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MPC555
/
MPC556
L-BUS TO U-BUS INTERFACE (L2U)
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
11-15
11.8.5 Region Attribute Registers (L2U_RAx)
Each region attribute register defines the protection attributes associated with a spe-
cific region protected by the data memory protection unit. There are four registers (x =
0...3), one for each supported region.
11.8.6 Global Region Attribute Register
The global region attribute register defines the protection attributes associated with the
memory region which is not protected under the four DMPU regions. This register also
provides enable/disable control for the four DMPU regions.
L2U_RAx
— L2U Region X Attribute Register
SPR 824 – 827
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
RESERVED
RS
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
LSB
31
RS
PP
RESERVED
G
RESERVED
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 11-9 L2U_RAx Bit Descriptions
Bit(s)
Name
Description
0:7
—
Reserved
8:19
RS
Region size
0000_0000_0000 = 4 Kbytes
0000_0000_0001 = 8 Kbytes
0000_0000_0011 = 16 Kbytes
0000_0000_0111 = 32 Kbytes
0000_0000_1111 = 64 Kbytes
0000_0001_1111 = 128 Kbytes
0000_0011_1111 = 256 Kbytes
0000_0111_1111 = 512 Kbytes
0000_1111_1111 = 1 Mbyte
0001_1111_1111 = 2 Mbytes
0011_1111_1111 = 4 Mbytes
0111_1111_1111 = 8 Mbytes
1111_1111_1111 = 16 Mbytes
20:21
PP
Protection bits
00 = No supervisor access, no user access
01 = Supervisor read/write access, no user access
10 = Supervisor read/write access, user read-only access
11 = Supervisor read/write access, user read/write access
22:24
—
Reserved
25
G
Guarded attribute
0 = Not guarded from speculative accesses
1 = Guarded from speculative accesses
26:31
—
Reserved
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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