Commissioning of L1Calo Phase I Upgrade at ATLAS: development and testing of eFEX and FTM modules

The ATLAS level-1 calorimeter trigger (L1Calo) is a hardware system that identifies events containing calorimeter-based physics objects. In preparation for Run 3 with increased pileup ($\mu\sim65$), L1Calo is currently implementing a significant programme of planned upgrades. The existing hardware will be replaced by a new system of feature extractor (FEX) modules with improved input granularity and algorithms. Here we focus on the current ongoing testing and commissioning of the electron feature extractor (eFEX) and the FEX Test Module (FTM) at the recent slice tests at CERN. The online software developments required to do this are also discussed