ARM r1p3, R4, R4F

System Control Coprocessor

ID013010 Non-Confidential, Unrestricted Access

To access the MPU Region Access Control Registers read or write CP15 with:

MRC p15, 0, <Rd>, c6, c1, 4 ; Read Region access control Register

MCR p15, 0, <Rd>, c6, c1, 4 ; Write Region access control Register

To execute instructions in User and Privileged modes:

• the region must have read access as defined by the AP bits

• the XN bit must be set to 0.

c6, MPU Memory Region Number Register

The MPU Region Registers are multiple registers with one register for each memory region

implemented. The value contained in the MPU Memory Region Number Register determines

which of the multiple registers is accessed.

The MPU Memory Region Number Registers are:

• read/write register

• accessible in Privileged mode only.

Figure 4-37 shows the arrangement of bits in the register.

Figure 4-37 MPU Memory Region Number Register format

Table4-35 shows how the bit values correspond with the MPU Memory Region Number

To access the MPU Memory Region Number Register, read or write CP15 with:

MRC p15, 0, <Rd>, c6, c2, 0 ; Read MPU Memory Region Number Register

MCR p15, 0, <Rd>, c6, c2, 0 ; Write MPU Memory Region Number Register

Writing this register with a value greater than or equal to the number of regions from the MPU

Type Register is Unpredictable. Associated register bank accesses are also Unpredictable.

b011 Read/write Read/write Full access

b100 UNP UNP Reserved

b101 Read-only No access Privileged read-only

b110 Read-only Read-only Privileged/User read-only

b111 UNP UNP Reserved

Table4-34 Access data permission bit encoding (continued )

AP bit values Privileged permissions User permissions Description

31 40

Reserved Region

Table4-35 MPU Memory Region Number Register bit functions

Bits Field Function

[31:4] Reserved SBZ.

[3:0] Region Defines the group of registers to be accessed. Read the MPU Type Register to determine the number

of supported regions, see c0, MPU Type Register on page4-17.