The APB Multiplexor (APB-Mux) for the DAP enables external tools and system access to the CoreSight Debug APB. The APB-Mux encapsulates the multiple interfaces into a single deliverable component, enabling multi-master access to the Debug APB.

Figure 2.30 shows the APB-Mux. External tool connection to the APB-Mux uses the APB Access Port (APB-AP) to provide an APB master interface. System access requires an APB bridge to provide the APB master interface.

Figure 2.31 shows the APB-Mux integrated into the DAP. The APB-AP Slave port is connected to the APB-AP and the System Slave port to the system bus. The system bus requires an APB bridge to connect to the APB-Mux. APB-AP and system connections must be made in the order shown in Figure 2.31 to support distinct debug and system power domains.