the communication stability in different temperatures?

 Well, any crystal oscillator will be more accurate than an internal RC oscillator, especially at temperature extremes. 

[Pradeep9848Baruva]

haakonsh said:

Can you share some more information on this issue?  

While Performing climate test at ambient temperature -20 Deg Celsius  the ble dongle (nrf52832 SOC which acts as peripheral device) when tried to connect to mobile (which acts central device) which gets connect and disconnect very frequently without disconnect request from mobile even mobile is close to ble dongle. This behavior is not their when the ambient temperature is normal ( ~<0 to  25> Deg Cel).

haakonsh said:

Can you rephrase this statement, I did not understand what you meant. Are you talking about the LFCLK or HFCLK?

I meant only HFCLK

haakonsh said:

Well, any crystal oscillator will be more accurate than an internal RC oscillator, especially at temperature extremes.

In our application ble dongle is not battery powered  and we don't have Power limitation, if we use only crystal oscillator as  HF clock source will it work at all extreme temperatures i.e (-40 deg to 85 deg Celsius which is operating temperature range of nrf52832)

[haakonsh]

Pradeep9848Baruva said:

While Performing climate test at ambient temperature -20 Deg Celsius  the ble dongle (nrf52832 SOC which acts as peripheral device) when tried to connect to mobile (which acts central device) which gets connect and disconnect very frequently without disconnect request from mobile even mobile is close to ble dongle. This behavior is not their when the ambient temperature is normal ( ~<0 to  25> Deg Cel).

 If you could gather a debug log from the nRF device and a sniffer trace of the failing communication that would help a lot. 

Pradeep9848Baruva said:

In our application ble dongle is not battery powered  and we don't have Power limitation, if we use only crystal oscillator as  HF clock source will it work at all extreme temperatures i.e (-40 deg to 85 deg Celsius which is operating temperature range of nrf52832)

 Then at least the current workaround to run the HFXO continuously won't impact you.