at_cmd_mode AT+CFUN=4 problem on modem_shell firmware

[Oguzhan Turk]

On modem_shell firmware, after entering into at_cmd_mode (at at_cmd_mode start), any AT command works fine but AT+CFUN=4 (offline) command blocks the terminal and doesn't respond back with any upcoming at command anymore. Only solution is resetting modem and entering at_cmd_mode again but it's not a proper solution. Why does it stuck on offline command?

By the way, without entering at_cmd_mode, just calling offline command on mosh directly (at AT+CFUN=4) doesn't cause any problem. The problem is only on at_cmd_mode.

[Didrik Rokhaug]

Hi Oguzhan Turk,

I am not able to reproduce this.

Could you take a modem trace, so we can see if the problem is on the modem side?

I've attached a version of the modem shell, built for the nRF9160 DK, with modem tracing enabled.

Before you send the AT+CFUN=4 command, please send AT%XMODEMTRACE=1,2 to ensure that the modem has tracing enabled.

mosh_mtrace.hex

Best regards,

Didrik

[Oguzhan Turk]

By the way, I'm using development kit www.nordicsemi.com/.../nRF9160-DK

[Didrik Rokhaug]

Oguzhan Turk said:

I executed AT%XMODEMTRACE=1,2 and it returned OK and then I executed AT+CFUN=4. It stucked again and didn't produce any extra output for tracing.

Was CONFIG_NRF_MODEM_LIB_TRACE enabled?

Also, the modem trace is outputted on a separate COM port, it will not add more output from the application itself.

Oguzhan Turk said:

I also tried your mosh_mtrace.hex but it didn't work on my dev board. Instead of proper mosh outputs it put non-human readable characters to the screen like that:

What baudrate did you use?

The .hex file works as expected on my DK.

The shell interface is sent on one COM port, with a baudrate of 115200. The modem trace is sent on a different COM port, with baudrate 1000000, but it is not human readable anyway. Instead, you should use the Cellular Monitor in nRF Connect for Desktop to receive the trace and save it to disk. Then you can send me the .mtrace file.

(note that the COM port will probably be different in your case. The Cellular Monitor should be able to select the correct one automatically)