Special Function Register (Sfr) Area; Data Memory Addressing - NEC 78K0 Series User Manual

(2) Internal expansion RAM
Part Number
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PD78F0531
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PD78F0532
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PD78F0533
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PD78F0534
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PD78F0535
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PD78F0536
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PD78F0537, 78F0537D
The internal expansion RAM can also be used as a normal data area similar to the internal high-speed RAM, as
well as a program area in which instructions can be written and executed.
The internal expansion RAM cannot be used as a stack memory.

3.1.4 Special function register (SFR) area

On-chip peripheral hardware special function registers (SFRs) are allocated in the area FF00H to FFFFH (see
Table 3-6 Special Function Register List in 3.2.3 Special function registers (SFRs)).
Caution Do not access addresses to which SFRs are not assigned.

3.1.5 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.
Several addressing modes are provided for addressing the memory relevant to the execution of instructions for the
78K0/KE2, 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. Figures 3-9 to 3-15 show correspondence between data memory and addressing. For details of
each addressing mode, see 3.4 Operand Address Addressing.
CHAPTER 3 CPU ARCHITECTURE
Table 3-5. Internal Expansion RAM Capacity
1024 × 8 bits (F400H to F7FFH)
2048 × 8 bits (F000H to F7FFH)
4096 × 8 bits (E800H to F7FFH)
6144 × 8 bits (E000H to F7FFH)
Preliminary User's Manual U17260EJ3V1UD
Internal Expansion RAM
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