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Memory Management Unit (MMU)
4-4
Freescale Semiconductor
4.2.1
Address Space ID (ASID)
The address space ID (ASID) is located in a CPU space-control register. The 8-bit ASID value is mapped
into CPU space at address 0x003 and is accessed using a MOVEC instruction. The
ColdFire Family
Programmer’s Reference Manual
describes MOVEC.
4.2.2
MMU Base Address Register (MMUBAR)
The default reset state is an invalid MMUBAR; The MMU is disabled and the memory-mapped space is
not visible.
MMUBAR
+ 0x0018
MMUDR—MMU read/write TLB data register
32
R/W
0x0000_0000
1
The address listed here represents the value of the Rc field used when accessing the core registers via the BDM port. For
more information see
Rc[11:0]: 0x003 (ASID)
Access: Supervisor read/write
7
6
5
4
3
2
1
0
R
ID
W
Reset:
0
0
0
0
0
0
0
0
Figure 4-2. Address Space ID (ASID)
Table 4-2. ASID Field Descriptions
Field
Description
7–0
ID
This 8-bit field is the current user ASID. The ASID is an extension to the virtual address. Address space 0x00
may be reserved for supervisor mode. See address space mode functionality in
.” The other 255 address spaces are used to tag user processes. The TLB entry ASID
values are compared to this value for user mode unless the TLB entry is marked shared (MMUTR[SG] is set).
The TLB entry ASID value may be compared to 0x00 for supervisor accesses.
Rc[11:0] 0x008 (MMUBAR)
Access: Supervisor read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R
BA
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
V
W
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 4-3. MMU Base Address Register (MMUBAR)
Table 4-1. MMU Memory Map (continued)
Address
Register
Width Access
Reset Value
Section/Page
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...