Where do transactions to undefined addresses get routed to in QSys?

Description

Avalon®-MM or AXI™ transactions that are not to a specified address in your Qsys system will be routed to the default slave.  In version 13.0 and later of the Quartus® II software, you can choose the default slave.

When the default slave is not specified, the default slave will be one chosen out of the existing slaves that are connected to a master.  The slave that is chose is undeteministic.

Resolution

To choose a slave component that will be the default slave in Qsys, follow the instructions below:

1) Right click on the title bar within the System Contents tab
2) Tick Show Default Slave column.
3) Any slave interface may be chosen as the default slave.