Serial LTE Modem + MQTT subscribe

RE: Serial LTE Modem + MQTT subscribe

Carl Richard — Fri, 15 Jan 2021 07:54:30 GMT

Hi!

My apologies. To use MQTT with SLM on v1.4.990-dev1 it must be configured by adding CONFIG_SLM_MQTTC=y in the prj.conf file. Just append it at the end.

The debug log of the Serial LTE Modem are written to RTT over the SWD interface, as the serial interface are used only for the modem functionality. To read the log you can use the Segger RTT Viewer program while your board is connected to the nRF9160DK board with JTAG. You can read more about how you can use the RTT viewer here.

Best regards,
Carl Richard

RE: Serial LTE Modem + MQTT subscribe

fe-hadella — Thu, 14 Jan 2021 23:47:48 GMT

Hello,

I tried out the v1.4.990-dev1 today. Commands like #XFTP and #XMQTTCON are now consistently just reporting ERROR which isn't helpful. In the last version v1.4.1, I noticed the connect command now required a username and password, so I added that. It would connect ok all the time.

I didn't notice any new characters when I enter commands with the CONFIG_SLM_LOG_LEVEL_DBG line. I can tell the modem version with AT+CGMR. Is there a command to get back the 1.4.99? I'm programming our boards nRF9160 via a JTAG using the debug out on the nRF9160-dk board.

RE: Serial LTE Modem + MQTT subscribe

Carl Richard — Thu, 14 Jan 2021 09:36:51 GMT

Hi again!

The SLM firmware has gotten quite a lot of updates in the master branch of NCS (v1.4.99-dev1), so I would recommend trying out that aswell.

As for the logging you can navigate to the serial LTE monitor project folder (should be located at <ncs_root>/nrf/applications/serial_lte_modem) and open the file prj.conf in a text editor. Find CONFIG_SLM_LOG_LEVEL_INF and replace it with CONFIG_SLM_LOG_LEVEL_DBG. Then you must rebuild the application. If you use Segger Embedded Studio the project must be reloaded before rebuilding.

Please inform me if you face any difficulities!

Best regards,
Carl Richard

RE: Serial LTE Modem + MQTT subscribe

fe-hadella — Thu, 14 Jan 2021 00:13:04 GMT

Hello,

I updated the serial LTE firmware to 1.4.1 and the modem firmware to 1.2.3. I still had the same successes and the same failures with this version.

I'm not that familiar with customizing the nRF9160 firmware. Where would I modify CONFIG_SLM_LOG_LEVEL_INF=y? I will do the mod and reflash the unit and report back any new info.

RE: Serial LTE Modem + MQTT subscribe

Carl Richard — Tue, 12 Jan 2021 10:05:11 GMT

Hi!

Thanks for reaching out. The "#XMQTTEVT: 9,0" response is a MQTT_EVT_PINGRESP event, originating from the connection regurarly pinging the broker. Hence, it should be unrelated to the issue you are facing. On that note, are you able to read out the log over the RTT interface? That could give more insight into what's actually happening. Please replace CONFIG_SLM_LOG_LEVEL_INF=y with CONFIG_SLM_LOG_LEVEL_DBG=y in the prj.conf.

I will report the JSON issue to the developers. What error are you getting?

Best regards,
Carl Richard