using nRF9160 SLM

[sravan.rikka]

Hi Team,

Can you please provide your inputs here.

1. Is the nRF9160 SLM supports NIDD(non-ip data delivery)? If yes, can you please provide the AT commands to configure NIDD.

2. Is the  nRF9160 SLM MQTT supports TLS?

3. We have tried  nRF9160 SLM FOTA on nRF9160 DK board, it seems that FOTA upgrade is happening on external Flash and in next power cycle it is copying from external Flash to internal Flash. Is that my understanding correct? Is the external Flash is mandatory for the FOTA? Can't we upgrade the internal Flash directly through FOTA?

Regards,

Sravan Rikka

[Charlie]

Hi Sravan,

1. The answer is no. It is not a standard AT command. You can refer to sample Cellular: NIDD — nRF Connect SDK 2.6.0 documentation (nordicsemi.com). It may be possible to set NIDD using the APN and Sockets commands.

2. Yes, it is possible. MQTT connect #XMQTTCON command can specific the port and sec_tag. You need to write TLS credentials into assigned sec_tag, which can refer to the following guidance.

Automating nRF91 TLS credential management via serial port AT commands - Software and Protocols - Cellular IoT guides - Nordic DevZone (nordicsemi.com)

3. In SLM application, external flash is used only when you need full modem support in FOTA request #XFOTA.

3 - Start FOTA for full modem update. Can only be used when the overlay-full_fota.conf configuration file is used.

This is due to an external flash memory with minimum 4 MB of free space is required to perform a full modem update. For your full application FOTA, it is OK as long as it is smaller than partition limitation(447.5KB for SLM).

Best regards,

Charlie

[sravan.rikka]

Thank you for the response.

1. In nRF9160 SLM case, we have to use AT commands to interact with nRF9160 SLM, correct? So, using APN and socket commands we can configure NIDD in nRF9160 SLM?

3. I am not using full modem(3 - Start FOTA for full modem update) update option, I am using op=1 (1 - Start FOTA for application update). In this op=1 case, is the FOTA will update in internal Flash?

AT#XFOTA=<op>[,<file_url>[,<sec_tag>[,<pdn_id>]]]

[Charlie]

Hi Sravan,

1. You can refer to SLM document page Application description — nRF Connect SDK 2.6.0 documentation (nordicsemi.com), it provides a sample configuration for NIDD connection in the slm_auto_connect.h file.

2. Yes. You can search "flash_dev" which is the external flash device name in SLM source codes. It is only used when CONFIG_SLM_FULL_FOTA is set.

Best regards,

Charlie

[sravan.rikka]

1. So, you are saying that NIDD enable is possible in SLM.

[Charlie]

Yes, did you see the following content in the page I point to?

Here is a sample configuration for NIDD connection in the slm_auto_connect.h file:

/* Network-specific default system mode configured by %XSYSTEMMODE (refer to AT command manual) */
0,        /* LTE support */
1,        /* NB-IoT support */
0,        /* GNSS support, also define CONFIG_MODEM_ANTENNA if not Nordic DK */
0,        /* LTE preference */
/* Network-specific default PDN configured by +CGDCONT and +CGAUTH (refer to AT command manual) */
true,     /* PDP context definition required or not */
"Non-IP", /* PDP type: "IP", "IPV6", "IPV4V6", "Non-IP" */
"",       /* Access point name */
0,        /* PDP authentication protocol: 0(None), 1(PAP), 2(CHAP) */
"",       /* PDN connection authentication username */
""        /* PDN connection authentication password */

[sravan.rikka]

Hi Charlie,

Yes, I have seen that content but in AT command manual I couldn't see the pdp_type option as "Non-IP". Can you please share the latest AT command manual.

As I understood that it is a string, so I can write string as "Non-IP" then it will be configured as NIDD, am I correct?

[Charlie]

Here you can find the latest AT Commands document https://docs.nordicsemi.com/bundle/ref_at_commands/page/REF/at_commands/packet_domain/cgdcont_set.html

Yes, your understanding is correct.