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R01UH0336EJ0102 Rev.1.02
Page 301 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 8 Reset Controller
8.4.2
Operation
(1)
POF Detection
Monitoring of the power supply voltage for the internal regulator leads to
setting of the power-on flag (the POF.POF bit) if the power supply voltage for
the internal regulator falls below the prescribed detection voltage (both when
the voltage is supplied and when the voltage is cut off).
Note
The state (operating or stopped) is not specifiable by software.
Caution
When the power supply voltage for the internal regulator (VDD) falls below the
POF detection voltage, an external reset must be input.
Wait more than 6 ms before de-asserting the external reset signal after
individual power supply voltage exceeds the lower limit on guaranteed range of
operating voltage.
Figure 8-5
Example of POF Operations
Time
Power supply
voltage
POF detection level
POF bit
4.5 V
Delay
Delay
Caution
Software can be used to clear the POF bit.