Cannot get NB-IoT connection with nRF9160 DK

[SergioT]

From what I could see the Asset_Tracker example works in LTE, not in NB-IoT. How can I test NB-IoT?

I would like to get some hint on what example to use and what to do to get nRF Cloud connection through NB-IoT so that I can start my development from a working platform.

I have nRF9160 DK board, iBasics SIM card and also a 1nce SIM card. I am based in Munich and must develop a project based on the nRF9160 chip.

All tips are welcome.

[MJD093]

Just to clarify, NB-IoT is a part of LTE. What you want to swap the radio configuration from LTE-M to LTE-NB. ;)

[SergioT]

The problem is I cannot get any connection with the Asset_Tracker example. I'd like to have one example that works so I can build on it. Our aim is to use NB-IoT for our application... Any tips?

[MJD093]

I know we have discussed this in the other question, but have you tried the at_client sample yet? I know this isn't what you are looking for as you would like the asset tracker but it is important to verify you can connect to a network or it will never work even with the correct configuration

[SergioT]

I will test it now: I'll let you know the result.

[SergioT]

The at_client example is working: I get LTE green in nRF Connect!

What is the next step?

[MJD093]

Ok great, so at least you know your set-up is working.

The next thing is to configure the asset tracker application to NB-IoT. Now you said you tried the CONFIG_LTE_NETWORK_MODE_NBIOT=y option and it didn't work. What exactly was the serial log for that attempt? Did it fail because of a connection error or because the human interaction part of the connection wasn't completed? Remember, there is a human interaction element to connecting the DK to nRF Cloud, it's not just flash the program and it will do the rest, you have to pair it to the nRF Cloud with button and switch inputs.

If it isn't changing the system set-up to NB-IoT, you can always try the direct approach and comment out both the LTE-M configuration for network_mode[] and the define check for NB-IoT in the lte_lc.c file and leave only the network_mode[] line for NB-IoT.

[SergioT]

I use a very good editor and I searched in all directories and all files of the project and I found only definitions for CONFIG_LTE_NETWORK_MODE_LTE_M and nonoe for NBIOT. I therefore replaced all

CONFIG_LTE_NETWORK_MODE_LTE_M by CONFIG_LTE_NETWORK_MODE_NBIOT.

Now after I run on SES and then check in nRF Connect, the XSYSTEMMODE is 0,1,0,2 which is correct. However it never connects...

What is wrong?

[MJD093]

Thats... strange? It is in the master file as well as in my v0.4.0 release tag of the repos

https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/drivers/lte_link_control/lte_lc.c#L46

But anyway, at least your modem's XSYSTEMMODE is now configured correctly.

So what is it doing, can you post the serial log?

[SergioT]

After searching the LTE became green but then the module made a reset. 

AT+CPIN?
+CPIN: READY
OK
AT+CPINR="SIM PIN"
+CPINR: "SIM PIN",3
OK
AT+CIMI
901405100336032
OK
+CGEnrf_cloud_connect failed: 22
V: ME PDN ACT 0,0
+CNEC_ESM: 50,0
+CEREG: 5,"CB52","023AAF11",9
+CIND: "service",1
+CIND: "roam",1
AT+COPS=3,2
+CGEV: ME PDN DEACT 0
+CEREG: 0,"CB52","023AAF11",9
+CIND: "service",0
+CIND: "roam",0
+CGEV: ME DETACH
%CESQ: 255,0
%XSIM: 1
%XSIM: 0
OK
***** Booting Zephyr OS v1.14.99-ncs1 *****
AT+CGDCONT?
Flash region Domain Permissions
00 0x00000 0x08000 Secure rwxl
01 0x08000 0x10000 Non-Secure rwxl
02 0x10000 0x18000 Non-Secure rwxl
03 0x18000 0x20000 Non-Secure rwxl
04 0x20000 0x28000 Non-Secure rwxl
05 0x28000 0x30000 Non-Secure rwxl (...)