# Overlay¶

The Overlay class is used to load PYNQ overlays to the PL, and manage and control existing overlays. The class is instantiated with the .bit file for an overlay. By default the overlay Tcl file will be parsed, and the bitstream will be downloaded to the PL. This means that to use the overlay class, a .bit and .tcl must be provided for an overlay.

## Examples¶

from pynq import Overlay



The .bit file path can be provided as a relative, or absolute path. The Overlay class will also search the packages directory for installed packages, and download an overlay found in this location. The .bit file is used to locate the package.

base = Overlay("base.bit", download=False) # Overlay is instantiated, but bitstream is not downloaded to PL


base.ip_dict