Readout Control Specifications for the Front-End and Back-End of the LHCb Upgrade

The LHCb experiment has proposed an upgrade towards a full 40 MHz readout system [1] in order to run at between five and ten times the initial design luminosity. The various sub-systems in the readout architecture will need to be upgraded in order to cope with higher sub-detector occupancies, higher rate and higher network load. The development of a new readout control system for the upgraded LHCb readout system was investigated already in 2008 [2]. This work has evolved into a detailed system-level specification of the entire timing and readout control system [3]. In this paper, we specify in detail the functionalities that must be supported by the Front-End and the Back-End electronics to comply with the timing requirements and the readout scheme, and the necessary control and monitoring capabilities in order to validate, commission and operate the upgraded experiment efficiently and with sufficient flexibility. The document focuses entirely on the readout control aspects of the FE and BE, and the ECS interface to the on-detector systems. It identifies the other aspects of the upgraded readout architecture which require further specification and consensus before the specification of the timing, readout control, and the ECS interface to the FE can be fully completed. The document leaves out the description of the control of the readout to the farm, the event management, the global performance monitoring, and the implementation of the operational procedures which will become evident and finalized during the commissioning phase.