nrf52 Low temperature issue

[jayesh]

I am using nRF52832 with SDK 11.0.0 and S132_V2.0.0 for my application. My beacon is inside Refrigerator where temperature varies from -2 to 20 degree.My Beacon code is in Pheripheral mode.

I have found following issue with my hardware.

If I put hardware in Refrigerator then I found that at low temperature(< 0 degree) after some time advertisement goes off. If I took out hardware out of cooler then after some time it starts advertisement again. Please note I have enabled internal DC to DC converter in nRF52. One thing i have done that i have disable DC to DC converter and test again in cooler then advertisement doesn't go off and works ok. But that to is not 100% reliable.

Same thing when i try with third party nRf51 module all is working good. I am keeping both nRf51/52 Beacons inside refrigerator. After sometime nRf52 stops advertising but nRf51 is working good whole day at +-2 Degree celsius.

Now when i expose this nRf52 hardware at room temperature then its working good. Its advertising as well as connecting whole day.

So i am bit confuse why this thing is not working at 0 degree celsius, Since as per data sheet it should work upto -40 degree celsius.

Even all the components which i have used in this Beacon Hardware all can work upto -40 to 75 degree celsius.

A quick reply would be quite helpful..

[Susheel Nuguru]

That is strange, I will talk to someone who might know more about testing the chip in the same conditions that you did. I will come back to you soon.

[Susheel Nuguru]

Hi Jayesh,

Can you please read your FICR contents using nrfjprog and give us the values here. We suspect probably that beacon might have been calibrated wrong (very rare to happen)? Also please mention if you are using Crystal of external clock. Can you also put the code of how you are enabling and disabling DC-DC?

[jayesh]

Hi Aryan,

I have read the content of FICR resistor keeping my Beacon in debug mode. I an attaching Screenshot of FICR structure Watch window.

I am using 32MHz crystal for our Custom BLE module and 32 KHz for MCU.

For enabling DC - DC converter i am enabling DCDCEN register. I am using below line in my Initialization code for Enabling it

NRF_POWER->DCDCEN = (POWER_DCDCEN_DCDCEN_Enabled << POWER_DCDCEN_DCDCEN_Pos);

For disabling DC DC i am just commenting DCDCEN register line since by default DC DC mode is disabled.

Even i have tested this thing with 3 to 4 nRf52 Beacon board but same thing happens.

[jayesh]

Any inputs aryan ???

[Susheel Nuguru]

Is it possible to attach the FICR values as text file, its easier when you do this from nrfjprog. Also did you use reference layout that is given for DCDC? There is a separate design for layout when using DCDC.