Blue Flower

DDL Products

CRORC v.1.2

Common Read-out Receiver Card


The CRORC is a PCI Express Read-out Receiver Card for reading out high-speed optical links of CERN experiments (ALICE, ATLAS). It recieves data from up to 12 optical links through duplex optical cables, and writes it (with DMA) to the computer memory via the PCI Express bus. Its Virtex-6 FPGA is capable of doing high-level data processing and reduction by hardware.


  • Up to 6.25 Gb/s optical data links (12x)
  • 600 MB/s maximum bandwidth per channel
  • 4 000 MB/s, max. aggregate data throughput
  • Complies with CERN proprietary Detector Data Links (DDL1, DDL2) w/ appropriate firmware
  • Custom designed daughter boards with FMC interface

DDL Features

  • Instant-on, (automatic link synchronization and management)
  • Supports remote control and firmware upgrades of the Front-end system
  • Bit error rate << 10-12, very high error detection rate, CRC check on data blocks
  • Standby support


  • Three user replaceable QSFP optical transceivers with MPO/MTP optical connectors
  • Interoperable with single links through MTP-duplex LC break-out cables
  • x8, Gen2 PCI Express interfacee
  • Compatible with: SIU, RORCv3, RORCv2


The CRORC was developed by the University of Frankfurt and CERN with hardware design contribution of Cerntech Ltd. Different types of firmware for different data acquisition and data processing functionalities have been developed in Frankfurt, and at different experiments (ALICE, ATLAS) at CERN.

For further refernces see: