Connecting to MQTT broker using NRF5340 with NRF9161 setup as SLM

RE: Connecting to MQTT broker using NRF5340 with NRF9161 setup as SLM

AdrianT — Wed, 18 Sep 2024 13:19:19 GMT

Yes that is correct.

RE: Connecting to MQTT broker using NRF5340 with NRF9161 setup as SLM

Charlie — Wed, 18 Sep 2024 13:09:12 GMT

Never tried, but I believe it is possible.

I assume you want to run MQTT protocol stack on nRF5340, then you can use TCP socket from SLM with TLS supported.

RE: Connecting to MQTT broker using NRF5340 with NRF9161 setup as SLM

AdrianT — Wed, 18 Sep 2024 12:56:33 GMT

Thanks for the response.

I am using the mqtt subystem in zephyr - thus, I am not directly using the AT Commands that you gave. Instead, I am calling mqtt_connect() function with the corresponding configurations populated in mqtt_client struct (in mqtt.h file).

Is this still applicable?

RE: Connecting to MQTT broker using NRF5340 with NRF9161 setup as SLM

Charlie — Wed, 18 Sep 2024 12:48:41 GMT

Hi AdrianT,

You can still use secure connection, as long as your nRF9161 has certificates in the pointed sec_tag. It does not matter which command host you are using.

See MQTT client AT commands (nordicsemi.com):

AT#XMQTTCON=<op>[,<username>,<password>,<url>,<port>[,<sec_tag>]]

The <op> parameter is an integer. It can accept one of the following values:
- 0 - Disconnect from the MQTT broker.
- 1 - Connect to the MQTT broker using IP protocol family version 4.
- 2 - Connect to the MQTT broker using IP protocol family version 6.
The <username> parameter is a string. It indicates the MQTT client username.
The <password> parameter is a string. It indicates the MQTT client password in cleartext.
The <url> parameter is a string. It indicates the MQTT broker hostname.
The <port> parameter is an unsigned 16-bit integer (0 - 65535). It indicates the MQTT broker port.
The <sec_tag> parameter is an integer. It indicates the credential of the security tag used for establishing a secure connection.

Try to play this sample with Serial Terminal first to try MQTT TLS connection and you can refer to the following discussion.

(+) Are there any examples out there for a host application in C that is using AT commands via serial to the nRF9160 running the Serial LTE Modem for a MQTT TLS connection? - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

Best regards,

Charlie