I tried to send some keystrokes to a new Mega2560 clone. I got an IOexception from java.
java.io.IOException: Input/output error in writeArray
at gnu.io.RXTXPort.writeArray(Native Method)
at gnu.io.RXTXPort$SerialOutputStream.write(RXTXPort.java:1124)
Clip
Clip
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
There is a problem in this board, but what and where. The mega16U2 seems to work, it looks like a serial port in Device manager. And the main Cpu is working also, I can program it with the Avrisp. Its serial output is working too.
I think the problem is in Mega16U2. But it has its firmware inplace. What else?