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LOW VOLTAGE AND CPU OPERATION DETECTION RESET CIRCUIT
24.4 Operation of Low Voltage and CPU Operation Detection Reset Circuit
The low-voltage detection function causes an internal reset when it detects that the power supply voltage
has fallen below the set point. The CPU operation detection function causes an internal reset when the
counter is not cleared at regular intervals. When a low voltage or CPU software nullfunction or hardware
upset is detected and causes an internal reset, the value of this register is not assured. After the low-voltage
reset is cancelled, the reset sequence is executed after the operation stabilization wait time has elapsed and
then the program restarts at the address specified for the reset vector.
n Operation of low-voltage detection reset circuit
The low-voltage detection reset circuit waits for the operation stabilization wait time and then starts low-
voltage detection.
Table 24-4 gives the operation stabilization wait time.
n Operation of CPU operation detection reset circuit
After the reset is cancelled, the CPU operation detection reset circuit starts the CPU operation detection
without requiring the operation stabilization wait time.
Note:
Since the low-voltage reset circuit is always operating, current is consumed even in the sleep or
stop mode.
Table 24-4 Operation Stabilization Wait Time
Operation Stabilization Wait Time
2
24-7
17
/Fc
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