Asynchronous, event-driven readout for large-scale imaging devices

Event-driven readout architecture offers an energy-efficient solution for reading out information from pixels when events are sparse. A frame-based readout, on the other hand, can quickly read a group of pixels without requiring multiple communication handshakes on the output bus. However, neither of the readout schemes performs well for large-scale imaging devices, with millions of pixels, when both event-based and frame-based imaging need to be supported. In this work, we propose a better readout mechanism based on token rings, which allows both event-based and frame-based readout. We introduced a shared channel to transmit additional data from the pixel, such as the integrated brightness intensity or the pixel address. We synthesized the design, verified the correct functionality using SPICE simulation, and demonstrated the use of a shared channel to communicate meaningful data from every pixel.