Unable to change the serial LTE modem baudrate

RE: Unable to change the serial LTE modem baudrate

Larry — Thu, 18 Jun 2020 07:15:22 GMT

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

RE: Unable to change the serial LTE modem baudrate

kk2mkk — Thu, 18 Jun 2020 05:56:56 GMT

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.

[quote userid="82276" url="~/f/nordic-q-a/62658/unable-to-change-the-serial-lte-modem-baudrate/255590"]What do you mean by "it has no effect"? [/quote]

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>;
};

[quote userid="82276" url="~/f/nordic-q-a/62658/unable-to-change-the-serial-lte-modem-baudrate/255590"]To check if it has an effect, open up serial_lte_modem/build_folder/spm/zephyr/zpehyr.dts after building and read out [/quote]

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

RE: Unable to change the serial LTE modem baudrate

Heidi — Wed, 17 Jun 2020 14:59:08 GMT

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