The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Achim Kraus — Mon, 26 Feb 2024 09:36:24 GMT

"-2"

That may be caused by a "none existing CONFIG_COAP_SERVER_HOSTNAME", e.g. "californium.eclipseprojects.org" instead of "californium.eclipseprojects.io". I would recommend, that you add that hostname to the error message with something similar as ("ERROR: getaddrinfo for '%s' failed %d", CONFIG_COAP_SERVER_HOSTNAME, err).

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Håkon Alseth — Mon, 26 Feb 2024 08:53:30 GMT

Hi Tom,

It is very strange that lesson5 does not work, while lesson4 does work on your end.

Both of these are default setup with LTE-M, so unless you have done changes specifically for lesson4, they should both behave equally.

-2 is an errno, which you can check here:

https://github.com/nrfconnect/sdk-zephyr/blob/v3.4.99-ncs1-2/lib/libc/minimal/include/errno.h#L41

Have you added the steps required for exercise 1? for instance setting the hostname for the CoAP server?

Try running "cellfund_less5_exer1_solution" and see if that one runs.

Kind regards,

Håkon

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Tom.Fu — Fri, 23 Feb 2024 05:49:13 GMT

Hi,

It's good to see that It can connect to the LTE network now after I set CONFIG_LTE_NETWORK_MODE_NBIOT_GPS=y. But it failed to get the address information. I don't know what does the return value -2 mean and how to resolve this problem. Many thanks.

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Håkon Alseth — Wed, 21 Feb 2024 09:34:34 GMT

Hi,

You are getting +CEREG: 4 back, are you certain you have coverage for LTE M in your area?

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/nw_service/cereg_read.html?cp=2_2_0_7_6_1

Should you set NB-IoT instead?

CONFIG_LTE_NETWORK_MODE_NBIOT_GPS=y

Kind regards,

Håkon

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Tom.Fu — Wed, 21 Feb 2024 02:19:28 GMT

Hi,

If I issuing the at command by the at_client, does the modem keep the configuration after I program the exercise code to the chip? I have tried this way, but the issue still could not be resolved.

I enable the AT host library in the exercise, but it responded ERROR after the AT%XFACTORYRESET=0 was sent.

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Håkon Alseth — Tue, 20 Feb 2024 09:07:51 GMT

Hi,

[quote user="Tom.Fu"]Sorry, I am not quite understand how to implement running "AT+CFUN=0" [/quote]

Sorry, this was recently changed. Prior versions could reset the modem reset loop restriction by issuing AT+CFUN=0, but recent versions require factory reset.

If you have issues related to issuing at commands, try to use at_client to issue it.

In your case, you need to look at the response, -7, which corresponds to E2BIG:

/**
 * @brief Send a formatted AT command to the modem
 *	  and receive the response into the supplied buffer.
 *
 * @param buf Buffer to receive the response into.
 * @param len Buffer length.
 * @param fmt Command format.
 * @param ... Format arguments.
 *
 * @retval  0 On "OK" responses.
 * @returns A positive value On "ERROR", "+CME ERROR", and "+CMS ERROR" responses.
 *	    The type of error can be distinguished using @c nrf_modem_at_err_type.
 *	    The error value can be retrieved using @c nrf_modem_at_err.
 * @retval -NRF_EPERM The Modem library is not initialized.
 * @retval -NRF_EFAULT @c buf or @c fmt are @c NULL.
 * @retval -NRF_EINVAL Bad format @c fmt, or @c len is zero.
 * @retval -NRF_ENOMEM Not enough shared memory for this request.
 * @retval -NRF_E2BIG The response is larger than the supplied buffer @c buf.
 * @retval -NRF_ESHUTDOWN If the modem was shut down.
 */
int nrf_modem_at_cmd(void *buf, size_t len, const char *fmt, ...);

This means that the buffer you provided was too small for the response.

Kind regards,

Håkon

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Tom.Fu — Tue, 20 Feb 2024 03:35:16 GMT

Hi,

Sorry, I am not quite understand how to implement running "AT+CFUN=0" before running a reset of the nRF9160 in this code. I tried to send the AT command of %XFACTORYRESET=0 to remove this restriction, but it failed to set this command like the screenshot below. And I also tried send the AT+CFUN=0 like this way, it can success to set but the log still freezing in the state like the screenshot below.

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Håkon Alseth — Mon, 19 Feb 2024 10:50:12 GMT

Hi,

I used your .hex file, with mfw v1.3.6:

*** Booting Zephyr OS build v3.3.99-ncs1 ***
[00:00:00.404,571] <inf> Lesson5_Exercise1: Initializing modem library
[00:00:00.646,179] <inf> Lesson5_Exercise1: Connecting to LTE network
[00:00:01.777,008] <inf> Lesson5_Exercise1: RRC mode: Connected
[00:00:02.915,527] <inf> Lesson5_Exercise1: Network registration status: Connected - home network
[00:00:02.915,679] <inf> Lesson5_Exercise1: Connected to LTE network
[00:00:03.182,220] <inf> Lesson5_Exercise1: IPv4 Address found 20.47.97.44

[00:00:03.182,708] <inf> Lesson5_Exercise1: Successfully connected to server

Did you check the former link?

[quote user="hkn"]

Could it be that you're seeing this restriction?

https://infocenter.nordicsemi.com/topic/nwp_042/WP/nwp_042/intro.html?cp=2_3_1

[/quote]

It is quite common that you run into this restriction, especially if you do not run "AT+CFUN=0" before running a reset of the nRF9160.

Kind regards,

Håkon

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Tom.Fu — Mon, 19 Feb 2024 09:38:08 GMT

Hi,

But other code could connect normally every time after I programmed and it still could not connect normally after I tried to update the modem firmware to v1.3.6.

The NCS version I currently use is v2.4.0.

RE: The code for the lesson5 exercise1 of Cellular IoT Fundamentals in the DevAcademy could not be able to connect to the lte network

Håkon Alseth — Mon, 19 Feb 2024 08:53:07 GMT

Hi,

The code worked out of the box at my end (both with your precompiled .hex and on ncs v2.5.2):

*** Booting nRF Connect SDK v2.5.2 ***
[00:00:00.397,338] <inf> Lesson5_Exercise1: Initializing modem library  
[00:00:00.638,214] <inf> Lesson5_Exercise1: Connecting to LTE network   
[00:00:01.569,519] <inf> Lesson5_Exercise1: RRC mode: Connected         
[00:00:02.948,089] <inf> Lesson5_Exercise1: Network registration status: Connected - home network
[00:00:02.948,211] <inf> Lesson5_Exercise1: Connected to LTE network    
[00:00:03.249,725] <inf> Lesson5_Exercise1: IPv4 Address found 20.47.97.44

[00:00:03.250,213] <inf> Lesson5_Exercise1: Successfully connected to server

Could it be that you're seeing this restriction?

https://infocenter.nordicsemi.com/topic/nwp_042/WP/nwp_042/intro.html?cp=2_3_1

Kind regards,

Håkon