Turning the modem off

[AMG]

I am working on a program that uses both CoAP and GPS in the form of thread. Since both CoAP and GPS uses the modem, I have to turn it off so the other thread can use it. Working on v1.2.0 I can use these functions : 

 

lte_lc_power_off();
lte_lc_offline();
lte_lc_deinit();

 

Which works on v1.2.0. But since I am using v1.3.1 , the first two functions give an error and the third function (deinit) is removed in v.1.3.1. To summarize I am looking for a way to turn off the modem in v1.3.1.

[Håkon Alseth]

Hi,

 

Those calls issue AT+CFUN=0, then immediately sets the modem back in AT+CFUN=4 state, and again back to AT+CFUN=0.

Running only one of these will be sufficient.

Kind regards,

Håkon

[AMG]

I understand that. My issue is that on v1.3.1 the calls don't for some reason while they work on v1.2.0. So, currently I am looking for alternatives.

[Håkon Alseth]

What is the error that you observe? Does it return an error code or does it hang? Does the program run as expected until you run into this routine?

 

All these calls use the at_cmd library. Is that enabled?

[AMG]

Yes, at_cmd lib is included. The program runs as expected until the modem is being initialized once again for CoAP and then it hang. I  am also looking into into the possibility of it being a socket problem as well. Will do a bit more testing and will update after I know some more.    

[AMG]

Håkon Alseth The problem lies with lte_lc_init() after the modem is powered off. 

int err = lte_lc_init();
    if (err != 0) {
        printf("lte_lc_init failed: %d\n", err);
        return;
    }

Which gives :    lte_lc_init failed: -120

[Håkon Alseth]

Hi,

 

120 when using newlib is this errno:

https://github.com/eblot/newlib/blob/master/newlib/libc/include/sys/errno.h#L151

 

This is expected, as you unfortunately cannot de-init the lte_lc library with ncs v1.3.0:

https://github.com/nrfconnect/sdk-nrf/blob/v1.3.2/lib/lte_link_control/lte_lc.c#L493-L495

You can handle this by checking if ret == -EALREADY, and continue with the rest of your setup.

Note: The _deinit function is present in newer versions of ncs again:

https://github.com/nrfconnect/sdk-nrf/blob/v1.5.0/lib/lte_link_control/lte_lc.c#L795

 

Kind regards,

Håkon