B1.73
Debug Feature Register 0
The ID_DFR0 characteristics are:
Purpose
Provides top level information about the debug system in AArch32.
Usage constraints
This register is accessible as follows:
EL0
(NS)
EL0
(S)
EL1
(NS)
EL1
(S)
EL2 EL3
(SCR.NS = 1)
EL3
(SCR.NS = 0)
-
-
RO
RO
RO
RO
RO
Must be interpreted with the Main ID Register, MIDR.
Configurations
ID_DFR0 is architecturally mapped to AArch64 register ID_DFR0_EL1. See
.
There is one copy of this register that is used in both Secure and Non-secure states.
Attributes
ID_DFR0 is a 32-bit register.
31
12 11
8 7
0
RES
0
4 3
24 23
20 19
16 15
28 27
PerfMon
MProfDbg
MMapTrc
CopTrc
CopSDbg
CopDbg
Reserved
Figure B1-28 ID_DFR0 bit assignments
[31:28]
Reserved,
RES0
.
PerfMon, [27:24]
Indicates support for performance monitor model:
0x3
Support for
Performance Monitor Unit version 3
(PMUv3) system registers.
MProfDbg, [23:20]
Indicates support for memory-mapped debug model for M profile processors:
0x0
Processor does not support M profile Debug architecture.
MMapTrc, [19:16]
Indicates support for memory-mapped trace model:
0x0
ETM is not implemented.
0x1
Support for Arm trace architecture, with memory-mapped access.
In the Trace registers, the ETMIDR gives more information about the implementation.
CopTrc, [15:12]
Indicates support for coprocessor-based trace model:
0x0
Processor does not support Arm trace architecture, with CP14 access.
B1 AArch32 system registers
B1.73 Debug Feature Register 0
100236_0100_00_en
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B1-267
Non-Confidential
Summary of Contents for Cortex-A35
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