The CMS DT muon DDU: a PMC based interface between frontend and data-acquisition

CMS will use gas Drift Tubes (DT) as active part of the barrel muon sub-detector. In total 200.000 wires will be readout by TDCs and signals will be sent to Data Acquisition System (DAS). The entrance door to the standard CMS DAS will be a board (Detector Dependent Unit DDU) that will be specific to each sub-detector. We have built a PCI Mezzanine Card (PMC) based prototype of the DT muon DDU that features two input channels with Optolink, data check and reconstruction by FPGA and PCI slave output through a FIFO. A description of the board and the FPGA schematics will be given together with the lab setup used to test and debug it.