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2 rom mirroring function select register (romm), Rom mirroring function select register (romm) – FUJITSU F2MCTM-16LX User Manual

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CHAPTER 23 ROM MIRRORING MODULE

23.2

ROM Mirroring Function Select Register (ROMM)

The ROM mirroring function select register (ROMM) enables or disables the ROM
mirroring function. When the ROM mirroring function is enabled, ROM data in the FF
bank can be read by access to the 00 bank.

ROM Mirroring Function Select Register (ROMM)

Figure 23.2-1 ROM Mirroring Function Select Register (ROMM)

Note:

While the ROM area at addresses "008000

H

" to "00FFFF

H

" is being used, access to the ROM mirroring

function select register (ROMM) is prohibited.

X X X X X X X 1

B

12

13

11

10

9

8

15

14

W

X

W

00006F

H

MI

Reset value

bit8

MI

ROM mirroring function select bit

0

ROM mirroring function disabled

1

ROM mirroring function enabled

Address

: Write only

: Indeterminate

: Undefined

: Reset value

Table 23.2-1 Functions of ROM Mirroring Function Select Register (ROMM)

Bit Name

Function

bit8

MI:
ROM mirroring
function select bit

This bit enables or disables the ROM mirroring function.
When set to 0: Disables ROM mirroring function
When set to 1: Enables ROM mirroring function

When the ROM mirroring function is enabled (MI = 1), data
at ROM addresses "FF8000

H

" to "FFFFFF

H

" can be read by

accessing addresses "008000

H

" to "00FFFF

H

".

bit9
to
bit15

Undefined bits

Read: Value is undefined.
Write: No effect