Intel® Quartus® Prime Standard Edition User Guide: Platform Designer

ID 683364
Date 12/15/2018
Public
Document Table of Contents

4.1.8. Address Span Extender

The Address Span Extender allows memory-mapped master interfaces to access a larger or smaller address map than the width of their address signals allows. The address span extender splits the addressable space into multiple separate windows, so that the master can access the appropriate part of the memory through the window.

The address span extender does not limit master and slave widths to a 32-bit and 64-bit configuration. You can use the address span extender with 1-64 bit address windows.

Figure 123. Address Span Extender

If a processor can address only 2 GB of an address span, and your system contains 4 GB of memory, the address span extender can provide two, 2 GB windows in the 4 GB memory address space. This issue sometimes occurs with Intel SoC devices.

For example, an HPS subsystem in an SoC device can address only 1 GB of an address span within the FPGA, using the HPS-to-FPGA bridge. The address span extender enables the SoC device to address all the address space in the FPGA using multiple 1 GB windows.