ATLAS LAr Calorimeter Commissioning for LHC Run-3

The Liquid Argon calorimeter of the ATLAS detector provides inputs to the first level of the ATLAS trigger. After successful period of data-taking during the LHC Run-2 the ATLAS detector entered into a long period of shutdown. In 2022 the LHC has started a new data taking period Run-3. The Run-3 period (2022 - 2025) expects to have higher luminosity than Run-2 with pile-up of up to 80 interactions per bunch crossing. To cope with this harsh conditions, a new trigger readout system has been installed during the long shutdown. The new system should improve significantly the triggering performances on electromagnetic objects. This will be achieved by increasing the granularity of the readout system available at the trigger level by up to a factor of ten. This new trigger system is under commissioning in order to make the new system as the main trigger readout system in 2023. This contribution will present the current status of the Liquide Argon Clorimeters system and the commissioning to be completed towards the full operation of the new trigger readout system for the LHC Run-3.