TWEPP 2014 - Topical Workshop on Electronics for Particle Physics

The Synchronization of CMS ECAL Trigger Primitives via Optical Links

23 Sept 2014, 17:13

1m

Centre des Congrès - Aix en Provence, France

Poster Systems First Poster Session

Speaker

Jose Carlos Rasteiro Da Silva (LIP Laboratorio de Instrumentacao e Fisica Experimental de Part)

Description

The calorimeter trigger of the CMS experiment at the LHC uses Synchronization and Link Boards (SLB) to perform the synchronization of trigger primitives (TP) from the electromagnetic and hadronic calorimeters and transmit these TPs to the Regional Calorimeter Trigger (RCT). During the first long shutdown, the SLBs will be replaced by optical SLBs (oSLBs) and the receiver mezzanines (RM) in the RCT will be replaced by optical RMs (oRMs). With this upgrade, we can send a copy of the ECAL TPs to the future calorimeter trigger, while being transparent to the current system.

Summary

The data will transmitted using optical fibres operating at 4.8 Gbps with 8b/10b encoding. The development of the oSLBs and oRMs is described. New hardware with the latest Xilinx Kintex-7 FPGAs had to be designed and new firmware was developed. No control lines or alignment flags are present in the receiver side (oRMs), therefore special techniques were implemented in order to keep the optical links aligned (e.g. by disabling TX/RX transceiver buffers). A method to remotely reprogram the FPGAs is described. The oRMs are remotely reprogrammed through the optical data stream and the oSLBs are remotely reprogrammed using VME Bus access.

A method to remotely reprogram the FPGAs is described. The remote reprogramming updates the oRMs through the optical data stream, and the oSLBs are also remotely reprogrammed using the VME Bus access.