<secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> <record> <contributors> <authors> <author>Garvey, J.</author> <author>Hillier, S.</author> <author>Mahout, G.</author> <author>Moye, T. H.</author> <author>Staley, R. J.</author> <author>Watkins, P.M.</author> <author>Watson, A.</author> <author>Achenbach, R.</author> <author>Hanke, P.</author> <author>Kluge, E-E.</author> <author>Meier, K.</author> <author>Meshkov, P.</author> <author>Nix, O.</author> <author>Penno, K.</author> <author>Schmitt, K.</author> <author>Ay, C.</author> <author>Bauss, B.</author> <author>Dahlhoff, A.</author> <author>Jakobs, K.</author> <author>Mahboubi, K.</author> <author>Schäfer, U.</author> <author>Trefzger, T.</author> <author>Eisenhandler, E.</author> <author>Landon, M.</author> <author>Moyse, E.</author> <author>Thomas, J.</author> <author>Apostoglou, P.</author> <author>Barnett, B. M.</author> <author>Brawn, I.P.</author> <author>Davis, A.O.</author> <author>Edwards, J.</author> <author>Gee, C. N. P.</author> <author>Gillman, A. R.</author> <author>Perera, V. J. O.</author> <author>Qian, W.</author> <author>Bohm, C.</author> <author>Hellman, S.</author> <author>Hidvégi, A.</author> <author>Silverstein, S.</author> </authors> </contributors> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <keywords> <keyword>trigger</keyword> <keyword>calorimeter</keyword> <keyword>FPGA</keyword> <keyword>Level-1</keyword> <keyword>ATLAS</keyword> <keyword>pipeline</keyword> </keywords> <dates> <year>2003</year> <pub-dates> <date>31 May 2003</date> </pub-dates> </dates> <abstract>The architecture of the ATLAS Level-1 Calorimeter Trigger system (L1Calo) is presented. Common approaches have been adopted for data distribution, result merging, readout, and slow control across the three different subsystems. A significant amount of common hardware is utilized, yielding substantial savings in cost, spares, and development effort. A custom, high-density backplane has been developed with data paths suitable for both the em/tt cluster processor (CP) and jet/energy-summation processor (JEP) subsystems. Common modules also provide interfaces to VME, CANbus and the LHC Timing, Trigger and Control system (TTC). A common data merger module (CMM) uses FPGAs with multiple configurations for summing electron/photon and tau/hadron cluster multiplicities, jet multiplicities, or total and missing transverse energy. The CMM performs both crate- and system-level merging. A common, FPGA-based readout driver (ROD) is used by all of the subsystems to send input, intermediate and output data to the data acquisition system (DAQ), and region-of-interest (RoI) data to the level-2 triggers. Extensive use of FPGAs throughout the system makes the trigger flexible and upgradeable, and several architectural choices have been made to reduce the number of inter-crate links and make the hardware more robust.</abstract> </record> <record> <contributors/> <titles> <title/> <secondary-title/> </titles> <doi/> <pages/> <volume/> <number/> <dates> <year/> </dates> <abstract/> </record> </records> </xml>