Is there any documentation on how to use Platform Designer's Address Span Extender?

Please refer to the following documents.

How to use Address Span Extender

Reference：Altera® Documents

Quartus Prime Standard Edition User Guide - Platform Designer

Quartus Prime Pro Edition User Guide - Platform Designer

There is also a video on Youtube with instructions on how to use the software. 

https://docs.altera.com/v/u/resources/649230/address-span-extender-qsys-component

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Category: Quartus® Prime (Platform Designer) 
Tools: Quartus® Prime 
Devices: -