Objective Development Forums

Hey,
we are currently hacking arround with vusb and atmega 168 µC. We have successfully build a breadboard version of the metaboard (minimal setup) and then flashed the atmega with vusb example firmware (hid-data).
now we have some trouble here regarding a stable usb connection. we found out that if we connect a Blue (or other color) LED between High and Low on our board (we run everything with 3,3V from LF33CV) we have a stable connection and we can read with hidtool and also write. But: immediately when we pull out the led the connection is lost! When we put the LED back in, the connection is imediatly back on.
So can someone give us an answear to the question why we have to put in an LED??? We can repoduce this on two different boards with two different atmega 168...

Can you share your schematic with us? Is it exactly like the schematic for the Metaboard, or are there some changes? Can you try it on a different computer?

I don't know much about electronics, but my first guess in this situation would be to think that it might be an EMI issue? Do you have decoupling capacitors on all of your power pins to the AVR? Hope it helps...