
MB90455 Series
15
s
s MEMORY MAP
MB90455 series allows specifying a memory access mode “single chip mode.”
1.
Memory allocation of MB90455
MB90455 series model has 24-bit wide internal address bus and up to 24-bit bus of external address bus.
A maximum of 16 Mbyte memory space of external access memory is accessible.
2.
Memory map
Note : When internal ROM is operating, F2MC-16LX allows viewing ROM data image on FF bank at upper-level of
00 bank. This function is called “mirroring ROM,” which allows effective use of C compiler small model.
F2MC-16LX assigns the same low order 16-bit address to FF bank and 00 bank, which allows referencing
table in ROM without specifying “far” using pointer.
For example, when accessing to “00C000H”, ROM data at “FFC000H” is accessed actually. However, because
ROM area of FF bank exceeds 48 Kbytes, viewing all areas is not possible on 00 bank image. Because ROM
data of “FF4000H” to “FFFFFFH” is viewed on “004000H” to “00FFFFH” image, store a ROM data table in area
“FF4000H” to “FFFFFFH.”
FFFFFF H
FE0000 H
010000 H
003800 H
004000 H
000100 H
0000C0 H
000000 H
FF0000 H
(with ROM mirroring
function available)
Peripheral
RAM area
Register
Extension IO
area
ROM area
(FF bank image)
ROM area
Address #1*1
: Internal access memory
: Access disallowed
*1 : Addresses #1 and #3 are product-specific.
*2 : On MB90F455 (S) /F456 (S) /F457 (S) , 455 (S) /456 (S) /457 (S) , to read “FE0000H” to
“FEFFFFH” is to read out “FF0000H” to “FFFFFFH”.
ROM area*2
(with ROM mirroring
function not available)
Peripheral
RAM area
Register
Extension IO
area
ROM area
ROM area*2
Product
Address #1*1
Address #2*1
MB90F455 (S) /455 (S)
000900H
FFA000H
MB90F456 (S) /456 (S)
000900H
FF8000H
MB90F457 (S) /457 (S)
000900H
FF0000H
MB90V495G
001900H
Address #2*1