The final design of the ATLAS Trigger/DAQ Readout-Buffer Input (ROBIN) Device

The ATLAS readout subsystem (ROS) is the main interface between 1600 detector front-end readout links (ROL) and the high level (HLT) trigger farms. Its core device, the readout-buffer input (ROBIN), accepts event data on 3 readout links (ROLs) with a maximum rate of 100 kHz and a bandwidth of up to 160\,MB/s per link. Incoming event data is temporarily buffered and delivered via PCI or Gigabit Ethernet on request. Two devices, a XILINX XC2V2000 FPGA and an IBM PowerPC 440, are present, implementing the ROBIN's functionality. Furthermore one 64 MB SDRAM event data buffer is available per ROL. The device supports the ATLAS baseline implementation, which foresees the PCI bus as the main communication path inside the ROS, as well as an optional data path using Gigabit Ethernet to increase scalability when needed. The paper presents the final design of the ATLAS ROBIN. Measurement results, obtained with a prototype device in PCI bus and Gigabit Ethernet setups, show the usability and approve the design choices.