ARM r1p3, R4, R4F Table4-32 shows how the bit values correspond with the MPU Region Size and Enable Registers., To access an MPU Region Size and Enable Register, read or write CP15 with:

System Control Coprocessor

ID013010 Non-Confidential, Unrestricted Access

Figure 4-35 MPU Region Size and Enable Registers format

Table4-32 shows how the bit values correspond with the MPU Region Size and Enable Registers.To access an MPU Region Size and Enable Register, read or write CP15 with:

MRC p15, 0, <Rd>, c6, c1, 2 ; Read Data MPU Region Size and Enable Register

MCR p15, 0, <Rd>, c6, c1, 2 ; Write Data MPU Region Size and Enable Register

Writing a region size that is outside the range results in Unpredictable behavior.c6, MPU Region Access Control Registers The MPU Region Access Control Registers hold the region attributes and access permissions for the region specified by the Memory Region Number Register.

Reserved Sub-region disable

31 65 0

Region size

1781516

Reserved

Enable

Table4-32 Region Size Register bit functions

Bits Field Function

[31:16] Reserved SBZ.

[15:8] Sub-region disable Each bit position represents a sub-region, 0-7a.

Bit [8] corresponds to sub-region 0

...

Bit [15] corresponds to sub-region 7

The meaning of each bit is:

0 =address range is part of this region

1 = address range is not part of this region.

Reserved SBZ.

[5:1] Region size Defines the region size:

b00000 - b00011=Unpredictable

b00100 = 32 bytes

b00101 = 64 bytes

b00110 = 128 bytes

b00111 = 256 bytes

b01000 = 512 bytes

b01001 = 1KB

b01010 = 2KB

b01011 = 4KB

b01100 = 8KB

b01101 = 16KB

b01110 = 32KB

b01111 = 64KB

b10000 = 128KB

b10001 = 256KB

b10010 = 512KB

b10011 = 1MB

b10100 = 2MB

b10101 = 4MB

b10110 = 8MB

b10111 = 16MB

b11000 = 32MB

b11001 = 64MB

b11010 = 128MB

b11011 = 256MB

b11100 = 512MB

b11101 = 1GB

b11110 = 2GB

b11111 = 4GB.

[0] Enable Enables or disables a memory region:

0 = Memory region disabled. Memory regions are disabled on reset.

1 = Memory region enabled. A memory region must be enabled before it is used.

a. Sub-region 0 covers the least significant addresses in the region, while sub-region 7 covers the most significant

addresses in the region. For more information, see Subregions on page7-3.