Preliminary User’s Manual U19014EJ1V0UD
430
CHAPTER 16 POWER-ON-CLEAR CIRCUIT
16.1 Functions of Power-on-Clear Circuit
The power-on-clear circuit (POC) has the following functions.
•
Generates internal reset signal at power on.
In the 2.7 V/1.59 V POC mode (option byte: POCMODE = 1)
Note
, the reset signal is released when the supply
voltage (V
DD
) exceeds 2.7 V
±
0.2 V.
•
Compares supply voltage (V
DD
) and detection voltage (V
POC
= 1.59 V
±
0.15 V), generates internal reset signal
when V
DD
< V
POC
, and releases reset when V
DD
≥
V
DDPOC
.
Note
For
the
µ
PD78F0730, be sure to set the 2.7 V/1.59 V POC mode by using the option byte (POCMODE = 1).
Caution If an internal reset signal is generated in the POC circuit, the reset control flag register (RESF)
is cleared to 00H.
Remark
This product incorporates multiple hardware functions that generate an internal reset signal. A flag
that indicates the reset source is located in the reset control flag register (RESF) for when an internal
reset signal is generated by the watchdog timer (WDT) or low-voltage-detector (LVI). RESF is not
cleared to 00H and the flag is set to 1 when an internal reset signal is generated by WDT or LVI.
For details of RESF, see
CHAPTER 15 RESET FUNCTION
.
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