Unable to initialize modem/at commands

RE: Unable to initialize modem/at commands

Håkon Alseth — Wed, 23 Mar 2022 10:34:17 GMT

Hi Brad,

I'm glad to hear that the issue was resolved! Hope you have a wonderful day!

Cheers,

Håkon

RE: Unable to initialize modem/at commands

brad_57 — Tue, 22 Mar 2022 21:01:54 GMT

Hi Håkon,

I'm happy to report this issue has been resolved by reflowing the nRF chips, and making sure they're seated perfectly. At least one of the pads on the bottom of the chips must've not been connected properly, and we were unable to see it. The layout seems good for the moment, but if we see other issues we'll proceed with opening a ticket for layout review.

Thank you so much for your assistance while we worked through this,

Brad

RE: Unable to initialize modem/at commands

Håkon Alseth — Mon, 21 Mar 2022 08:35:06 GMT

Hi Brad,

I would recommend that you open a private ticket and request for review of the design, just in case.

If you need a NDA to be in place, this should be done through our sales department. If you do nto have the contact details of your local sales manager, please send me a direct message with your location and I'll provide his/her's contact details.

Kind regards,

Håkon

RE: Unable to initialize modem/at commands

brad_57 — Fri, 18 Mar 2022 19:46:51 GMT

Hey Håkon,

We haven't had our layout reviewed by you guys yet. I mentioned it to the team, and we're considering opening a private support ticket for it, as we wish to keep the design confidential. Is there a basic NDA we could enter (or something similar) to ensure it stays confidential?

I shared that PDF with the electrical engineer to make sure the layout is consistent with it. Looking at the schematic, we do spec a 4.7uF cap for DEC0. The actual cap on my board may be 10uF though.

Thank you again,

Brad

RE: Unable to initialize modem/at commands

Håkon Alseth — Fri, 18 Mar 2022 09:04:50 GMT

Hi Brad,

Have you gotten the layout reviewed by us?

When going from revision 1 to revision 2, there are a couple of things that needs to be handled, as per this informational notice:

https://infocenter.nordicsemi.com/pdf/pcn_134_v1.0.1.pdf?cp=2_0_2_3

A very crucial change is this:

"SiP external cap, DEC0, to be changed from 47uF to 4.7uF"

Kind regards,

Håkon

RE: Unable to initialize modem/at commands

brad_57 — Wed, 16 Mar 2022 20:35:48 GMT

Hi Håkon,

Just the one is showing this issue. I have another one that the programming app won't detect, and I suspect there's a bad solder joint on it. I'll be able to test more with an electrical engineer next week. Worst case scenario, we should be able to determine if this is the issue with both boards next week.

I've re-downloaded mfw v1.3.1 and programmed it onto the nrf, but am seeing the same results.

Do you know if there's anything else worth trying/looking into in the meantime?

Thank you,

Brad

RE: Unable to initialize modem/at commands

Håkon Alseth — Wed, 16 Mar 2022 10:49:33 GMT

Hi,

[quote user=""]I only have one working board with the nrf9160 siaa b1.[/quote]

How many devices are showing the initial problem?

Could you try to reprogram the problematic devices with mfw v1.3.1, and see if this changes the behavior in any way?

[quote user=""]What could be causing the modem init to fail?[/quote]

It can be any number of things, but the usual scenario is if the modem fw is not of a newer version.

Kind regards,

Håkon