I want to debug my Arduino Pro Mini with the UART via the FTDI Basic Breakout. Now I have the problem that everytime I plug the USB connector with my pc the microcontroller creates a reset. If I open for example putty for displaying the uart data the microcontroller restarts again. Why?

How could I turn this "reset-feature" off??

Regards Sebastian

Are you connecting the DTR signal as well? Or just the RX and TX lines?

I connected all pins of the FTDI Breakout Board ( (Schematic: with the Arduino Pro Mini.

Whats the DTR pin doing?

If I disconnect it, the reset after programming flash doesn’t work anymore, or not?

The DTR pin connects via capacitor to the reset line. The IDE causes it to go low to reset the promini to start the download sequence. You can remove the capacitor on the promini (use a multimeter to ensure you remove the correct part) or remove the DTR pin from your promini header if that is how you connect the FTDI adapter; then you will have to press reset prior to programming (and after as well (?) to start your sketch.