Data Memory Addressing - NEC PD78076 User Manual

Pd78078 series; pd78078y series 8-bit single-chip microcontrollers

Table of Contents

5.1.5 Data memory addressing

Addressing is a method to specify the instruction address to be executed next and the register and memory address

to be manipulated when instructions are executed. The instruction address to be executed next is addressed by the

program counter (PC) (for details, refer to 5.3 Instruction Address Addressing).

For the addressing of the memory to be manipulated when instructions are executed, the PD78078 and 78078Y

Subseries are provided with various addressing modes for optimum addressing. Special addressing methods are

possible to meet the functions of the special function registers (SFRs) and general registers. The data memory space

is the entire 64-Kbyte space (0000H to FFFFH). Figures 5-4 to 5-6 show the data memory addressing modes.

For details of addressing, refer to 5.4 Operand Address Addressing.

Figure 5-4. Data Memory Addressing ( PD78076, 78076Y)

Special Function

Registers (SFRs)

256 x 8 bits

General Registers

Internal High-speed RAM

1024 x 8 bits

Internal Buffer RAM

Internal Expansion RAM

1024 x 8 bits

External Memory

13312 x 8 bits

Internal ROM

49152 x 8 bits

CHAPTER 5 CPU ARCHITECTURE

SFR Addressing

Short Direct

Direct Addressing

Based Addressing

Based Indexed