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CHAPTER 3 CPU ARCHITECTURE
3.1.4 Data memory addressing
Addressing refers to the method of specifying the address of the instruction to be executed next or the address
of the register or memory relevant to the execution of instructions.
The address of an instruction to be executed next is addressed by the program counter (PC) (for details, see 3.3
Instruction Address Addressing).
Several addressing modes are provided for addressing the memory relevant to the execution of instructions for
the
µ
PD780973 Subseries, based on operability and other considerations. For areas containing data memory in
particular, special addressing methods designed for the functions of special function registers (SFR) and general-
purpose registers are available for use. Data memory addressing is illustrated in Figures 3-3 and 3-4. For the details
of each addressing mode, see 3.4 Operand Address Addressing.
Figure 3-3. Data Memory Addressing (
µ
PD780973(A))
0000H
General Registers
32
×
8 bits
Internal ROM
24576
×
8 bits
LCD Display RAM
20
×
4 bits
EEPROM
256
×
8 bits
6000H
5FFFH
FA59H
FA58H
FA6DH
FA6CH
FEE0H
FEDFH
FF00H
FEFFH
FFFFH
Internal High-speed RAM
768
×
8 bits
Reserved
FC00H
FBFFH
FF20H
FF1FH
FE20H
FE1FH
Special Function
Registers (SFRs)
256
×
8 bits
SFR Addressing
Register Addressing
Short Direct
Addressing
Direct Addressing
Register Indirect
Addressing
Based Addressing
Based Indexed
Addressing
FA00H
F9FFH
Reserved
F900H
F8FFH
Reserved
Summary of Contents for mPD780973 Series
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