Can not config UART 1, if using UART 2 or 3 the program works fine

[ZORK007]

Hey all,

I have started working with this board around a month ago, and start to understand it little by little. I have a program that communicates with a display over UART. It works well when it is configured with UART 2 or 3. But when I try to configure with UART 1 it does not work. I did some reading on the forum and I found that you should add CONFIG_BSD_LIBRARY_TRACE_ENABLED=n in prj.conf but this also did nothing.  So I would have just used UART 2 or 3 for the display, but this is also not an option because I have two other devices that use UART. And need 3 UART for the final system. The config file and overlay file are listed beneath. (UART 2 and 3 are config the same but I just change the number). Do you maybe know how to configure UART 1, or what I am doing wrong? NCS version: 1.3.0, Board: nrf9160dk_nrf9160 and I use SES V4.52.

.prj file:

CONFIG_SERIAL=y
CONFIG_UART_INTERRUPT_DRIVEN=y

CONFIG_SPI_1=n
CONFIG_I2C_1=n

overlay file:

&uart1 {
    current-speed = <57600>;
    status = "okay";
    tx-pin = <19>;
    rx-pin = <17>;
    rts-pin = <0xFFFFFFFF>;
    cts-pin = <0xFFFFFFFF>;
};

Thanks in advance for your time

[Susheel Nuguru]

Most likely the logs are using UART1?

Make sure you use RTT instead of UART for logs so that you have UART available for display

CONFIG_USE_SEGGER_RTT=y

CONFIG_LOG=y

CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_PRINTK=n

[ZORK007]

Dear Susheel,

Thank you for your reply. I added your config to my prj file. But how do I check if it uses UART of RTT for log?

[Susheel Nuguru]

If you open the RTT Viewer, then you should be getting the logs redirected to this viewer instead of any uart terminal viewer. When you open the UART terminal viewer, you should not see any logs in it, then you know that UART is free to use for other connections-

[ZORK007]

Thanks again for your reply, you are a great help. If that is the case, it is definitely was still using UART to log because RTT viewer didn't receive anything. After adding some lines to config, it is using RTT now. But UART 1 still does not receive any data from the sensor(Plugged sensor in so I could easily see if it is working or not, instead of display). What am I doing wrong?

My config file is right now:

CONFIG_SERIAL=y
CONFIG_UART_INTERRUPT_DRIVEN=y

CONFIG_SPI_1=n
CONFIG_I2C_1=n


CONFIG_TRUSTED_EXECUTION_NONSECURE=y

CONFIG_PRINTK=y
CONFIG_CONSOLE=y
CONFIG_STDOUT_CONSOLE=y

CONFIG_UART_CONSOLE=n
CONFIG_RTT_CONSOLE=y

CONFIG_USE_SEGGER_RTT=y

CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_PRINTK=n

and overlay file:

&uart1 {
    current-speed = <9600>;
    status = "okay";
    tx-pin = <0xFFFFFFFF>;
    rx-pin = <17>;
    rts-pin = <0xFFFFFFFF>;
    cts-pin = <0xFFFFFFFF>;    
};

[ZORK007]

Do you happen to know why it is still not working?

[Susheel Nuguru]

have you enabled anyother serial device instance1? 

i can see that you set SPI1 and I2C1 as not set, but what about TWI1? I cannot see anyother reason why this does not work.