8 Appendix B: DSU.DID vs JTAG ID
The JTAG ID at memory location 0x4400_0090 is left in the device for legacy reasons and/or for being read over JTAG during private test modes. The device ID to be used by an external debugger or programmers must be within the DSU [DSU.DID register] located at address 0x4100_00118 (external address) or 0x4100_0018 (internal address). Only the lower 16 bits of this register are used for the purpose of external tools to identify the device. It is recommended that the upper 16 bits be masked off on read.
Many of the fields in the JTAG ID and the DSU.DID register are the same, but positioned differently.
The DSU.DID register has some of its bit fields loaded from the TCFG registers in the Flash RSVD Page 7 (Factory Test Memory), which includes addresses from 0x0004_7000 to 0x0004_7FFF.
Refer to the following figure for how the JTAG ID and DSU.DID are correlated, and refer to Appendix A: Device JTAG IDs and DSU Device ID.
