7480 datasheet(38/337 Pages) RENESAS

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7480 Group and 7481 Group User's Manual

1-21

HARDWARE

1.8.1 Zero Page (Addresses ‘000016’ through ‘00FF16’)

The area of 256 bytes from addresses ‘000016’ through ‘00FF16’ is called the zero page. The internal RAM

and the special function registers (SFR) are located in this area.

The addressing modes shown in Table 1.8.1 are used to specify memory or registers in this area. In the

mode listed, the zero page addressing mode can be used to access this area by shorter instruction cycles.

1.8.2 Special Page (Addresses ‘FF0016’ through ‘FFFF16’)

The area of 256 bytes from addresses ‘FF0016’ through ‘FFFF16’ is called the special page. The internal

ROM and the interrupt vector area are located in this area.

The addressing modes shown in Table 1.8.1 are used to specify memory or subroutines in this area. In

the mode listed, the special page addressing mode can be used to jump to this area by shorter instruction

cycles.

Ordinary, frequently used subroutines are located in this area.

Table 1.8.1 Addressing Mode Accessible to Each Area

1.8 Access Area

Addressing Mode

(Required Bytes)

Zero Page (2)

Zero Page Indirect (2)

Zero Page X (2)

Zero Page Y (2)

Zero Page Bit (2)

Zero Page Bit Relative (3)

Absolute (3)

Absolute X (3)

Absolute Y (3)

Relative (2)

Indirect (3)

Indirect X (2)

Indirect Y (2)

Special Page (2)

Reference to Other Areas

–

Reference to Special Page

–

Reference to Zero Page

–

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