How to Separate Logging and Serial Communication on Different VCOMs (nRF5340)

Question

I am using the board nRF5340 Soc , which by default exports two VCOM ports via the J-Link OB debugger . Currently: 
 
 VCOM1 (UART0) is used for both logging and serial communication by default. 
 VCOM2 mainly logs boot information. 
 
 Goal: 
 I want to separate logging and serial communication as follows: 
 
 VCOM1 (UART0) → Only for logs (debug messages). 
 VCOM2 (UART1) → Only for serial read/write communication. 
 
 Questions: 
 
 Is there an internal J-Link OB forwarding mechanism that could be causing this issue? 
 Are there any Zephyr configurations or Nordic-specific settings required to properly separate logs and serial communication? 
 What is the best way to ensure logs stay on VCOM1 and serial communication happens only on VCOM2 ? 
 
 Any guidance or recommendations would be greatly appreciated. Thanks!

Edvin · Accepted Answer

Both. Sorry for being a bit short in my previous reply. I didn't have time to look up all the configs. But again, if this is only for development, save yourself some time and use RTT Logging. Yash48 said: Disabling Network Core Logging & Stopping Pin Forwarding Yash48 said: Should I modify the .overlay file, prj.conf , or both? Both. .overlay to disable and enable the correct UARTs, and Kconfig (prj.conf) to enable disable logging. Yash48 said: How should I configure the .overlay file and prj.conf to ensure logs stay on UARTE0 while UART1 is used solely for communication? UARTE0 will be used for logging. I don't remember exactly which setting it is, but it is the one linked to console in the board files (nrf5340dk_nrf5340.dts/dtsi). Yash48 said: Should I modify the zephyr,console or zephyr,shell-uart settings? console. Yash48 said: What additional configurations (e.g., Kconfig, DTS) are needed to ensure UART1 does not interfere with VCOM2? you should never modify the dts/dtsi files directly. If you find something in these files that you want to change, copy that section, and paste it into .overlay, and edit it there. So, what you actually need to do. If you look in nrf5340_cpuapp_common.dtsi: / { chosen { zephyr,console = &uart0; zephyr,shell-uart = &uart0; zephyr,uart-mcumgr = &uart0; zephyr,bt-mon-uart = &uart0; zephyr,bt-c2h-uart = &uart0; zephyr,bt-hci = &bt_hci_ipc0; nordic,802154-spinel-ipc = &ipc0; zephyr,ieee802154 = &ieee802154; }; Here you can see that the console is pointing to uart0, so whatever you configure as the UART0 pins will be the ones that will output the log messages. This is set in nrf5340_cpuapp_common-pinctrl.dtsi: &pinctrl { uart0_default: uart0_default { group1 { psels = , ; }; group2 { psels = , ; bias-pull-up; }; }; uart0_sleep: uart0_sleep { group1 { psels = , , , ; low-power-enable; }; }; }; Paste this snippet into your nrf5340dk_nrf5340_cpuapp.overlay if you want to change the pins. Also create this for uart1_default and uart1_sleep. To disable the GPIO forwarding, you need to add this line to your .overlay file:: /delete-node/ &gpio_fwd; Then set up uart0 and uart1 by enabling them in .overlay. The uart0 is enabled by default, but you can add uart1 like this: &uart1 { status = "okay"; current-speed = <115200>; pinctrl-0 = <&uart1_default>; pinctrl-1 = <&uart1_sleep>; pinctrl-names = "default", "sleep"; }; And you can add this snippet as well, so that you have something to point to in your application: / { chosen { nordic,app-uart = &uart1; }; }; And then you can use it in your application, pretty much like it is done in the NCS rf\samples\bluetooth\peripheral_uart, but in main.c, instead of: static const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(nordic_nus_uart)); you can use: static const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(nordic_app_uart)); You can call it whatever you like. It doesn't need to be "nordic,app-uart", but remember that all "-" and "," will be replaced with "_" in your .c files. Best regards, Edvin

How to Separate Logging and Serial Communication on Different VCOMs (nRF5340)

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