Data Memory Addressing - NEC UPD789026 Series User Manual

3.1.4 Data memory addressing

The µ PD789026 Subseries provides a variety of addressing modes which take account of memory
manipulability, etc. Especially at address corresponding to data memory area (FE00H to FFFFH
Note 2
FFFFH ), particular addressing modes are possible to meet the functions of the special function registers (SFR)
and other registers. Figures 3-6 through 3-10 show the data memory addressing modes.
Notes 1. With µ PD789022 or µ PD789024
2. With µ PD789025, µ PD789026, or µ PD78F9026A
FFFFH
FF20H
FF1FH
FF00H
FEFFH
FE20H
FE1FH
FE00H
FDFFH
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1000H
0FFFH
0000H
48
CHAPTER 3 CPU ARCHITECTURE
Figure 3-6. Data Memory Addressing ( µ µ µ µ PD789022)
Special Function Registers (SFR)
256 × 8 bits
Internal High-Speed RAM
256 × 8 bits
Reserved
Internal ROM
4,096 × 8 bits
User's Manual U11919EJ3V0UM00
SFR Addressing
Short Direct
Addressing
Note 1
, FD00H to
Direct Addressing
Register Indirect
Addressing
Based Addressing