Section 2 CPU
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REJ09B0286-0300
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 address space.
The mode is selected by the LSI's mode pins.
2.2.1
Normal Mode
The exception vector table and stack have the same structure as in the H8/300 CPU in normal
mode.
•
Address space
Linear access to a maximum address space of 64 kbytes is possible.
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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 extended register 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 general register Rn is
referenced in the register indirect addressing mode with pre-decrement (@–Rn) or post-
increment (@Rn+) and a carry or borrow occurs, the value in the corresponding extended
register (En) will be affected.)
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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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Exception vector table and memory indirect branch addresses
In normal mode, the top area starting at H'0000 is allocated to the exception vector table. One
branch address is stored per 16 bits. The exception vector table in normal mode is shown in
figure 2.1. For details of the exception vector table, see section 4, Exception Handling.
The memory indirect addressing mode (@@aa:8) employed in the JMP and JSR instructions
uses an 8-bit absolute address included in the instruction code to specify a memory operand
that contains a branch address. In normal mode, the operand is a 16-bit (word) operand,
providing a 16-bit branch address. Branch addresses can be stored in the top area from H'0000
to H'00FF. Note that this area is also used for the exception vector table.
•
Stack structure
In normal mode, when the program counter (PC) is pushed onto the stack in a subroutine call
in normal mode, and the PC and condition-code register (CCR) are pushed onto the stack in
exception handling, they are stored as shown in figure 2.2. The extended control register
(EXR) is not pushed onto the stack. For details, see section 4, Exception Handling.
Summary of Contents for H8S/2158
Page 10: ...Rev 3 00 Jan 25 2006 page viii of lii...
Page 36: ...Rev 3 00 Jan 25 2006 page xxxiv of lii B Product Lineup 863 C Package Dimensions 864 Index 865...
Page 47: ...Rev 3 00 Jan 25 2006 page xlv of lii Appendix Figure C 1 Package Dimensions TBP 112A 864...
Page 54: ...Rev 3 00 Jan 25 2006 page lii of lii...
Page 70: ...Section 1 Overview Rev 3 00 Jan 25 2006 page 16 of 872 REJ09B0286 0300...
Page 118: ...Section 3 MCU Operating Modes Rev 3 00 Jan 25 2006 page 64 of 872 REJ09B0286 0300...
Page 126: ...Section 4 Exception Handling Rev 3 00 Jan 25 2006 page 72 of 872 REJ09B0286 0300...
Page 198: ...Section 6 Bus Controller Rev 3 00 Jan 25 2006 page 144 of 872 REJ09B0286 0300...
Page 326: ...Section 10 8 Bit PWM Timer PWM Rev 3 00 Jan 25 2006 page 272 of 872 REJ09B0286 0300...
Page 440: ...Section 15 Watchdog Timer WDT Rev 3 00 Jan 25 2006 page 386 of 872 REJ09B0286 0300...
Page 606: ...Section 17 I 2 C Bus Interface IIC Rev 3 00 Jan 25 2006 page 552 of 872 REJ09B0286 0300...
Page 742: ...Section 19 Multimedia Card Interface MCIF Rev 3 00 Jan 25 2006 page 688 of 872 REJ09B0286 0300...
Page 750: ...Section 21 D A Converter Rev 3 00 Jan 25 2006 page 696 of 872 REJ09B0286 0300...
Page 768: ...Section 22 A D Converter Rev 3 00 Jan 25 2006 page 714 of 872 REJ09B0286 0300...
Page 770: ...Section 23 RAM Rev 3 00 Jan 25 2006 page 716 of 872 REJ09B0286 0300...
Page 824: ...Section 26 Clock Pulse Generator Rev 3 00 Jan 25 2006 page 770 of 872 REJ09B0286 0300...
Page 844: ...Section 27 Power Down Modes Rev 3 00 Jan 25 2006 page 790 of 872 REJ09B0286 0300...
Page 878: ...Section 28 List of Registers Rev 3 00 Jan 25 2006 page 824 of 872 REJ09B0286 0300...
Page 926: ...Index Rev 3 00 Jan 25 2006 page 872 of 872 REJ09B0286 0300...