Development of a digital readout board for the ATLAS Tile calorimeter upgrade demonstrator

During the shutdown of the ATLAS scintillating Tile calorimeter (TileCal) in 2013/14 one of its on-detector electronic modules will be replaced with a compatible hybrid demonstrator system. This is being built to fulfill all requirements for the complete upgrade of the TileCal elec- tronics in 2022 but augmented to stay compatible with the present system. We report on the hybrid systems FPGA based communication module that is responsible for receiving and unpacking com- mands using a4.8 Gbps downlink and driving a high bandwidth data uplink. The report includes key points like multi gigabit transmission, clock distribution, programming and operation of the hardware. We also report on a firmware skeleton implementing all these key points and demon- strate how timing, trigger, control and data transmission can be achieved in the demonstrator.