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

ID 683609
Date 10/04/2021
Public

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6.1.8.6. Nios® II Support

If the address span extender window is fixed, for example, the Disable Slave Control Port option is turned on, then the address span extender performs as a bridge. Components on the slave side of the address span extender that are within the window are visible to the Nios® II processor. Components partially within a window appear to the Nios® II processor as if they have a reduced span. For example, a memory partially within a window appears as having a smaller size.

You can also use the address span extender to provide a window for the Nios® II processor, so that the HPS memory map is visible to the Nios® II processor. This technique allows the Nios® II processor to communicate with HPS peripherals.

In the example, a Nios® II processor has an address span extender from address 0x40000 to 0x80000. There is a window within the address span extender starting at 0x100000. Within the address span extender's address space there is a slave at base address 0x1100000. The slave appears to the Nios® II processor as being at address:

0x110000 - 0x100000 + 0x40000 = 0x050000
Figure 221.  Nios® II Support and the Address Span Extender


The address span extender window is dynamic. For example, when the Disable Slave Control Port option is turned off, the Nios® II processor is unable to see components on the slave side of the address span extender.