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M16C/64A Group
8.7
Oscillator Stop/Restart Detect Function
This function detects a stop/restart of the main clock oscillator. The oscillator stop/restart detect function
can be enabled and disabled with the CM20 bit in the CM2 register.
A reset or oscillator stop/restart detect interrupt is generated when an oscillator stop or restart is detected.
Set the CM27 bit in the CM2 register to select the reset or interrupt.
Table 8.6 lists Oscillator Stop/Restart Detect Function Specifications.
Table 8.6
Oscillator Stop/Restart Detect Function Specifications
Item
Oscillator stop detectable clock and
frequency bandwidth
Enabling condition for the oscillator
stop/restart detect function
Operation when oscillator stop/restart
detected
8.7.1
Operation When CM27 Bit is 0 (Oscillator Stop Detect Reset)
When main clock stop is detected while the CM20 bit is 1 (oscillator stop/restart detect function
enabled), the MCU is initialized, and then stops (oscillator stop reset). Refer to 4. "Special Function
Registers (SFRs)" and 6. "Resets".
The status can be cancelled by a hardware reset or a voltage monitor 0 reset. The MCU can also be
initialized and stopped when a restart is detected, but do not use the MCU in this manner. During main
clock stop, do not set the CM20 bit to 1 and the CM27 bit to 0.
R01UH0136EJ0210 Rev.2.10
Jul 31, 2012
f(XIN) ≥ 2 MHz
Set the CM20 bit to 1 (enabled)
When CM27 bit is 0: Oscillator stop detect reset generated
When CM27 bit is 1: Oscillator stop/restart detect interrupt
generated
8. Clock Generator
Specification
Page 102 of 800
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