SM8521 Datasheet, PDF (45/56 Pages) Sharp Electrionic Components – 8-Bit Single-Chip Microcomputer

SM8521
MMU
The SM8521 supports an MMU used to external
memory area expansion.
Memory area 1000H-9FFFH, can be expanded to
2M-byte in each 8k-byte unit.
15
13 12
0
CPU address
7
0
MMU0 (0000H-1FFFH)
MMU1 (2000H-3FFFH)
MMU2 (4000H-5FFFH)
MMU3 (6000H-7FFFH)
MMU4 (8000H-9FFFH)
20
13 12
0
External memory address
Fig. 22 An Example of MMU Switching Flow and Mapping
MMUx is selected depends on CPU address.
NOTE :
CPU can not access lower 4 k-byte of MMU0 because of
occupied by internal RAM and register file. On the other
hand, each 8 k-byte of external ROM is accessible as
DMA's address.
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