nRF9160 SLM with Zephyr native_sim on linux

[Pafka]

Hi,

We develop functionalities on native_sim before moving to embedded, therefore I am trying to have nRF9160 modem connected to Zephyr "cellular_modem" sample on linux native_sim.

I compiled "serial_lte_modem" with "west build -b nrf9160dk/nrf9160/ns -p -- -DEXTRA_CONF_FILE=overlay-ppp-cmux-linux.conf && west flash" (v3.0.2). I had to remove "hw-flow-control" on uart0 to have the communication. The modem is connected to developer's PC with USB (nRF9160 DK board). It answers communication, connects to APN - all OK.

The "cellular_modem" sample is from Zephyr source (not nrf, although diff does not show differences related to the issue). This native_sim app, uses DTS uart_1 as "zephyr,native-pty-uart" with modem on it and uart_1 is showing as PTY on linux.

/ {
	aliases {
		modem = &modem;
	};

	chosen {
		zephyr,console = &uart0;
		zephyr,shell-uart = &uart0;
	};

	uart_1: uart_1 {
		compatible = "zephyr,native-pty-uart";
		current-speed = <115200>;
		status = "okay";

		modem: modem {
			compatible = "nordic,nrf91-slm";
			status = "okay";
		};
	};
};

The uart_1 where the app is run is then connected with socat to /dev/ACM0. Communication starts, I get AT commands running, but just when CMUX is enabled with AT#XCMUX=1 it stops. No output from app nor from the SLM modem. 

Log from console of the cellular_modem app:

uart connected to pseudotty: /dev/pts/6
uart_1 connected to pseudotty: /dev/pts/7
*** Booting Zephyr OS build v4.1.0-5405-ge571f8bab428 ***
Powering on modem
[00:00:05.010,000] <dbg> modem_cellular: modem_cellular_log_event: event resume
[00:00:05.010,000] <dbg> modem_cellular: modem_cellular_log_state_changed: switch from idle to run init script
[00:00:05.010,000] <dbg> modem_cellular: modem_cellular_log_event: event bus opened
[00:00:05.010,000] <dbg> modem_chat: modem_chat_script_start: running script: nordic_nrf91_slm_init_chat_script
[00:00:05.010,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 0
[00:00:05.010,000] <dbg> modem_chat: modem_chat_script_next: sending: AT
Bring up network interface
Waiting for L4 connected
[00:00:05.070,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.070,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 1
[00:00:05.070,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CFUN=0
[00:00:05.150,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.150,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 2
[00:00:05.150,000] <dbg> modem_chat: modem_chat_script_next: sending: AT%XSYSTEMMODE=1,0,0,0
[00:00:05.210,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.210,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 3
[00:00:05.210,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CFUN=0
[00:00:05.450,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.450,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 4
[00:00:05.450,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CEREG=1
[00:00:05.510,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.510,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 5
[00:00:05.510,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CFUN=1
[00:00:05.610,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.610,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 6
[00:00:05.610,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CMEE=1
[00:00:05.670,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.670,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 7
[00:00:05.670,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CEREG=1
[00:00:05.730,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.730,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 8
[00:00:05.730,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CEREG?
[00:00:05.790,000] <dbg> modem_chat: modem_chat_log_received_command: +CEREG:  1 4
[00:00:05.790,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.790,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 9
[00:00:05.790,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CGSN
[00:00:05.790,000] <dbg> modem_cellular: modem_cellular_log_event: event deregistered
[00:00:05.850,000] <dbg> modem_chat: modem_chat_log_received_command:  351516172759573
[00:00:05.850,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 10
[00:00:05.850,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.850,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 11
[00:00:05.850,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CGMM
[00:00:05.910,000] <dbg> modem_chat: modem_chat_log_received_command:  nRF9160-SICA
[00:00:05.910,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 12
[00:00:05.910,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.910,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 13
[00:00:05.910,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CGMI
[00:00:05.970,000] <dbg> modem_chat: modem_chat_log_received_command:  Nordic Semiconductor ASA
[00:00:05.970,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 14
[00:00:05.970,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:05.970,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 15
[00:00:05.970,000] <dbg> modem_chat: modem_chat_script_next: sending: AT+CGMR
[00:00:06.030,000] <dbg> modem_chat: modem_chat_log_received_command:  mfw_nrf9160_1.3.5
[00:00:06.030,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 16
[00:00:06.030,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:06.030,000] <dbg> modem_chat: modem_chat_script_next: nordic_nrf91_slm_init_chat_script: step: 17
[00:00:06.030,000] <dbg> modem_chat: modem_chat_script_next: sending: AT#XCMUX=1
[00:00:06.090,000] <dbg> modem_chat: modem_chat_log_received_command: OK
[00:00:06.090,000] <dbg> modem_chat: modem_chat_script_stop: nordic_nrf91_slm_init_chat_script: complete
[00:00:06.090,000] <dbg> modem_cellular: modem_cellular_log_event: event script success

(there is 5s delay on start, to allow me to run socat on other terminal)

socat starts with:

socat -v /dev/ttyACM0,raw,echo=0,b115200 /dev/pts/7,raw,echo=0

and shows AT commands and responses (no issues spotted).

Would be grateful for any idea.

Regards

[Håkon Alseth]

Hi,

 

What is your current slm build configuration? Note that linux vs. zephyr modem compliant differs in terms of .conf files:

https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/applications/serial_lte_modem/doc/nRF91_as_Zephyr_modem.html#nrf91_series_sip_running_slm

 

Based on the log, it seems to run, but not answer.

Is the problem that it is encoding your line-ending in addition to the "AT"?

[00:00:10.790,000] <dbg> modem_cmux: modem_cmux_log_frame: data:
                                     41 54                                            |AT               
[00:00:10.790,000] <dbg> modem_cmux: modem_cmux_log_frame: tx ch:1 cr:1 pf:0 type:UIH dlen:2
[00:00:10.790,000] <dbg> modem_cmux: modem_cmux_log_frame: data:
                                     0d 0a                                            |..               
[00:00:10.790,000] <dbg> modem_cmux: modem_cmux_transmit_handler: About to transmit to UART:
                                     f9 07 ef 05 41 54 30 f9  f9 07 ef 05 0d 0a 30 f9 |....AT0. ......0.

Pafka said:

PS. Does the Zephyr cellular_modem works with SLM as described here: https://docs.nordicsemi.com/bundle/ncs-2.6.1/page/nrf/applications/serial_lte_modem/doc/nRF91_as_Zephyr_modem.html#slm-as-zephyr-modem "out of the box"?

With additional configuration(s), yes, that is the intention.

 

Kind regards,

Håkon

[Pafka]

Håkon Alseth said:

With additional configuration(s), yes, that is the intention.

Can you disclose the configuration?

[Håkon Alseth]

Hi,

 

They are listed in the docs:

https://docs.nordicsemi.com/bundle/ncs-2.6.1/page/nrf/applications/serial_lte_modem/doc/nRF91_as_Zephyr_modem.html#nrf91_series_sip_running_slm

 

Kind regards,

Håkon