ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Debug Registers Reference
Preamble byte 0, bits [7:0]
DBGCID1
This byte has the value 0x0D.
DBGCID1 is debug register 1021 at offset 0xFF4. Its format is:
Bits [31:8] Reserved, RAZ.
Component class, bits [7:4]
Preamble, bits [3:0]
DBGCID2
This field has the value 0x9, indicating an ARM Debug component.
This field has the value 0x0.
DBGCID2 is debug register 1022 at offset 0xFF8. Its format is:
Bits [31:8] Reserved, RAZ.
Preamble byte 2, bits [7:0]
DBGCID3
This field has the value 0x05.
DBGCID3 is debug register 1023 at offset 0xFFC. Its format is:
Bits [31:8] Reserved, RAZ.
Preamble byte 3, bits [7:0]
This field has the value 0xB1.
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