An external debugger can access the device through the debug access port (DAP).
The DAP implements a standard serial wire debug (SWD) Arm CoreSight™ protocol with a two-pin serial interface (SWDCLK and SWDIO).
The SWDIO pin has an internal pull-up resistor. The SWDCLK pin has an internal pull-down resistor.
There are several access ports for connecting to different parts of the system, as shown in the following table.
| AP ID | Type | Description |
|---|---|---|
| 0 | AHB-AP | CM33 access port |
| 1 | AHB-AP | AUX access port |
| 2 | CTRL-AP | Control access port |
The AHB-AP is a standard Arm component. See the ArmCoreSight SoC-400 Technical Reference Manual for more information. The control access port (CTRL-AP) is proprietary and described in more detail in CTRL-AP — Control access port.