How to use 1M UART in nRF5340 DK board

[JIYEON]

Hello,

I want to use 1M baud rate in nRF5340 DK board.

DK board is connected to USB to Serial.

Until 921600, UART is received correctly. And UART is broken in 1M.

What I did is change DT_N_S_soc_S_peripheral_50000000_S_uart_8000_P_current_speed.

#define DT_N_S_soc_S_peripheral_50000000_S_uart_8000_P_current_speed 1000000//921600

In datasheet, I found that "High baud rates may require GPIOs to be set as High Drive, see GPIO chapter for more details."

How could I do this?

[Øivind]

Hi,

Try changing the property using an overlay file instead. The overlay file should contain something like this:

&uart0 {
    current-speed = <1000000>;
};

[JIYEON]

Hi,

I followed this link to create overlay file.

https://devzone.nordicsemi.com/f/nordic-q-a/81140/can-t-open-overlay-file-in-segger

But it doesn't work.

What I add to overlay is

&uart0 {
 current-speed = <1000000>;
 tx-pin = <20>;
 rx-pin = <22>;
 rts-pin = <19>;
 cts-pin = <21>;
};

[Øivind]

Ok,

The overlay file should have the same name as your board, and be placed in the project folder.
When you build the project, there should be a line near the top of the build log similar to:
"Using overlay file: nrf5340dk_nrf5340_cpuapp.overlay"

Did you remember to remove the previous changes you made while trying to set the speed to 1000000?
If not, try that.

Make sure that you re-open the project in SES, or click Project->Run CMake after making changes to overlay files or prj.conf.

Also make sure that the other end, terminal on connected computer for example, is also set up for 1000000 baud rate.