Quartus® Prime Pro Edition User Guide: Platform Designer

ID 683609
Date 9/30/2024
Public
Document Table of Contents

4.5.4.3. Address Space Translation

The agent interface of a pipeline or clock crossing bridge has a base address and address span. You can set the base address, or allow Platform Designer to set it automatically. The address of the agent interface is the base offset address of all the components connected to the bridge. The address of components connected to the bridge is the sum of the base offset and the address of that component.

The host interface of the bridge drives only the address bits that represent the offset from the base address of the bridge agent interface. Any time a host accesses an agent through a bridge, both addresses must be added together, otherwise the transfer fails. The Address Map tab displays the addresses of the agents connected to each host and includes address translations caused by system bridges.

Figure 172. Bridge Address Translation

In this example, the Nios® II processor connects to a bridge located at base address 0x1000, an agent connects to the bridge host interface at an offset of 0x20, and the processor performs a write transfer to the fourth 32-bit or 64-bit word within the agent. Nios® II drives the address 0x102C to interconnect, which is within the address range of the bridge. The bridge host interface drives 0x2C, which is within the address range of the agent, and the transfer completes.