System Control
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
4-18
ID073015
Non-Confidential
4.3
Register descriptions
This section describes the implementation-defined CP15 system control registers by
coprocessor register number order that are not already described in the
ARM Architecture
Reference Manual
.
4.3.1
Main ID Register
The MIDR characteristics are:
Purpose
Provides identification information for the processor, including an
implementer code for the device and a device ID number.
Usage constraints
The MIDR is:
•
a read-only register
•
common to the Secure and Non-secure states
•
only accessible in privileged modes.
Configurations
Available in all configurations.
Attributes
See the register summary in
.
shows the MIDR bit assignments.
Figure 4-1 MIDR bit assignments
shows the MIDR bit assignments.
To access the MIDR, read the CP15 register with:
MRC p15, 0, <Rt>, c0, c0, 0; Read Main ID Register
Variant
Implementer
31
23
20 19
16 15
4 3
0
Architecture
Primary part number
Revision
24
Table 4-28 MIDR bit assignments
Bits
Name
Function
[31:24]
Implementer
Indicates the implementer code:
0x41
ARM Limited.
[23:20]
Variant
Indicates the variant number of the processor. This is the major revision number
n
in the
rn
part of
the rnpn description of the product revision status, for example:
0x4
Major revision number.
[19:16]
Architecture
Indicates the architecture code:
0xF
Defined by CPUID scheme.
[15:4]
Primary part number
Indicates the primary part number:
0xC09
Cortex-A9.
[3:0]
Revision
Indicates the minor revision number of the processor. This is the minor revision number
n
in the
pn
part of the
rnpn
description of the product revision status, for example:
0x1
Minor revision number.