RISC mezzanines for controlling data acquisition in the NA48 experiment atCERN

A part of the LKr calorimeter data acquisition system of the NA48 experimen t (a precision measurements of epsilon/epsilon' in CP violating; K-0 --> 2 pi decays) is described. The experiment runs on the SPS north area in CERN. This paper presents some aspects of controlling the NA48 readout process b ased on commercial RIO 8260 RISC processors, which were used as a core for maintaining control algorithms. Several RISC processors were equipped with custom-made VME mezzanine boards providing interfacing, pre-processing and data formatting. These mezzanines are subjects of this paper. They are: RIO -TIC/DAT - time stamp distributor and buffered DT-bus interface, FOL-RIO - optical data formatter and event merger and "TAXI receiver" - handling trig ger data of the NA48 Level 2 trigger supervisor. Also the interface between DT-bus and S-link/PCI ij described. (C) 2000 Elsevier Science B.V. All rig hts reserved.