nRF9131 modem Init failure

[Emmett Tagliere]

Hi, having a little of an issue and would appreciate your support:

When bringing up a board which has the nRF9131 and the nPM6000 I'm getting the following error when doing nrf_modem_lib_init();      

 Modem fault! PC: 0x001299C2, Reason: 0x010 - ASSERT

[00:00:07.263,732] <err> nrf_modem: Modem library initialization failed, err -5
[00:00:07.263,763] <dbg> nrf_modem: nrf_modem_lib_init: Modem init callback: 0xdc7d
[00:00:07.263,763] <err> nrf_modem: Modem library did not initialize: -5
nrf_modem_lib_init failed, err: -5

I tried:

Changing the modem firmware to different versions,

testing on different boards,

re-assembly and probing for any shorts,

adding capacitors near the nPM6000 Vin,

Changing the TCXO to a different model.

still got the same error

Any tips on how to solve this would be much appreciated

Thanks!!

[Emmett Tagliere]

Hi, 

Modem FW: mfw_nrf91x1_2.0.4.zip

NCS version: v3.1.0

Thanks

[Michal]

Thank you for the information.

Best regards,

Michal

[Michal]

No, not yet.

It may be worth checking. I would recommend making another (private) ticket with your design (schematic in PDF and gerber files at the minimum) and then one of our hardware experts will check that. 

By the way, have you tested this on an nRF9131 EK?

Best regards,

Michal

[Emmett Tagliere]

alright, will do.

I have tested on the EK yes, worked fine.

best regards

[Michal]

I have a feeling it may be possibly be a footprint or soldering issue with some of the internal modem connections being shorted, causing error in communicating with the modem.

Errno -5 is EIO, which would make sense, if the application core is unable to contact the modem because of that.

But that's just my intuition.

Best regards,

Michal

[Emmett Tagliere]

ok, I hope thats the case.

I'll try re-soldering again, while also sending the design files for review in a new private ticket.

Best regards and thanks

[Emmett Tagliere]

Hi, I re-assembled the board a few times and tried again, still same issue, and I'm pretty sure there weren't shorts in all those times of re-assembly. (it was on fresh new boards each time). 

Also, important to note, I dont get that error on the modem firmware that came on the chip, so if I just plug the board in and start the application, nrf_modem_lib_init(); returns successfully. Only after doing a modem firmware upgrade the -5 error happens. 

So I wonder if there is something with the modem firmware / NCS / nrf9131 / nPM6000 versions that mismatch, which is causing the updated firmware to fail.

Looking forward to your insights.

Thanks

[Emmett Tagliere]

Also, I'm using softSIM, if that can also cause an issue. 

Regards

[Emmett Tagliere]

Hi, sorry for the ongoing messages, but wanted to updated:

I tried to switch between my nRF9131 and the nRF9131 that's on the EK I had around, and now everything works perfectly. so its not a short or hardware, I think there may be something wrong with the specific revision I have. 

The chip that works (the one I took from the EK):

AO

2346AH

The chips that don't work (at least the 5 I tested):

AO

2402G7

Would love your help on how to make the chips I have to work like the EK version does, since we already bought a big quantity of them.

Thanks!

[Øyvind]

Hello, 

Michal is currently out of office and I've been asked to follow-up this ticket. If OK with you, can we continue the discussion in ticket #358011?

Kind regards,
Øyvind

[Emmett Tagliere]

Hi, 

Yes lets continue in ticket #358011

Best regards