The ALICE TPC readout control unit

The front end electronics for the ALICE time projection chamber (TPC) consists of about 560000 channels packed in 128-channel units (front end card). Every front end card (FEC) incorporates the circuits to amplify, shape, digitize, process and buffer the TPC pad signals. From the control and readout point of view the FECs are organized in 216 partitions, each being an independent system steered by one readout control unit (RCU). The RCU, which is physically part of the on-detector electronics, implements the interface to the data acquisition (DAQ), the trigger and timing circuit (TTC) and the detector control system (DCS). It broadcasts the trigger and clock information to the FECs, performs the initialization and readout via a high bandwidth bus, and implements monitoring and safety control functions via a dedicated I2C-like link. This paper addresses the architecture and the system performance of the RCU