DAP — Debug access port

An external debugger can access the device using the DAP.

The DAP is a standard Arm CoreSight™ serial wire debug port (SW-DP) that implements the serial wire debug (SWD) protocol with a two-pin serial interface (SWDCLK and SWDIO).

There are several access ports that connect to different parts of the system. See the following table for more information.

Table 1. Access port overview

AP ID	Type	Description
0	AHB-AP	Application subsystem access port
1	AHB-AP	Network subsystem access port
2	CTRL-AP	Application subsystem control access port
3	CTRL-AP	Network subsystem control access port

The AHB-AP and APB-AP access ports are standard Arm components documented in the Arm CoreSight SoC-400 Technical Reference Manual, Revision r3p2. The CTRL-AP access port is proprietary (see CTRL-AP - Control access port).