Migrating MQTT Sample to a Custom Board

[RodWatt]

Hi,

I have successfully built and ran the MQTT sample (/opt/nordic/ncs/v2.7.0/nrf/samples/net/mqtt) on the nRF9160-DK. I did have a few problems with SIM coverage and firmware versions which was sorted in this ticket.

 MQTT Sample Not Connecting on nRF9160 Board 

I would now like to move this code onto my own board.

When I run this code on my own board, I see this error.

*** Booting nRF Connect SDK v2.7.0-5cb85570ca43 ***
*** Using Zephyr OS v3.6.99-100befc70c74 ***
[00:00:00.431,610] <inf> network: Bringing network interface up and connecting to the network
[00:00:00.658,813] <inf> nrf_modem_lib_trace: Trace thread ready
[00:00:00.666,107] <inf> nrf_modem_lib_trace: Trace level override: 2
[00:00:00.667,724] <err> lte_lc: Could not send AT command, error: 65536
[00:00:00.667,755] <err> lte_lc: Failed to set system mode and mode preference, err -14
+CEREG: 2
+CEREG: 4
+CEREG: 2,"B984","00542616",9
+CSCON: 1
+CEREG: 2,"B984","00542616",9,0,11
+CSCON: 0

 

My overlay file is shown below.

&pinctrl {
        uart0_default: uart0_default {
                group1 {
                        psels = <NRF_PSEL(UART_TX, 0, 6)>, <NRF_PSEL(UART_RX, 0, 7)>;
                };
        };

        uart0_sleep: uart0_sleep {
                group1 {
                        psels = <NRF_PSEL(UART_TX, 0, 6)>, <NRF_PSEL(UART_RX, 0, 7)>;
                        low-power-enable;
                };
        };
};

&uart0 {
        status = "okay";
        current-speed = < 115200 >;
        /delete-property/ rts-pin;
        /delete-property/ cts-pin;
};

/* Enable uart1 for tracing. */

&uart1 {
   status = "okay";
   current-speed = <1000000>;
   pinctrl-0 = <&uart1_default>;
   pinctrl-1 = <&uart1_sleep>;
   pinctrl-names = "default", "sleep";
};

/ {
   chosen {
      nordic,modem-trace-uart = &uart1;
   };
};

I use UART0 for my serial terminal.

Would appreciate your pointers on this,

Thanks,

Rod 

[Charlie]

Hi Rod,

Did you manage to collect a modem trace through either uart1 or RTT terminal?

I see you also play with link monitor before. If this is a new custom board, are you able to see it can successfully connect with network when you check with link monitor after programming Serial LTE modem (nordicsemi.com)?

Best regards,

Charlie

[RodWatt]

Hi Charlie,

No, I didn't manage to get the trace to work.

I tried the serial LTE example,

/ {
	chosen {
		ncs,slm-uart = &uart1;
	};
};

&uart0 {
	status = "okay";
	hw-flow-control;
};

&uart1 {
	compatible = "nordic,nrf-uarte";
	current-speed = <115200>;
	status = "okay";

	pinctrl-0 = <&uart1_default_alt>;
	pinctrl-1 = <&uart1_sleep_alt>;
	pinctrl-names = "default", "sleep";
};



&i2c2 {
	status = "disabled";
};

&pinctrl {
	uart1_default_alt: uart1_default_alt {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 7)>;
			bias-pull-up;
		};
		group2 {
			psels = <NRF_PSEL(UART_TX, 0, 6)>;
		};
	};

	uart1_sleep_alt: uart1_sleep_alt {
		group1 {
			psels = <NRF_PSEL(UART_TX, 0, 6)>,
				<NRF_PSEL(UART_RX, 0, 7)>;
			low-power-enable;
		};
	};
};

I am using my own overlay file, above to redirect the serial. terminal.

Im getting this as an output

All pins have been configured as non-secure
[Sec Thread] Secure image initializing!
TF-M Float ABI: Hard
Lazy stacking enabled
Booting TF-M v2.0.0-ncs2
Ready

Rod

[dejans]

Hi Rod,

Here are some discussions related to the same/similar problem:
- LTE LC cannot send AT commands
- error switching LTE to LTE GPS
- lte_lc_func_mode_set() fails
- fatal error using NB-IoT with GNSS

Regarding modem trace, you can find more information in Debugging with modem trace. Sending traces over RTT needs to be enabled using CONFIG_NRF_MODEM_LIB_TRACE_BACKEND_RTT.

I hope that at least some of above-mentioned links can be helpful to you.

Best regards,
Dejan

[RodWatt]

Hi Dejan,

I started again with a clean build, refreshed modem firmware etc. I also enabled the RTS/CTS signals on the trace port and am now seeing some traces.

6811.test.pcapng

Regards,

Rod

[dejans]

Hi Rod,

Do you still get the same error in the application log (shown below)?

<err> lte_lc: Could not send AT command, error: 65536
<err> lte_lc: Failed to set system mode and mode preference, err -14

If there is any difference, please provide new application log.

