Unable to change the serial LTE modem baudrate

[kk2mkk]

How do i change the baud rate for the serial LTE modem interface, changing the baudrate in the ~\ncs\v1.2.0\nrf\applications\serial_lte_modem\nrf9160dk_nrf9160ns.overlay has not effect :(

&uart2 {
    current-speed = <9600>;
    status = "okay";
    tx-pin = <10>;
    rx-pin = <11>;
    rts-pin = <12>;
    cts-pin = <13>;
};

regards

KK

[Heidi]

Hi!

What do you mean by "it has no effect"? 

Be aware that UART0 is logging to the COM port, not UART2 so if you're trying to read out the logging info at a 9600 baudrate, it will be illegible. 

To check if it has an effect, open up serial_lte_modem/build_folder/spm/zephyr/zpehyr.dts after building and read out current-speed under &uart2.

Best regards,

Heidi

[kk2mkk]

Hi Heidi,

UART0 is connected to usb-serial interface on the DK board which is used to send any AT command (in SLM app) from PC not for logging i guess.

Heidi said:

What do you mean by "it has no effect"? 

My problem is to communicate in lower baudrate like 9600 or 19200, so to achieve that i have made following changes in the .overlay file but still i cant communicate with the configured baudrate, am i missing something here?

&uart0 {
    current-speed = <9600>;
    status = "okay";
    tx-pin = <18>;
    rx-pin = <17>;
    rts-pin = <21>;
    cts-pin = <19>;
}; 

Heidi said:

To check if it has an effect, open up serial_lte_modem/build_folder/spm/zephyr/zpehyr.dts after building and read out

Yes i do see these changes reflecting in the zephyr.dts file, but cant communicate from PC to the DK board with the configured baudrate.

regards

KK

[Larry]

Hi KK,

Since you are using UART0, you can use original GPIO used for the UART connection:

&uart0 {

    current-speed = <9600>;
    status = "okay";
    tx-pin = <29>;
    rx-pin = <28>;
    rts-pin = <27>;
    cts-pin = <26>;
};

Best Regards,

Larry