card5:
Yeah so it's FTDI indeed.Another interesting that I noticed, is that:
If I first connect the FTDI board to the USB, and only after that connect the wires from the FTDI to the Pro Mini,
then the problem happens.If I connect the other way:
First the wires from the FTDI board, to the Pro Mini (while the FTDI board is not connected to USB)
and only then connect the FTDI to USB, then it works OK.Maybe the problem never happens to you, because of the way you connect?
Could be:
a) A decoupling problem - try adding an extra capacitor on the FTDI board.
b) A problem with the order in which the pins connect. Try making the Vcc and GND pins a bit longer so they always connect first (ie. make all the other pins a bit shorter...)