33
CHAPTER 2 CPU
2.5
Bank Addressing Types
In the bank method, the 16-Mbyte space is divided into 256 64-Kbyte banks. The
following five bank registers are used to specify the banks corresponding to each
space:
• Program counter bank register (PCB)
• Data bank register (DTB)
• User stack bank register (USB)
• System stack bank register (SSB)
• Additional data bank register (ADB)
■
Bank Addressing Types
●
Program counter bank register (PCB)
The 64-Kbyte bank specified by the PCB is called a program (PC) space. The PC space contains instruction
codes, vector tables, and immediate value data, for example.
●
Data bank register (DTB)
The 64-Kbyte bank specified by the DTB is called a data (DT) space. The DT space contains readable/
writable data, and control/data registers for internal and external resources.
●
User stack bank register (USB)/system stack bank register (SSB)
The 64-Kbyte bank specified by the USP or SSP is called a stack (SP) space. The SP space is accessed
when a stack access occurs during a push/pop instruction or interrupt register saving. The S flag in the
condition code register determines the stack space to be accessed.
●
Additional data bank register (ADB)
The 64-Kbyte bank specified by the ADB is called an additional (AD) space. The AD space, for example,
contains data that cannot fit into the DT space.
Table 2.5-1 lists the default spaces used in each addressing mode, which are pre-determined to improve
instruction coding efficiency. To use a non-default space for an addressing mode, specify a prefix code
corresponding to a bank before the instruction. This enables access to the bank space corresponding to the
specified prefix code.
After reset, the DTB, USB, SSB, and ADB are initialized to "00
H
". The PCB is initialized to a value
specified by the reset vector. After reset, the DT, SP, and AD spaces are allocated in bank "00
H
" (000000
H
to 00FFFF
H
), and the PC space is allocated in the bank specified by the reset vector.
Содержание MB90390 Series
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Страница 17: ...xiii APPENDIX D List of Interrupt Vectors 690 INDEX 695 ...
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Страница 132: ...104 CHAPTER 5 CLOCKS ...
Страница 152: ...124 CHAPTER 6 CLOCK MODULATOR ...
Страница 210: ...182 CHAPTER 11 TIME BASE TIMER ...
Страница 218: ...190 CHAPTER 12 WATCHDOG TIMER ...
Страница 264: ...236 CHAPTER 14 16 BIT RELOAD TIMER WITH EVENT COUNT FUNCTION ...
Страница 274: ...246 CHAPTER 15 WATCH TIMER ...
Страница 306: ...278 CHAPTER 17 DTP EXTERNAL INTERRUPTS ...
Страница 338: ...310 CHAPTER 18 8 10 BIT A D CONVERTER ...
Страница 364: ...336 CHAPTER 19 UART0 UART1 ...
Страница 398: ...370 CHAPTER 20 UART2 UART3 Figure 20 5 2 ORE Set Timing Receive data RDRF ORE ...
Страница 432: ...404 CHAPTER 20 UART2 UART3 ...
Страница 482: ...454 CHAPTER 22 SERIAL I O ...
Страница 560: ...532 CHAPTER 24 STEPPING MOTOR CONTROLLER ...
Страница 582: ...554 CHAPTER 27 ROM MIRRORING MODULE ...
Страница 632: ...604 CHAPTER 29 EXAMPLES OF SERIAL PROGRAMMING CONNECTION ...
Страница 722: ...694 APPENDIX ...
Страница 723: ...695 INDEX The index follows on the next page This is listed in alphabetic order ...
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