MB90340E Series
27
Note: An image of the data in the FF bank of ROM is visible in the upper part of bank 00, which makes it possible
for the C compiler to use the small memory model. The lower 16 bits of addresses in the FF bank are the
same as the lower 16 bits of addresses in the 00 bank so that tables stored in the ROM can be accessed
without using the far specifier in the pointer declaration.
For example, when the address 00C000
H
is accessed, the data at FFC000
H
in ROM is actually accessed.
The ROM area in bank FF exceeds 32 Kbytes, and its entire image cannot be shown in bank 00.
As a result, the image between FF8000
H
and FFFFFF
H
is visible in bank 00, while the image between FF0000
H
and FF7FFF
H
is visible only in bank FF.
MB90
3
42E(
S
)/
3
42CE(
S
)
MB90F
3
42E(
S
)/F
3
42CE(
S
)
MB90
3
49E(
S
)/
3
49CE(
S
)
MB90F
3
49E(
S
)/F
3
49CE(
S
)
MB90
3
41E(
S
)/
3
41CE(
S
)
MB90
3
4
8
E(
S
)/
3
4
8
CE(
S
)
MB90
3
47E(
S
)/
3
47CE(
S
)
MB90F
3
47E(
S
)/F
3
47CE(
S
)
MB90
3
46E(
S
)/
3
46CE(
S
)
MB90F
3
46E(
S
)/F
3
46CE(
S
)
FFFFFF
H
FF0000
H
FEFFFF
H
FE0000
H
FDFFFF
H
FD0000
H
FCFFFF
H
FC0000
H
0000EF
H
000000
H
00FFFF
H
007FFF
H
00
8
000
H
007900
H
00
3
FFF
H
000100
H
FFFFFF
H
FF0000
H
FEFFFF
H
FE0000
H
0000EF
H
000000
H
00FFFF
H
007FFF
H
00
8
000
H
007900
H
00
3
FFF
H
000100
H
FFFFFF
H
FF0000
H
FEFFFF
H
FE0000
H
0000EF
H
000000
H
00FFFF
H
007FFF
H
00
8
000
H
007900
H
001
8
FF
H
000100
H
FFFFFF
H
FF0000
H
FEFFFF
H
FE0000
H
0000EF
H
000000
H
00FFFF
H
007FFF
H
00
8
000
H
007900
H
000
8
FF
H
000100
H
ROM (FF
ba
nk)
ROM (FE
ba
nk)
ROM (FD
ba
nk)
ROM (FC
ba
nk)
Extern
a
l
a
cce
ss
a
re
a
ROM (im
a
ge
of FF
ba
nk)
Peripher
a
l
RAM 16 K
b
yte
s
Extern
a
l
a
cce
ss
a
re
a
Peripher
a
l
: Not
a
cce
ss
i
b
le
Extern
a
l
a
cce
ss
a
re
a
ROM (im
a
ge
of FF
ba
nk)
Peripher
a
l
RAM 16 K
b
yte
s
Extern
a
l
a
cce
ss
a
re
a
Peripher
a
l
Extern
a
l
a
cce
ss
a
re
a
ROM (im
a
ge
of FF
ba
nk)
Peripher
a
l
RAM 6 K
b
yte
s
Extern
a
l
a
cce
ss
a
re
a
Peripher
a
l
Extern
a
l
a
cce
ss
a
re
a
ROM (im
a
ge
of FF
ba
nk)
Peripher
a
l
RAM 2 K
b
yte
s
Extern
a
l
a
cce
ss
a
re
a
Peripher
a
l
ROM (FF
ba
nk)
ROM (FE
ba
nk)
ROM (FF
ba
nk)
ROM (FE
ba
nk)
ROM (FF
ba
nk)