Debug

The Debug ID Register is:

in CP14 c0

a 32 bit read-only register

accessible in User and Privileged modes.

Figure 11-2shows the bit arrangement of the DIDR.

31

28 27

24 23

20 19

16 15

8

7

4

3

0

WRP

BRP

Context ID

Reserved

Variant

Revision

 

 

Debug architecture

 

 

 

 

 

 

 

 

version

 

 

 

 

Figure 11-2 Debug ID Register format

 

Table 11-7shows how the bit values correspond with the Debug ID Register functions.

 

 

 

 

Table 11-7 Debug ID Register functions

 

 

 

Bits

Field

Function

 

 

 

[31:28]

WRP

Number of Watchpoint Register Pairs:

 

 

b0000 = 1 WRP

 

 

b0001 = 2 WRPs

 

 

...

 

 

 

 

b0111 = 8 WRPs.

 

 

 

[27: 24]

BRP

Number of Breakpoint Register Pairs:

 

 

b0001 = 2 BRPs

 

 

b0010 = 3 BRPs

 

 

...

 

 

 

 

b0111 = 8 BRPs.

 

 

 

[23:20]

Context

Number of Breakpoint Register Pairs with context ID comparison capability:

 

 

b0000 = 1 BRP has context ID comparison capability

 

 

 

[19:16]

Debug architecture

Debug architecture version:

 

version

b0100 denotes ARMv7 Debug.

 

 

 

[15:8]

Reserved

RAZ.

 

 

 

[7: 4]

Variant

Implementation-defined variant number. See Product revision information on page 1-24

 

 

for details of the value of this field.

 

 

 

[3: 0]

Revision

Implementation-defined revision number. See Product revision information on

 

 

page 1-24for details of the value of this field.

 

 

 

 

 

The values of the following fields of the Debug ID Register agree with the values in CP15 c0, Main ID Register:

DIDR[3:0] is the same as CP15 c0 bits [3:0]

DIDR[7:4] is the same as CP15 c0 bits [23:20].

See c0, Main ID Register on page 4-14for more information of CP15 c0, Main ID Register.

The reason for duplicating these fields here is that the Debug ID Register is also accessible through the APB slave port. This enables an external debugger to determine the variant and revision numbers without stopping the processor.

ARM DDI 0363E

Copyright © 2009 ARM Limited. All rights reserved.

11-11

ID013010

Non-Confidential, Unrestricted Access

 

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ARM R4F, r1p3 manual Debug ID Register functions, Wrp, Brp