MB90980 Datasheet, PDF (15/48 Pages) Fujitsu Component Limited. – 16-bit Proprietary Microcontroller

■ MEMORY MAP
FFFFFFH
Address #1
FC0000H
010000H
Address #2
MB90980 Series
Single chip
ROM area
ROM area,
Image of FF bank
Address #3
RAM
Register
000100H
0000D0H
000000H
Peripheral
Internal access
No access
Model
Address #1
Address #2
Address #3
MB90F983
MB90982
FC0000H *¹
FD0000H*²
004000H or 008000H,
selected by the MS bit in
the ROMM register
003100H
002900H
*1 : No memory cells from FC0000H to FC7FFFH and FE0000H to FE7FFFH.
*2 : No memory cells from FE0000H to FEFFFFH. The upper part of the 00 bank is set up to mirror the image of
FF bank ROM, to enable efficient use of small model C compilers. Because the lower 16-bit address of the FF
bank and the lower 16-bit address of the 00 bank is the same, enabling reference to tables in ROM without
the “far” pointer declaration.
For example, in accessing address 00C000H it is actually the contents of ROM at FFC000H that are accessed.
If the MS bit in the ROMM register is set to “0”, the ROM area in the FF bank will exceed 48 Kbytes and it is
not possible to reflect the entire area in the image in the 00 bank. Therefore the image from FF4000H to FFFFFFH
is reflected in the 00 bank and the area from FF0000H to FF3FFFH can be seen in the FF bank only.
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