HD6432646 Hitachi, HD6432646 Datasheet - Page 64

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

2.2
The H8S/2600 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 a maximum 16-Mbyte program area and a maximum of 4 Gbytes for
program and data areas combined). The mode is selected by the mode pins of the microcontroller.
Note: * Not available in the H8S/2646 Series.
(1) Normal Mode (Not Available in the H8S/2646 Series)
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.
30
Higher speed
Note: * Not available in the H8S/2646 Series.
CPU operating modes
Two-bit shift instructions have been added.
Instructions for saving and restoring multiple registers have been added.
A test and set instruction has been added.
Basic instructions execute twice as fast.
CPU Operating Modes
Figure 2-1 CPU Operating Modes
Advanced mode
Normal mode*
Maximum 16-Mbytes for
program and data areas
combined
Maximum 64 kbytes, program
and data areas combined