No communication on linux UPDI with attiny 1616

[skorakora]

Completely no communication I have tried to eliminate everything. There is only short LOW pulse sent that lasts arround 90us It repeats 3 times. My command is: "pymcuprog ping -d attiny1616 -t uart -u /dev/ttyUSB0" response is: " Connecting to SerialUPDI pymcuprog.pymcuprog - ERROR - Operation failed with PymcuprogError: UPDI initialisation failed "

Problem is definitely on side of library, I read trough documentation, and this impulse will never initiate communication. uC is waiting for special sync character. This pulse is not even close to the sync character labeled in datasheet.