mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 218

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

SECTION 11
MEMORY MANAGEMENT UNIT
The MPC823 implements a virtual memory management scheme that provides cache
control, storage access protection, and effective-to-real address translation. This
implementation includes separate instruction and data memory management units. The
MPC823 memory management unit is compliant with the PowerPC Microprocessor Family:
The Programming Environment for 32-Bit Microprocessors manual in relation to the
supported attributes, except that two new modes of operation have been added:
Available protection granularity sizes are page (4K, 16K, 512K, or 8M) or 1K subpage
(1K subpage resolution is supported for 4K pages only). The prefix Mx_ that appears before
a memory management unit control register name corresponds to instruction and data
cache conditions.
11.1 FEATURES
The following is a list of the memory management unit’s main features:
• PowerPC
• Domain manager mode
• 8-Entry Fully Associative Data and Instruction Translation Lookaside Buffers (TLBs)
• Multiple Page Size Support
• High Performance
• Supports Maximum of 16 Virtual Address Spaces
• Supports 16 Access Protection Groups
• Each Entry can be Programmed to Match Problem Accesses, Privileged Accesses, or
• PowerPC MSR
• Supports PowerPC tlbie and tlbia Instructions. No tlbsync Instruction is Supported,
• PowerPC mtspr/mfspr Instructions to and from the Implementation-Specific
• A Scratch Register is Available for Software Tablewalks
• Designed for Minimum Power Consumption
Both
Protection
but it is Implemented as a NOP Instruction.
Special-Purpose Registers can be Used for Programming
™
mode with extended encoding
IR
and MSR
Freescale Semiconductor, Inc.
For More Information On This Product,
MPC823 REFERENCE MANUAL
DR
Controls Memory Management Unit Translation and
Go to: www.freescale.com
11-1