Often the Transmit and Receive pins are labeled relative to the board they are on. The Transmit of one board should go to the Receive of the other board and vice-versa.You should be able to determine which processor you have (168 vs 328) by looking at the chip markings.You should be able to measure the CPU voltage(3.3V vs 5V) with a multimeter or look at the markings on the voltage regulator.
So it is a standard behavior with other FTDI boards?
Is the eBay cheapie an FTDI chip, or the other ones? (CP2102 or PL2303 ones)
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?
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...)
Quote from: fungus on May 23, 2013, 09:48 ama) A decoupling problem - try adding an extra capacitor on the FTDI board.Where should I put it? between which 2 legs/contacts?
It's interesting:Why should it affect?What's the problem in having the data legs connected first, and only int he end the 2 Vcc+Gnd legs?