Read-Out Buffers are critical components in the dataflow chain of the ATLAS Trigger/DAQ system.
At up to 75 kHz, after each Level-1 trigger accept signal, these devices receive and store
digitized data from groups of front-end electronic channels. Several Read-Out Buffers are
grouped to form a Read-Out Buffer Complex that acts as a data server for the High Level Triggers
selection algorithms and for the final data collection system. This paper describes a functional
prototype of a Read-Out Buffer based on a custom made PCI mezzanine card that is designed to
accept input data at up to 160 MB/s, to store up to 8 MB of data and to distribute data chunks at
the desired request rate. We describe the hardware of the card that is based on an Intel I960
processor and CPLDs. We present the integration of several of these cards in a Read-Out Buffer
Complex. We measure various performance figures and we discuss to which extent these can fulfill
ATLAS needs.
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