Dev Bugfx Empty buffer indication and stability improvments: The mux prototype used ASCII coding for channel selection while the current realization used real number (0...4) for addressing the mux. The UART read function uses the '0' to indicate an empty buffer element. The mux now loops back '0' used by channel selection causing the read function to process the data. As result data interrups are visible at the display. To avoid this another character has been defined indicate empty buffer locations. Beside this the functionality has been improved with regard to access speed and better recovery in case of transition failure.