Best regards,
Dejan

[RodWatt]

Hi Dejan,

Yes, still getting the same error.

*** Booting nRF Connect SDK v2.7.0-5cb85570ca43 ***
*** Using ZK OS v3.6.99-100befc70c74 ***
[00:00:00.404,541] <ifrݽɭ: Bringing network interface up and connecting to the Sݽɭm[0m
[00:00:00.405,151] <dbg> mqtt_helper: mqtt_stae5: State transition: MQTT_STATE_UNINIT --> MQTT_STATE_DISCONECTED
[00:00:00.435,607] <dbg> mqtt_helper: mqtt_helper_poll_loop:aiting for connection_poll_sem
[00:00:00.633,056] <i> nrf_modem_lib_trace: Trace thread ready
[00:00:00.640,3NW<inf> nrf_modem_lib_trace: Trace level override: 2
A҂҂r41,937] <err> lte_lc: Could not send AT command, error: 65536
[00:00:00.641,967] <err> lte_lc: Failed to set system mode and mode preference, err -14

Regards, Rod

[dejans]

Hi Rod,

What is your current modem firmware version?

When I compare your trace file with the trace file for nrf9160-dk, there seem to be no connection procedure or attachment attempt in your log. Can you take a longer modem trace which would potentially show that?

Best regards,
Dejan

[RodWatt]

Hi Dejan,

I am running the latest, 1.3.6.

Test-nov7.pcapng

Rod

[dejans]

Hi Rod,

I will look into this during next week.
I expect to get back to you by the end of next week.

Best regards,
Dejan

[dejans]

Hi Rod,

AT%XSYSTEMMODE command is allowed only before activating the modem using AT+CFUN=1. Before changing the system mode, you could try to put the modem in a required state using AT+CFUN=0 (or AT+CFUN=4).

Best regards,
Dejan 

[RodWatt]

Hi Dejan,

I am running the "standard mqtt sample", (nrf/samples/net/mqtt) unmodified; so have not touched the code. It runs fine on the nRF9160DK board. 

I tried another one of my boards and it seems to work, although I cant see any traces on the UART on the second board. This is what I see on the serial terminal.

[00:00:00.721,435] <inf> nrf_modem_lib_trace: Trace thread ready
[00:00:00.722,595] <inf> nrf_modem_lib_trace: Trace level override: 2
[00:00:00.724,426] <err> lte_lc: Could not send AT command, error: 65536
[00:00:00.724,456] <err> lte_lc: Failed to set system mode and mode preference, err -14
[00:00:02.118,682] <wrn> nrf_modem_lib_netif: lte_lc_modem_events_enable, error: -14
+CEREG: 2,"01B0","0928D982",7,0,0,"11100000","11100000"
[00:00:16.853,210] <wrn> lte_lc: Registration rejected, EMM cause: 0, Cell ID: 153672066, Tracking area: 432, LTE mode: 7
+CSCON: 1
+CGEV: ME PDN ACT 0,0
+CNEC_ESM: 50,0
+CEREG: 1,"01B0","0928D982",7,,,"11100000","11100000"
[00:00:19.289,672] <inf> network: Network connectivity established
+CSCON: 0
+CSCON: 1
+CSCON: 0
+CSCON: 1
[00:00:45.602,630] <inf> transport: Connected to MQTT broker
[00:00:45.602,691] <inf> transport: Hostname: test.mosquitto.org
[00:00:45.602,722] <inf> transport: Client ID: 352656100493439
[00:00:45.602,722] <inf> transport: Port: 8883
[00:00:45.602,752] <inf> transport: TLS: Yes
[00:00:45.602,813] <inf> transport: Subscribing to: 352656100493439/my/subscribe/topic
[00:00:46.262,634] <inf> transport: Subscribed to topic 352656100493439/my/subscribe/topic
[00:00:46.606,658] <inf> transport: Published message: "Hello MQTT! Current uptime is: 46605" on topic: "352656100493439/my/publish/topic"
[00:00:46.627,716] <inf> transport: Published message: "Hello MQTT! Current uptime is: 46626" on topic: "352656100493439/my/publish/topic"
[00:00:46.640,441] <inf> transport: Published message: "Hello MQTT! Current uptime is: 46639" on topic: "352656100493439/my/publish/topic"
[00:00:46.653,015] <inf> transport: Published message: "Hello MQTT! Current uptime is: 46651" on topic: "352656100493439/my/publish/topic"
[00:00:46.664,398] <inf> transport: Published message: "Hello MQTT! Current uptime is: 46663" on topic: "352656100493439/my/publish/topic"

So, summarise.

When i run the code on one of my boards, i get a trace on UART0 but the board does not connect to the network.

When i run the same code on another board, (exact same hardware, same code, same SIM card etc). It does connect but I do not see a trace. 

I have flashed both boards with the latest modem firmware. 

Apart from the possibility of a hardware fault, is there anything else i am missing?

Thanks,

Rod