nrf52 Low temperature issue

RE: nrf52 Low temperature issue

Susheel Nuguru — Tue, 31 May 2016 08:20:30 GMT

Then this is the first time I am hearing suck problem which is not crystal clock related. I need to get the chip here so that we can test it. We have not heard this from any customers.

RE: nrf52 Low temperature issue

jayesh — Mon, 30 May 2016 09:47:42 GMT

Aryan i used internal RC oscillator for time being instead of 32Mhz crystal but even after that i am facing same problem. I think even external crystal is not an problem. your views ??

RE: nrf52 Low temperature issue

Susheel Nuguru — Mon, 09 May 2016 10:22:32 GMT

OK Thank you, will wait for your updates :)

RE: nrf52 Low temperature issue

jayesh — Mon, 09 May 2016 09:53:00 GMT

Aryan i am not having CL capacitor with that specification so need to do some arrangement. Might take a while for arranging that since its not available in Digi Key also. Will update you as soon as i test.

RE: nrf52 Low temperature issue

Susheel Nuguru — Mon, 09 May 2016 07:01:41 GMT

Any updates here Jayesh?

RE: nrf52 Low temperature issue

jayesh — Fri, 06 May 2016 11:52:59 GMT

Ok let me see if that works or not..

RE: nrf52 Low temperature issue

Susheel Nuguru — Fri, 06 May 2016 11:43:52 GMT

Hi Jayesh,

I cannot access that link. It is possible that the different crystal capacitor value is the issue here, Then you need to change the board CL value to suit it.

RE: nrf52 Low temperature issue

RK — Fri, 06 May 2016 11:06:03 GMT

12pF may or may not be correct, sounds like the board works fine at room temperature. You can do the maths to work out whether 8pF or 12pF is correct for your crystal. However .. one thing which will change with temperature is the capacitance of those capacitors, and the smaller they are, the more effects there may be.

Normally I thought that capacitance decreased with decreasing temperature, which ought to push the capacitance back down towards 8pF which you'd think would be more correct, however it's possible that if your crystal and loading capacitors are right on the edge of spec both for capacitance and ESR, as you cool the board perhaps the changes push it out of spec and the 32MHz crystal stops working. Or possibly the 32kHz crystal stops working, you should look at that too.

RE: nrf52 Low temperature issue

jayesh — Fri, 06 May 2016 10:43:50 GMT

Aryan i found out the CL capacitor in 32MHz crystal is 12PF instead of 8PF. Can this be an issue ?

RE: nrf52 Low temperature issue

jayesh — Fri, 06 May 2016 10:20:10 GMT

Aryan please find the below link for our reference design,

mega.nz/

You can download reference design pdf attachment through above link.

Part number for 32MHz crystal is "CX2016DB32000D0FLJCC" Part number for 32KHz crystal is "ABS06-107-32.768KHZ-T"

You can find above part number data sheet from Digi Key.

RE: nrf52 Low temperature issue

Susheel Nuguru — Fri, 06 May 2016 09:47:00 GMT

Can you please tell me which external crystal you are using? and also please give me the reference design you are using to make the board schematics. Maybe there is a possibility that the CL value for the crystal is different and needs tuning with the CL value for the board

RE: nrf52 Low temperature issue

jayesh — Fri, 06 May 2016 09:43:46 GMT

We are using external crystal of 32 MHz for radio and 32 KHz for MCU.

RE: nrf52 Low temperature issue

Susheel Nuguru — Fri, 06 May 2016 09:38:21 GMT

oh, I saw a case exactly with the same problem as yours, I thought it was you. OK then, we can continue here. You not need to open a new case. Can you tell me one thing, are you using external crystal for 64MHz or are you internal clock?

RE: nrf52 Low temperature issue

jayesh — Fri, 06 May 2016 09:21:09 GMT

Aryan no problem with that but how will i be updated in Support portal since i don't have any account in Nordic Support portal.

RE: nrf52 Low temperature issue

Susheel Nuguru — Fri, 06 May 2016 07:36:15 GMT

Hi Jayesh, I took your case in support portal and will guide you there, once it is done, we can update this thread. Is that OK?

RE: nrf52 Low temperature issue

jayesh — Thu, 05 May 2016 06:56:19 GMT

Aryan i am not use to with nrfprog. Can you guide me how to collect data using nrfprog. For DCDC yes we have used reference layout of DCDC i have consulted that with our hardware team.

RE: nrf52 Low temperature issue

Susheel Nuguru — Wed, 04 May 2016 19:40:41 GMT

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.

RE: nrf52 Low temperature issue

jayesh — Wed, 04 May 2016 12:14:57 GMT

Any inputs aryan ???

RE: nrf52 Low temperature issue

jayesh — Wed, 04 May 2016 10:59:28 GMT

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.

RE: nrf52 Low temperature issue

Susheel Nuguru — Wed, 04 May 2016 10:09:17 GMT

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?

RE: nrf52 Low temperature issue

Susheel Nuguru — Wed, 04 May 2016 08:59:48 GMT

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.