The CMS Level-1 Calorimeter Trigger Upgrade for LHC Run II

The CMS Level-1 Calorimeter Trigger was successfully upgraded, commissioned and employed in the recording of LHC collision in 2016. The upgraded trigger is conceived to maximise the selection performance in conditions of high luminosity and large multiplicity of simultaneous inelastic collision per crossing. This is achieved through a Time-Multiplexed architecture which enables the calorimeter data at full spacial granularity of a single event to be processed by a single trigger processor over multiple bunch crossings. The modular hardware design is based on the $\mu $ TCA standard. The calorimeter trigger processor boards are equipped with Xilinx Virtex7 FPGAs and 10 Gbps optical links. Sophisticated and innovative algorithms exploit the full event information to reconstruct lepton and jet candidates. The commissioning and running of the upgraded trigger will be presented with a summary of the performance in 2016.