µPD705100
2. ADDRESS SPACE
2.1 Memory Space
The V830 uses four chip select/address pins and 26 address bus pins to represent a 32-bit address. When the
chip select function is used, a 256M-byte image space is created as three spaces and a 32M-byte image space is
created as one space. When the chip select function is not used, a 4G-byte linear address space is created.
Area 40000000H-7FFFFFFFH in the memory space is reserved as an uncachable area. When this area is
accessed, the cache function is not effective. For all other areas, the cache function is effective.
Within the memory space, built-in instruction RAM and built-in data RAM are mapped. By accessing these areas,
an instruction can be fetched and data loaded/stored within one cycle (internal clock) without activating a bus cycle
externally. Data in the built-in instruction RAM, however, cannot be accessed by using the load/store instructions. Nor
can instructions be fetched from the built-in data RAM. These built-in RAMs are mapped to the cachable area; however,
they are not cached.
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