nrf9161 custom board - sim card problems - CEREG:90

[RicPT]

Hi.

I have a custom board with a NRF9161. The nrf91's LTE block connects to the sim holder through a NX3DV2567HR switch and an TPD3F303DQDR ESD protection. 

I'm using a very simple firmware just to confirm if all is working but I always get a "CEREG:90" response. 

I've checked with an oscilloscope that the nrf9161 is sending the SIM_CLK signal at the beginning of the connection, but I never see any changes in the SIM_VCC pin (always at 0V). A stable 1.8V bus is feeding the VDD_GPIO. I've made this test in two different boards and got the same result.

Can anyone suggest any good strategy to debug and solve this?

Thank you all in advance.  

[Asbjørn]

Hello Ricardo,

are you able to share the details on how you have implemented the SIM interface and component setup/schematic?

The CEREG:90 response means:

• 90 – Not registered due to Universal Integrated Circuit Card (UICC) failure
• From overview here: https://docs.nordicsemi.com/bundle/ref_at_commands/page/REF/at_commands/nw_service/cereg_read.html

This would be as expected if the VDD_SIM is always 0V. Is there a short on the board? Could you probe on the VCC_SIM and GND and see if for some reason there's a short?

Best regards

Asbjørn

[RicPT]

Thank you so much for your answer.

I've checked that already, and there is no short circuit to the ground on the VCC_SIM pin. I imagined that the cereg:90 is due to the lack of power to the card-related components.

That part of the schematic is as follows (CD pin is at GND when card is inserted). Independently from having or not having installed these 3 components in the board, I'm unable to get the VCC_SIM 1.8V at the supply pins of these 3 components. This code is working in the 9161DK.

I considered soldering issues, but I have the same behaviour in 2 units of the custom board with the same result. I also don't know how relevant it might be, but the modem firmware is updated to the latest version.

Thanks again in advance for other ideas you might have.