  The LHC upgrade is planned to enhance the instantaneous luminosity during Run
3 from 2021 through 2023. The Phase-I upgrade of the trigger readout
electronics for the ATLAS Liquid Argon (LAr) Calorimeters will be installed
during the second long shutdown of LHC in 2019-2020. In this upgrade, the
so-called super cells are introduced to provide higher granularity, higher
resolution and longitudinal shower shape information from the LAr calorimeters
to the level-1 trigger processors. A new LAr Trigger Digitizer Board (LTDB)
will manipulate and digitize 320 channels of super cell signals, and transmit
it via 40 fiber optical links to the back end where data are further processed
and transmitted to the trigger processors. Five pairs of bidirectional GBT
links are used for slow control from the Front-end LInks eXchange (FELIX) in
the ATLAS TDAQ system. LTDB also outputs 64 summed analog signals to the
current Tower Builder Board via the new baseplane. A test system is developed
to test all functions of the LTDB and carry out the performance measurement. A
back end PCIe card is designed which has the circuit to interface to the ATLAS
trigger, time and control system. It can control the generation of injection
signals to the LTDB for performance test. It also configures and calibrate all
ASICs on the LTDB.
