Serial Wire Debug (SWD) support

The Serial Wire Debug (SWD) interface or Serial Wire Debug Port (SW-DP) is one of the features of the debug  and  trace  technology  ARM  CoreSight™.  First  implementations  of  SWD  are  realized  in  the derivatives of the Cortex-M3 core Stellaris of Luminary Micro (now Texas Instruments) and in the  derivatives of  the  STM32  family  by  STMicroelectronics.  The  known  JTAG  Debug  Port  (JTAG-DP)  is  supported furthermore. Both debug ports, the SWD and the alternative JTAG debug port  can be  combined  to the Serial Wire JTAG Debug Port (SWJ-DP), the CoreSight standard port.

When using SWD, the TDO signal can provide trace event messages via the Serial Wire Output (SWO). This behaviour can be used by the Serial Wire Viewer (SWV) to output system events via a single pin:

  • Instrumentation trace ITM (printf-like Debugging)
  • Watchpoint Trace DWT, Instruction Pointer Trace
  • Event Trace (Interrupts)

The additional options are fully supported by the Universal Debug Engine as well as by PLS' Universal Access Device 2pro (UAD2pro) family, UAD2next and UAD3+.