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CHAPTER 26 CLOCK SUPERVISOR
26.4
Operations of Clock Supervisor
This section describes the operations of the clock supervisor.
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Operations of Clock Supervisor
The clock supervisor monitors the main clock and sub clock oscillations. If main clock and sub clock
oscillations have halted, the device switches to an CR clock and generates a reset.
The following describes the operation in each clock mode.
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Main clock oscillation halt in main clock mode
The clock supervisor detect that main clock oscillation has halted, if no rising edge is detected on the main
clock for 4 CR clock cycles in main clock mode.
If a main clock halt is detected, a reset is generated and the main clock switches to the CR clock.
The clock supervisor may detect incorrectly, if main clock is a low speed (longer than 4 CR clock cycles).
It results from using the CR clock for detecting that main clock oscillation have halted.
The clock supervisor does not detect the main clock during stop mode.
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Sub clock oscillation halt in main clock mode (only on dual clock products)
In main clock mode, the condition used to detect the sub clock oscillation as having halted is that no rising
edge is detected on the sub clock for 32 CR clock cycles.
Although no reset is generated immediately if a sub clock halt is detected in main clock mode, the sub
clock switches to CR clock divided by two.
A reset can be generated when the device switches from main clock mode to sub clock mode with a sub clock
oscillation halt detected, by setting the SRST bit in the clock supervisor control register (CSVCR).
Because the CR clock is used to detect whether the sub clock has halted, a sub clock halt may be detected if
the sub clock is set to a low speed (period longer than 32 CR clock cycles).
The clock supervisor does not detect the sub clock during stop mode.
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Sub clock oscillation halt in sub clock mode (only on dual clock products)
In sub clock mode, the condition used to detect the sub clock oscillation as having halted is that no rising
edge is detected on the sub clock for 34 CR clock cycles.
If a sub clock halt is detected, a reset is generated and the device enters main clock mode. In this case, the
sub clock switches to CR clock divided by two.
As the CR clock is used to detect whether the sub clock has halted, a sub clock halt may be detected if the
sub clock is set to a low speed (period longer than 32 CR clock cycles).
The clock supervisor does not detect the sub clock during the stop mode.
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Main clock oscillation halt in sub clock mode (only on dual clock products)
In sub clock mode, the main clock oscillation remains halted and is therefore not detected by the clock
supervisor.
Содержание F2 MC-8FX Family
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Страница 30: ...16 CHAPTER 1 DESCRIPTION 1 FPT 64P M23 FPT 64P M24 2 For the I O circuit type refer to 1 8 I O Circuit Type ...
Страница 34: ...20 CHAPTER 1 DESCRIPTION ...
Страница 35: ...21 CHAPTER 2 HANDLING DEVICES This chapter gives notes on using 2 1 Device Handling Precautions ...
Страница 38: ...24 CHAPTER 2 HANDLING DEVICES ...
Страница 39: ...25 CHAPTER 3 MEMORY SPACE This chapter describes memory space 3 1 Memory Space 3 2 Memory Map ...
Страница 43: ...29 CHAPTER 4 MEMORY ACCESS MODE This chapter describes the memory access mode 4 1 Memory Access Mode ...
Страница 56: ...42 CHAPTER 5 CPU ...
Страница 73: ...59 CHAPTER 6 CLOCK CONTROLLER ...
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Страница 104: ...90 CHAPTER 7 RESET ...
Страница 105: ...91 CHAPTER 8 INTERRUPTS This chapter explains the interrupts 8 1 Interrupts ...
Страница 174: ...160 CHAPTER 10 TIMEBASE TIMER ...
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Страница 218: ...204 CHAPTER 13 WATCH PRESCALER ...
Страница 257: ...243 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
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Страница 382: ...368 CHAPTER 21 UART SIO DEDICATED BAUD RATE GENERATOR ...
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Страница 430: ...416 CHAPTER 23 10 BIT A D CONVERTER ...
Страница 476: ...462 CHAPTER 24 LCD CONTROLLER ...
Страница 482: ...468 CHAPTER 25 LOW VOLTAGE DETECTION RESET CIRCUIT ...
Страница 494: ...480 CHAPTER 26 CLOCK SUPERVISOR ...
Страница 507: ...493 CHAPTER 27 REAL TIME CLOCK ...
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Страница 536: ...522 CHAPTER 28 256 KBIT FLASH MEMORY ...
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Страница 564: ...550 CHAPTER 29 EXAMPLE OF SERIAL PROGRAMMING CONNECTION ...
Страница 595: ...581 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
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Страница 599: ...585 Pin Function Index V2 LCD power supply driving pin 2 439 V3 LCD power supply driving pin 3 439 ...
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