I face the following issue. I connected my RasPi (3b) with an Arduino Uno via RX/TX and a logic level converter. UART comms from the RasPi to the Arduino and vice-versa work fine on minicom and serial monitor. It also works fine from my qt program to the serial monitor, but as soon as I start a Serial.begin(9600,8N1) or Serial.begin(9600) function on the Arduino there seems to be no communication anymore at all between the two. Neither the expected result (toggle an LED, works from serial monitor), nor any blinking of the tx/ex LEDs onboard anymore. Issue occurs no matter if I provide power to the Arduino via USB or the 9v powercable. Any suggestions?