To make High Dynamic Range image sensors easier to integrate in cameras and subsystems, Pyxalis proposes a novel digital architecture, making the management of image acquisition and the reconstruction of HDR images much simpler. This work describes the development and characterization of a 120dB High Dynamic Range sensor based on a novel processor based architecture. Two processors are embedded in the detector to allow flexible shutter operation, windowing, sequencing as well as High Dynamic Range modes. Thanks to built in HDR reconstruction , the image sensor outputs 20bits per pixels based on 14bits column ADCs and two complementary HDR image acquisition methods. The entire image acquisition is fully synchronous.