Data Memory Addressing; Data Memory Addressing ( Μ Pd789425, 789435) - NEC UPD789426 Series User Manual

3.1.4 Data memory addressing

µ
The PD789426, 789436, 789446, and 789456 Subseries are provided with a variety of addressing modes to
make memory manipulation as efficient as possible. At the addresses corresponding to data memory area (FD00H to
FFFFH) especially, specific addressing modes that correspond to the particular function an area, such as the special
function registers are available. Figures 3-7 through 3-12 show the data memory addressing modes.
FFFFH
Special function registers (SFRs)
FF20H
FF1FH
FF00H
FEFFH
Internal high-speed RAM
FE20H
FE1FH
FD00H
FCFFH
FA05H
FA04H
LCD display RAM
FA00H
F9FFH
3000H
2FFFH
0000H
54
CHAPTER 3 CPU ARCHITECTURE
Figure 3-7. Data Memory Addressing (
SFR addressing
256 × 8 bits
512 × 8 bits
Reserved
5 × 4 bits
Reserved
Internal ROM
12288 × 8 bits
User's Manual U15075EJ2V1UD
µ
PD789425, 789435)
Short direct
addressing
Direct addressing
Register indirect
addressing
Based addressing