7470_M Datasheet, PDF (36/361 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER 740 FAMILY / 7470 SERIES

HARDWARE
1.8 Access area
1.8.1 Zero page (Addresses 000016 to 00FF16)
The area of 256 bytes from addresses 000016 to 00FF16 is called the zero page. The internal RAM and
the special function register (SFR) are located in this area.
To specify a memory or a register in this area, use the addressing mode shown in Table 1.8.1. In this
area, especially, it is possible to access this area in a shorter instruction cycle by using the zero addressing
mode.
1.8.2 Special page (Addresses FF0016 to FFFF16)
The area of 256 bytes from addresses FF0016 to FFFF16 is called the special page. The internal ROM
and the interrupt vector area are located in this area.
To specify a memory or subroutine in this area, use the addressing mode shown in Table 1.8.1. In this
area, especially, it is possible to jump to this area in a shorter instruction cycle by using the special page
addressing mode.
Ordinary, subroutines with high frequency of use are located in this area.
Table 1.8.1 Addressing mode accessible to each area
Addressing mode (bytes required)
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)
Zero page reference
,
,
,
,
,
,
,
,
,
,
,
,
,
—
Special page reference Other area reference
—
—
—
—
—
—
—
—
—
—
—
—
,
,
,
,
,
,
,
,
,
,
,
,
,
,
,
—
7470/7471/7477/7478 GROUP USER’S MANUAL
1-29