Rom Mirror Function Selection Register (Romm) - Fujitsu F2MC-16LX Hardware Manual

22.2 ROM Mirror Function Selection Register (ROMM)

When "1" is written in the MI bit of the ROM mirror function selection register (ROMM),
the ROM data of bank FF can be read in bank 00. When "0" is written, this function is
invalid.
■ ROM Mirror Function Selection Register (ROMM)
Figure 22.2-1 ROM Mirror Function Selection Register (ROMM)
ROM mirror function
selection module
Address:
00006F
Read/write
Initial value
Note:
Do not access this register while the operation in addresses 004000
ongoing.
[bit8] MI
When "1" is written in the MI bit, ROM data in bank FF can be read in bank 00. When "0" is
written in the MI bit, this function does not work in bank 00. This bit is writable only.
Figure 22.2-2 shows the memory space in the single-chip mode. Figure 22.2-3 shows the
memory space in the internal ROM external bus mode.
Note:
Since only addresses FF4000
in bank 00 when the ROM mirror function is activated, address FF3FFF
addresses in ROM are not mirrored in the 00 bank even if the ROM mirror function is set with
their values.
Table 22.2-1 Memory Space Address
Address 1
Address 2
15 14 13
bit
H
(-) (-) (-)
(-) (-) (-)
H
MB90552A/B
FF0000
H
000900
H
22.2 ROM Mirror Function Selection Register (ROMM)
12 11 10
(-) (-) (-)
(-) (-) (-)
to FFFFFF are mirrored to addresses 004000
H
MB90553A/B
FE0000
H
001100
H
9
8
ROMM
MI
(-) (W)
(-) (1)
to 00FFFF
H
to 00FFFF
H
and preceding
H
MB90P553A MB90V550A
FE0000 FE0000
H
001100 001900
H
are
H
H
H
H
339