CHAPTER 4 CPU ARCHITECTURE
User’s Manual U14826EJ5V0UD
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4.1.3 Special function register (SFR) area
Special function registers (SFRs) of on-chip peripheral hardware are allocated to the area of FF00H to FFFFH (see
Table 4-3
).
4.1.4 Data memory addressing
Each of the
µ
PD789860, 789861 Subseries is provided with a wide range of addressing modes to make memory
manipulation as efficient as possible. The data memory area (FE80H to FFFFH) can be accessed using a unique
addressing mode according to its use, such as a special function register (SFR). Figures 4-3 and 4-4 illustrate the
data memory addressing.
Figure 4-3. Data Memory Addressing (
µ
PD789860, 789861)
Special function registers (SFR)
256
×
8 bits
Internal high-speed RAM
128
×
8 bits
Reserved
Internal ROM
4,096
×
8 bits
Direct addressing
Register indirect addressing
Based addressing
SFR addressing
Short direct addressing
Reserved
EEPROM
32
×
8 bits
F F F F H
F F 0 0 H
F E F F H
F F 2 0 H
F E 1 F H
F E 8 0 H
F E 7 F H
F 8 2 0 H
F 8 1 F H
F 8 0 0 H
F 7 F F H
1 0 0 0 H
0 F F F H
0 0 0 0 H