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CHAPTER 6 LOW POWER CONSUMPTION MODE
6.4
CPU Intermittent Operation Mode
CPU intermittent operation mode is used for intermittent operation of the CPU while
external buses and peripheral functions continue to operate at high speed. Its purpose
is to reduce power consumption.
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CPU Intermittent Operation Mode
CPU intermittent operation mode halts the supply of the clock to the CPU for a certain period. The halt
occurs after the execution of every instruction that accesses a register, internal memory (ROM and RAM),
I/O, peripheral functions and the external bus. Internal bus cycle activation is therefore delayed. While a
steady rate of peripheral clock pulses are supplied to the peripheral functions, the rate of CPU execution is
reduced, enabling processing with low power consumption.
•
The CG1 and CG0 bits of the low power consumption mode control register (LPMCR) are used to select
the number of clock pulses per halt cycle of the clock supplied to the CPU.
•
External bus operation uses the same clock as that used for peripheral functions.
•
Instruction execution time in CPU intermittent mode can be calculated. A correction value should be
obtained by multiplying the number of times instructions that access a register, internal memory,
internal peripheral functions, and the external bus are executed by the number of clock pulses per halt
cycle. Add this correction value to the normal execution time.
Figure 6.4-1 shows the operating clock pulses during CPU intermittent operation mode.
Figure 6.4-1 Clock Pulses during CPU Intermittent Operation
CPU clock
Intermittent operation halt cycle
Internal bus activation cycle
Peripheral clock
One instruction
execution cycle
Содержание MB90460 Series
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Страница 83: ...64 CHAPTER 3 CPU ...
Страница 95: ...76 CHAPTER 4 RESET ...
Страница 107: ...88 CHAPTER 5 CLOCK ...
Страница 131: ...112 CHAPTER 6 LOW POWER CONSUMPTION MODE ...
Страница 175: ...156 CHAPTER 7 INTERRUPT ...
Страница 181: ...162 CHAPTER 8 MODE SETTING ...
Страница 223: ...204 CHAPTER 9 I O PORT ...
Страница 237: ...218 CHAPTER 10 TIME BASE TIMER ...
Страница 247: ...228 CHAPTER 11 WATCHDOG TIMER ...
Страница 275: ...256 CHAPTER 12 16 BIT RELOAD TIMER ...
Страница 373: ...354 CHAPTER 14 MULTI FUNCTIONAL TIMER ...
Страница 485: ...466 CHAPTER 16 PWC Timer ...
Страница 531: ...512 CHAPTER 17 UART ...
Страница 559: ...540 CHAPTER 19 DELAYED INTERRUPT GENERATOR MODULE ...
Страница 589: ...570 CHAPTER 20 8 10 BIT A D CONVERTER ...
Страница 601: ...582 CHAPTER 21 ROM CORRECTION FUNCTION ...
Страница 633: ...614 CHAPTER 23 512K 1024K BIT FLASH MEMORY ...
Страница 645: ...626 CHAPTER 24 EXAMPLE OF F2 MC 16LX MB90F462 F462A F463A CONNECTION FOR SERIAL WRITING ...
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Страница 716: ...697 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
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