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Home > System Control > Register descriptions > c9, BTCM Region Register |
The BTCM Region Register characteristics are:
Holds the base address and size of the BTCM.
Determines if the BTCM is enabled.
The BTCM Region Register is:
a read/write register
accessible in Privileged mode only.
Available in all processor configurations.
See Table 4.43.
Figure 4.41 shows the BTCM Region Register bit assignments.
Table 4.43 shows the BTCM Region Register bit assignments.
Table 4.43. BTCM Region Register bit assignments
Bits | Name | Function | ||
---|---|---|---|---|
[31:12] | Base address | Base address. Defines the base address of the BTCM. The base address must be aligned to the size of the BTCM. Any bits in the range [(log2(RAMSize)-1):12] are ignored. At reset, if LOCZRAMAm is set to: 0 =The initial base address is 1 =The initial base address is implementation-defined. See Configurable options. | ||
[11:7] | - | UNP on reads, SBZ on writes. | ||
[6:2] | Size | Size. Indicates the size of the BTCM on reads. On writes this field is ignored. See About the TCMs. | ||
b00000 = 0KB, no TCM b00011 = 4KB b00100 = 8KB b00101 = 16KB | b00110 = 32KB b00111 = 64KB b01000 = 128KB b01001 = 256KB | b01010 = 512kB b01011 = 1MB b01100 = 2MB b01101 = 4MB b01110 = 8MB | ||
[1] | - | SBZ. | ||
[0] | Enable | Enables or disables the BTCM. 0 = Disabled 1 = Enabled. The reset value of this field is determined by the INITRAMBm input pin. This bit is RAZ if the processor has been implemented or integrated without a BTCM. |
To access the BTCM Region Register, read or write CP15 with:
MRC p15, 0, <Rd>, c9, c1, 0 ; Read BTCM Region Register
MCR p15, 0, <Rd>, c9, c1, 0 ; Write BTCM Region Register