A SHARC DSP CLUSTER AS HERA-B DAQ BUILDING-BLOCK

The CP violation experiment HERA-B at DESY [1] requires a highly selec tive on-line filtering of data due to high interaction rates and low s ignal to background ratio. This demands a hierarchical trigger system and a data acquisition with high bandwidth. A complete level of the tr igger hierarchy and the DAQ chain can be built from a single unit type : a single slot 6U VME unit carrying six ADSP21060 (SHARC) DSPs [2]. T he six SHARCs communicate via the common bus or via their link ports, which are all accessible from the front panel. Up to 350 units will be used in the experiment. Prototype units have been built and are opera ting successfully.