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,

Dejan has a sick leave recently. I will help you on this issue.

Modem trace configuration guidance is available in NCS document page: https://docs.nordicsemi.com/bundle/ncs-2.7.0/page/nrf/device_guides/nrf91/nrf91_features.html#modem_trace Please also make sure you are using the latest MFW v1.3.6.

Did you do any modification to the original mqtt sample? According to the following solutions for the same error, this issue is mostly due to incorrect firmware codes.
(+) Turn on and off modem - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

(+) [00:00:00.572,937] lte_lc: Could not send AT command, error: 65536 [00:00:00.572,967] lte_lc: Could not set system mode, error: -14 - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

Best regards,

Charlie

[RodWatt]

Hi Charlie,

Thanks for picking this up. Yes, i have the latest FW, to check, i have updated again.

15:38:09.198	Modem DFU starts to write...
15:38:09.198	Writing /Users/Watt/Downloads/mfw_nrf9160_1.3.6.zip to device 000601002540
15:38:41.022	Modem DFU completed successfully!

I have not modified the mqtt code, the only change is my overlay file shown above

Rod