Hallo I am building a standalone Arduino, following a combination of these two tutorials: http://www.arduino.cc/en/Main/Standalone and Julian Ilett's "1-Day Project" on youtube
The main difference being that Julian's dispenses with the reset button, due to the soft-reset function of the Sparkfun FTDI Basic board. The driver version from the FTDI site is 188.8.131.52.
I'm using an ATmega368-PU with Uno bootloader. Yesterday, I successfully built and programmed a standalone, with the DTR pin connected to the reset pin on the ATmega via a 100nf cap, and to VCC via 10K Ohm resistor. No hard reset was required and I uploaded several different sketches to the ATmega.
Using a second duplicate FTDI board (and ATmega) I tried to repeat the build and that's where everything went sour. My OS (Win 7 64-bit) refuses to let go of the COM port assigned to the first FTDI board. I cannot communicate with either of the ATmega328's now. In the Arduino IDE, the Serial Port option is greyed out, even with either FTDI board plugged in. When I unplug it, it's still there in my Device Manager. My own Mega2560 is working okay, and shows up (and disappears) from the Device Manager as expected, but I cannot get rid of "USB Serial Port". The only solution so far, is to restart my whole system, at which point the IDE shows the Serial Port again.
I strongly suspect the FTDI driver to be at fault here, and I'm asking if anyone has either had such an issue before, or if you can suggest a fix.