In this paper we describe the status of the development of the Data Processing Unit (DPU) of the Near-Infrared Spectro- Photometer (NISP) of the Euclid mission. The architecture of this unit is described, along with the Detector Control Unit (DCU), which operates the 16 HAWAII-2RG (H2RG), composing the NISP Focal Plane Array (FPA), by an equivalent number of SIDECAR systems. The design is evolved from the previous phases, with the implementation of a different approach in the data processing and consequently with the implementation of a large data buffer. The approach in implementing failure tolerance on this unit is described in detail; effort has been made to realize an architecture in which the impact of a single failure can be limited, in the worst case, to the loss of only one detector (out of 16). The main requirements driving the design are also described, in order to emphasize the most challenging areas and the foreseen solutions. The foreseen implementation of the on-board processing pipeline is also described, along with the basic interactions with the Instrument Control Unit (ICU) and with the Mass Memory Unit (MMU). Finally, we outline the on going activity for DPU/DCU bread-boarding.