r8a77850anbg Renesas Electronics Corporation., r8a77850anbg Datasheet - Page 176

Manufacturer Part Number

r8a77850anbg

Renesas 32-bit Risc Microcomputer Superh? Risc Engine Family

Manufacturer

Renesas Electronics Corporation.

Manufacturer

BOSTOCK HK LIMITED

Part Number:

r8a77850anbgV

Manufacturer:

Renesas Electronics America

7. Memory Management Unit (MMU)

This LSI supports a 32-bit virtual address space, and can access a 4-Gbyte address space. The

virtual address space is divided into a number of areas, as shown in figures 7.2 and 7.3. In

privileged mode, the 4-Gbyte space from the P0 area to the P4 area can be accessed. In user mode,

a 2-Gbyte space in the U0 area can be accessed. When the SQMD bit in the MMU control register

(MMUCR) is 0, a 64-Mbyte space in the store queue area can be accessed. When the RMD bit in

the on-chip memory control register (RAMCR) is 1, a 16-Mbyte space in on-chip memory area

can be accessed. Accessing areas other than the U0 area, store queue area, and on-chip memory

area in user mode will cause an address error.

When the AT bit in MMUCR is set to 1 and the MMU is enabled, the P0, P3, and U0 areas can be

mapped onto any physical address space in 1-, 4-, 64-Kbyte, or 1-Mbyte page units in TLB

compatible mode and in 1-, 4-, 8-, 64-, 256-Kbyte, 1-, 4-, or 64-Mbyte page units in TLB extended

mode. By using an 8-bit address space identifier, the P0, P3, and U0 areas can be increased to a

maximum of 256. Mapping from the virtual address space to the 29-bit physical address space is

carried out using the TLB.

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REJ09B0261-0100

Virtual Address Space

Address Spaces

Figure 7.2 Virtual Address Space (AT in MMUCR = 0)

Privileged mode

Non-cacheable

address space

On-chip memory area

Store queue area

Address error