HD6432138SW datasheet(82/1061 Pages) RENESAS

82 / 1061 page

Section 2 CPU

Rev. 4.00 Jun 06, 2006 page 28 of 1004

REJ09B0301-0400

2.2

CPU Operating Modes

The H8S/2000 CPU has two operating modes: normal and advanced. Normal mode supports a

maximum 64-kbyte address space. Advanced mode supports a maximum 16-Mbyte total address

space (architecturally the maximum total address space is 4 Gbytes, with a maximum of 16

Mbytes for the program area and a maximum of 4 Gbytes for the data area). The mode is selected

by the mode pins of the microcontroller.

CPU operating modes

Normal mode

Advanced mode

Maximum 64 kbytes for program

and data areas combined

Maximum 16 Mbytes for

program and data areas

combined

Figure 2.1 CPU Operating Modes

(1) Normal Mode

The exception vector table and stack have the same structure as in the H8/300 CPU.

Address Space: A maximum address space of 64 kbytes can be accessed.

Extended Registers (En): The extended registers (E0 to E7) can be used as 16-bit registers, or as

the upper 16-bit segments of 32-bit registers. When En is used as a 16-bit register it can contain

any value, even when the corresponding general register (Rn) is used as an address register. If the

general register is referenced in the register indirect addressing mode with pre-decrement (@–Rn)

or post-increment (@Rn+) and a carry or borrow occurs, however, the value in the corresponding

extended register (En) will be affected.

Instruction Set: All instructions and addressing modes can be used. Only the lower 16 bits of

effective addresses (EA) are valid.

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