diagnosing 9160 crash due to hardware error

[paul_tanner]

I have a working (hand-wired) prototype that connects to the internet without any problem.

Now I have made a PCB to replicate the same thing and loaded the same software.

Evidently there is a wiring error because the application crashes to the point where connection is made (lte_ready event).

Just before it crashes I get "E: Could not get GPIO Device Binding"

I am looking for the source of this error but cannot find it. (I test each GPIO binding before trying to activate LTE.)

Any suggestions as to where I might look?

[paul_tanner]

Thanks.

It's not from that board.c file as that would show the error with a module prefix.

I'm using NCS 1.5 and have carefully reviewed the schematic.  I suspect a short or something.

The devicetree is correct as it works perfectly on the earlier prototype.

Regards.

[Øyvind]

Thanks for clarifying. It does sound like you need to review the schematic, and debug the HW. 

Kind regards,
Øyvind

[paul_tanner]

OK. It seems to be related to the version of the nrf9160.  Older chips work fine in the new board.  For that reason I think the board is OK.  The above error message is not relevant as that happens with old and newer chips (and it *did* come from board.c).

So I am looking for something else.  Might we need alternative power arrangements?  The crash now seems to be related to the lte_ready event.

I have tried increasing the capacitors on VIN and VCC (as the Actinius doc calls them) 4.7uF.  That did not fix it,

I'd like to be able to say which chip versions and on the modules I'm testing with.  Not sure how to discover that.

Regards, Paul

[paul_tanner]

Correction.  That (2 x 4.7uF) usually fixes it.  Any reason why this should be?

[Øyvind]

Can you please provide more information on what board you are using? Are you using the Actinius Icarus? 

From the Product Change Notification (PCN134) for nRF9160 rev 1 (B0) to rev 2 (B1) it states:
SiP external cap, DEC0, to be changed from 47uF to 4.7uF

[mike_actinius]

Hi,

This is not about the Actinius Icarus and of course all our products have the correct capacitors and are well-tested designs.

The customer has been in contact directly with us as well and this is about a custom board with 1 boost DCDC and 1 buck DCDC in series, powering both the VIN and VCC of a SoM, our solderable module with the nRF9160. We have advised the customer to add more capacitance to his design at the point of feeding VIN (initially there was 100nF which for most applications is fine for our SoM).

Kind regards,

Mike