no output on RTT viewer using zephyr

[villa_dev]

Hello,

I am beginner with Zephyr and for sure i have problems. I am trying to make simple app in order to get "hello World" via RTT viewer without success. I have read a lot of cases with similar problems and i have tested all solutions but no way.

I am using PCB MDK dongle with nrf52840 assembled (https://wiki.makerdiary.com/nrf52840-mdk-usb-dongle/). I have access to pins SWD (RST, SWDCLK and SWDIO, but SWO is not HW mapped). I could flash the PCB without problems using external J-Link and RTT viewer is conneted correctly but once APP is running there is no output in the terminal.

RTT viewer version 7.80C

Zephyr version 3.2.99

prj.conf is

# nothing here

CONFIG_PRINTK=y

CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=n
CONFIG_RTT_CONSOLE=y
# Enable RTT
CONFIG_USE_SEGGER_RTT=y

CONFIG_LOG=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_PRINTK=y

source:

#include <zephyr/kernel.h>
#include <zephyr/sys/printk.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(main);

void main(void)
{
	while (1){
		printk("Test printk\n");
		k_sleep(K_SECONDS(1));
		LOG_INF("Info message example.");
		k_sleep(K_SECONDS(1));
	}
}

Could any body help me, please?

Thanks in advance!

[villa_dev]

I have erased the MCU via J-Flash Lite Segger tool and after flash again application, problem is still present no output in RTT viewer (MCU is detected correctly by RTT viewer but no data in terminal), it does not seem that MCUboot is present because does not enter in DFU mode as it happened before erase. Anybody have more ideas?I am realy tired with this issue.