HD6417705F133V Datasheet, PDF (115/741 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

3.1.1 MMU of This LSI
Virtual Address Space: This LSI supports a 32-bit virtual address space that enables access to a
4-Gbyte address space. As shown in figures 3.2 and 3.3, the virtual address space is divided into
several areas. In privileged mode, a 4-Gbyte space comprising areas P0 to P4 is accessible. In user
mode, a 2-Gbyte space of U0 area is accessible. Access to any area excluding the U0 area in user
mode will result in an address error.
If the MMU is enabled by setting the AT bit of the MMUCR register to 1, P0, P3, and U0 areas
can be used as any physical address area in 1- or 4-kbyte page units. By using an 8-bit address
space identifier, P0, P2, and U0 areas can be increased to up to 256 areas. Mapping from virtual
address to 29-bit physical address can be achieved by the TLB.
1. P0, P3, and U0 Areas
The P0, P3, and U0 areas can be address translated by the TLB and can be accessed through
the cache. If the MMU is enabled, these areas can be mapped to any physical address space in
1- or 4-kbyte page units via the TLB. If the CE bit in the cache control register (CCR1) is set
to 1 and if the corresponding cache enable bit (C bit) of the TLB entry is set to 1, access via the
cache is enabled. If the MMU is disabled, replacing the upper three bits of an address in these
areas with 0s creates the address in the corresponding physical address space. If the CE bit of
the CCR1 register is set to 1, access via the cache is enabled. When the cache is used, either
the copy-back or write-through mode is selected for write access via the WT bit in CCR1.
If these areas are mapped to the on-chip module control register area in area 1 in the physical
address space via the TLB, the C bit of the corresponding page must be cleared to 0.
2. P1 Area
The P1 area can be accessed via the cache and cannot be address-translated by the TLB.
Whether the MMU is enabled or not, replacing the upper three bits of an address in these areas
with 0s creates the address in the corresponding physical address space. Use of the cache is
determined by the CE bit in the cache control register (CCR1). When the cache is used, either
the copy-back or write-through mode is selected for write access by the CB bit in the CCR1
register.
3. P2 Area
The P2 area cannot be accessed via the cache and cannot be address-translated by the TLB.
Whether the MMU is enabled or not, replacing the upper three bits of an address in this area
with 0s creates the address in the corresponding physical address space.
4. P4 Area
The P4 area is mapped to the on-chip module control register of this LSI. This area cannot be
accessed via the cache and cannot be address-translated by the TLB. Figure 3.4 shows the
configuration of the P4 area.
Rev. 2.00, 09/03, page 67 of 690