  The KM3NeT Collaboration has already produced more than one thousand
acquisition boards, used for building two deep-sea neutrino detectors at the
bottom of the Mediterranean Sea, with the aim of instrumenting a volume of
several cubic kilometers with light sensors to detect the Cherenkov radiation
produced in neutrino interactions. The the so-called Digital Optical Modules,
house the PMTs and the acquisition and control electronics of the module, the
Central Logic Board, which includes a Xilinx FPGA and embedded soft processor.
The present work presents the architecture and functionalities of the software
embedded in the soft processor of the Central Logic Board.
