How the debug hardware unit autodetects Serial Wire Debug

Serial Wire Debug (SWD) does not support a scan chain in the same way that JTAG does. When autoconfiguring in SWD mode, the debug hardware unit:

  1. Adds the ARMCS-DP device to the scan chain configuration.

  2. Optionally reads the CoreSight ROM Table to add the remaining devices. This is done by default, but you can override this.


Be aware that if your target supports both JTAG and SWD, then you must enable Use SWJ Switching in the Advanced configuration settings before autoconiguring the scan chain.

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