ARM1156T2-S™ Technical Reference Manual 3.2.21. c9, Data TCM Region Register

The purpose of the Data TCM Region Register is to hold the base address and size of the Data TCM. It also determines if Data TCM is enabled.

The Data TCM Region Register is:

Figure 3.42 shows the arrangement of bits in the register.

Figure 3.41. Data TCM Region Register

Table 3.46 shows how the bit values correspond with the Data TCM Region Register.

Table 3.46. Data TCM Region Register bit functions

Bits	Field	Value	Function
[31:12]	Base address	Physical base address	Base address. Defines the physical base address of the Data TCM. The base address must be aligned to the size of the Data TCM. Any bits in the range [(log₂(RAMSize)-1):12] are ignored. The base address is 0 at Reset.
[11:7]	-	UNP on reads, SBZ on writes	-
[6:2]	Size	b00000 = 0KB b00011 = 4KB b00100 = 8KB b00101 = 16KB b00110 = 32KB b00111 = 64KB b01000 = 128KB b0100 = 256KB.	Size. Defines the size of the Data TCM on reads. On writes this field is ignored. See Tightly-coupled memory.
[1]	-	SBZ	Should Be Zero
[0]	En	0 = disabled 1 = enabled	Enable. Enables or disables the Data TCM.

To use the Data TCM Region Register read or write CP15 with:

For example:

MRC p15, 0, <Rd>, c9, c1, 0; Read Data TCM Region Register

MCR p15, 0, <Rd>, c9, c1, 0; Write Data TCM Region Register

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