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What is the ID Code of a Cortex-M0 DAP or Cortex-M0+ DAP?

Applies to: CoreSight

Answer

A CoreSight-compatible Debug Access Port (DAP) contains a Debug Port Identification Register (DPIDR) to allow a debugger to recognize which Debug Port (DP) component is present. The fields within the DPIDR are described the ARM Debug Interface v5 Architecture Specification (ADIv5).

The Cortex-M0 r0p0 customized DAP (CM0DAP) conforms to DP architecture version 1 described in the ADIv5.1 Supplement and later versions.

The CM0DAP (r0p0) has an ID code of 0x0BB11477, irrespective of which debug protocol being used - JTAG, or Serial Wire Debug (SWD). This values shows a part number (PARTNO) of 0xBB, which is distinct from the standard CoreSight JTAG-DP and SW-DP part number of 0xBA, and it indicates that this DP is designed by ARM, conforms to architecture version 1 and uses the Minimal Debug Port (MinDP) implementation.

  JTAG_DPIDR_REG_VAL  = 32'h0BB11477;
  SW_DPIDR_REG_VAL = 32'h0BB11477;

The Cortex-M0+ r0p0 customized DAP (CM0PDAP) conforms to DP architecture version 1 described in the ADIv5.1 Supplement and later versions, but if the Multi-Drop Serial Wire option is implemented (an RTL configuration option), the DP conforms to DP architecture version 2. The PARTNO of this MinDP is 0xBC and the VERSION field reflects the DP architecture version, giving DPIDR identities as follows:

  JTAG_DPIDR_REG_VAL  = 32'h0BC11477;
  SW_DPIDR_REG_VAL1 = 32'h0BC11477; // DP Architecture 1
  SW_DPIDR_REG_VAL2 = 32'h0BC12477; // DP Architecture 2

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