The command and data processing unit of the euclid visible imager: Impact of the data compression needs on the unit design

The Command and Data Processing Unit (CDPU) of the Euclid Visible Imager is one of the two warm electronics units of the instrument. It implements on one side the digital interface to the satellite, for telecommandsacquisition and telemetrydownloading, and on the other side the interface to the focal plane CCDs readout electronics, for science data acquisition and compression. The CDPU main functionalities include the instrument commanding, control and health monitoring. The baseline unit architecture is presented, reporting the results of the phase B1 study and of the trade-off activity carried out to check the performances of the SW implementation of two different lossless compressionalgorithms on the baseline target processor (LEON3-FT) and on a HW compressor. © 2012 SPIE.