The AXI Specification requires that the interconnect respond to all transactions, even if the address space is not decoded to a slave. In order to comply with this requirement, we will instantiate an AXI Default Slave peripheral which will respond with a DECERR response should the HPS to FPGA AXI Master attempt to access an address which is not decoded to an instantiated component.
1. In the search field of the "Library" tab, type "default" as shown below.
2. Select the "AXI Default Slave" component and click "Add...".