I've just bought an Arduino Duemilanove yesterday and i'm trying to interface it with my netbook.
I loaded the "LED_Blink" program on the board and worked: the LED on the pin 13 blinked at the right delay.
Then i loaded Firmata v2 on the Arduino, so i could use Processing to communicate with it.
Strangely, when using the Processing version of "LED_Blink" (copy-pasted directly from here "arduino.cc/playground/Interfacing/Processing" ) the LED on pin 13 doesn't blink at all, instead the Rx LED turns on with the correct delay (sometimes, even teaming up with the Tx LED and blinking together ); i tried to change pin, using pin 2 and an external LED, but nothing happens. I also tried to measure the output voltage from the pins setted as output and the multimeter reads 0,37 V!
If it wasn't odd enough, if i load the Arduino sketch directly on the board it works flawlessly.
Am i missing something? Are there any connection to short or some pullup/pulldown resistors to enable/add?
I'm not using any custom code at the moment, only the standard sketch for LED Blinking.