System Control Coprocessor
ARM DDI 0301H Copyright © 2004-2009 ARM Limited. All rights reserved. 3-96
ID012310 Non-Confidential, Unrestricted Access
Attempts to access the Instruction TCM Non-secure Control Access Register in modes other
than Secure Privileged result in an Undefined exception.
To use the Instruction TCM Non-secure Control Access Register read or write CP15 with:
• Opcode_1 set to 0
• CRn set to c9
• CRm set to c1
• Opcode_2 set to 3.
For example:
MRC p15,0,<Rd>,c9,c1,3 ;Read Instruction TCM Non-secure Control Access Register
MCR p15,0,<Rd>,c9,c1,3 ;Write Instruction TCM Non-secure Control Access Register
3.2.29 c9, TCM Selection Register
The purpose of the TCM Selection Register is to determine the bank of CP15 registers related
to TCM configuration in use. These banks consist of:
• c9, Data TCM Region Register on page 3-89
• c9, Instruction TCM Region Register on page 3-91
• c9, Data TCM Non-secure Control Access Register on page 3-93
• c9, Instruction TCM Non-secure Control Access Register on page 3-94.
The TCM Selection Register is:
•in CP15 c9
• a 32-bit read/write register banked in the Secure and Non-secure worlds
• accessible in privileged modes only.
Figure 3-54 shows the bit arrangement for the TCM Selection Register.
Figure 3-54 TCM Selection Register format
Table 3-93 lists how the bit values correspond with the TCM Selection Register functions.
SBZ
31 210
TCM number
Table 3-93 TCM Selection Register bit functions
Bits Field name Function
[31:2] - UNP/SBZ.
[1:0] TCM number Selects the bank of CP15 registers related to TCM configuration. Attempts to select a bank
related to a TCM that does not exist are ignored:
b00 = TCM 0, reset value.
b01 = TCM 1. When there is only one TCM on both Instruction and Data sides, write access is
ignored.
b10 = Write access ignored.
b11 = Write access ignored.
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