PYNQ Composable Overlays Introduction

A composable overlay provides run time configuration as well as runtime hardware composability. It is based on three pillars:

  • An AXI4-Stream Switch that provides the runtime hardware composability, defining how data flow from one IP core to another.

  • DFX regions that brings new functionality to the design at runtime.

  • A Python API, built on top of pynq, that exposes the functionality to control the composable overlay in a pythonic way.


The AXI4-Stream Switch is cornerstone in achieving composability, its runtime configuration allows us to modify our design without redesigning the overlay, hence being more productive. This is the key of the composable overlay.

DFX regions are optional in a composable overlay, however, having them brings an extra dimension of flexibility making the applicability of a composable overlay broader. For instance, not all application need the same functions or some functions are rarely used.

The Composable Overlays Overview