I wanted to read some data from an external microcontroller via the UART, but couldn't get any communication working.
After checking the RXD and TXD pins, I saw that there is also a signal on the RXD-pin of the Raspberrypi (actually its the same signal as on TXD / same level).
Screenshot of Oscilloscope connected to pin 8 (yellow) and pin 10 (blue) of the GPIO: http://i.imagebanana.com/img/oy96inb9/SCR04.PNG
Any Ideas why there is a signal on the RXD pin of the RPi? Or is my RPi just broken?