nrf9160 SIM_VDD is always 0V

Hi,

On the other hand, checking the board voltages I have detected that the SIM_VCC voltage coming out of the nrf9160 is always at 0V.

The SIM_1V8 net can be turned off when the device is in PSM or eDRX, but will be on before entering such a sleep mode.

If the voltage is always at 0V, it can indicate that there's a problem with the initial communication with the SIM itself.

If that is the case, certain AT commands, like AT+CEREG will reflect this (return 90 in this case):

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/nw_service/cereg_read.html?cp=2_1_7_6_1

As well as AT%XSIM can be used for checking the status of the SIM card:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/access_uicc/xsim_read.html?cp=2_1_12_0_1

Is it possible that the two errors are related?

If it is the same device which shows 0V on SIM_1V8, it will fail firmware-wise as well. I would assume that more than the one line would be printed if there was a SIM communication error (it should have been caught much earlier in the process).

Kind regards,

Håkon

I get the following errors:  

lte_lc: Failed to enable eDRX, reported error: 65536
gnss_sample: Failed to initialize LTE link controller

The version of the SDK I am using is the nRF Connect SDK v1.9.0. I have also tested the same code directly on a Thingy:91 board without SIM card and this error does not appear and I can initialize the modem without errors.

The thingy:91 has a nrf9160 SICA B0 and I have a B1 on my board, maybe this is the difference that makes the error?

Thank you very much.

JP.

Did you check the status of the SIM using the former AT commands?

Could you try to use the at_client + LTE Link monitor PC application, and issue the following AT commands and share the full output?

AT+CEREG=5

AT+CFUN=1

AT+CFUN?

LTE LinkMonitor should automatically apply other AT commands.

Kind regards,

Håkon

On my board I don't have a USB connector to use the LTE Link Monitor application.

Testing the software on the Thingy:91 without a SIM I don't get the EDRX error so I understand that to initialize the EDRX I don't need the SIM to init the module. Is it possible?

With none of the example projects I can initialize the LTE. Could it be because I have the nrf9160 B1 version, regarding the B0 version, do I have to make any modification in the firmware?

Thank you very much.

Hi,

user94498 said:

On my board I don't have a USB connector to use the LTE Link Monitor application.

You can connect the GPIOs to a generic USB-UART converter and use that.

user94498 said:

Testing the software on the Thingy:91 without a SIM I don't get the EDRX error so I understand that to initialize the EDRX I don't need the SIM to init the module. Is it possible?

With none of the example projects I can initialize the LTE. Could it be because I have the nrf9160 B1 version, regarding the B0 version, do I have to make any modification in the firmware?

If none of the examples work, I highly suspect there's an issue with your hardware connection towards the SIM card. Check if you have inverted the footprint to the SIM, and ohm from each pin of the SIM card holder to the respective nRF pins to see if it matches.

Kind regards,

Håkon

Hi,

user94498 said:

On my board I don't have a USB connector to use the LTE Link Monitor application.

You can connect the GPIOs to a generic USB-UART converter and use that.

user94498 said:

Testing the software on the Thingy:91 without a SIM I don't get the EDRX error so I understand that to initialize the EDRX I don't need the SIM to init the module. Is it possible?

With none of the example projects I can initialize the LTE. Could it be because I have the nrf9160 B1 version, regarding the B0 version, do I have to make any modification in the firmware?

If none of the examples work, I highly suspect there's an issue with your hardware connection towards the SIM card. Check if you have inverted the footprint to the SIM, and ohm from each pin of the SIM card holder to the respective nRF pins to see if it matches.

Kind regards,

Håkon