24

CHAPTER 1 OVERVIEW
1.7 Memory Address Space

The logical address space of the FR series consists of 4 gigabytes (232 addresses) and

the CPU accesses them linearly.

Memory map

Figure 1.7.1 shows the memory address space of the MB91F109.

Figure 1.7-1 MB91F109 Memory Map

Note:

The CPU can access no external areas in single-chip mode.

To enable the CPU to access an external area, se lect internal ROM ex ternal bus mode using

the mode register.

0000 0000
H
I/O I/O I/O
0000 0400
H
I/O I/O I/O
0000 0800
H
0000 1000
H
0000 1800
H
0001 0000
H
0001 0000
H
0008 0000
H
000C 0000
H
000C 0800
H
FLASH ROM FLASH ROM
254KB 254KB
0010 0000
H
FFFF FFFF
H
FFFF FFFF
H
External-ROM
external-bus mode
Internal-ROM
external-bus mode Single-chip mode
Direct
addressing
area
I/O map
(See Appendix A.)
Access inhibited Access inhibited Access inhibited
Access inhibited Access inhibited Access inhibited
Internal RAM 2 KB Internal RAM 2 KB Internal RAM 2 KB
Internal RAM 2 KB Internal RAM 2 KB
Access inhibited Access inhibited
Access inhibited
Access inhibited
External area
External area
External area