upd78f0124hgba1-8et-a Renesas Electronics Corporation., upd78f0124hgba1-8et-a Datasheet - Page 368

• Manufacturer Part Number: upd78f0124hgba1-8et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

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21.1 Functions of Power-on-Clear Circuit
368
The power-on-clear circuit (POC) has the following functions.
• Generates internal reset signal at power on.
• Compares supply voltage (V
Cautions 1. If an internal reset signal is generated in the POC circuit, the reset control flag register
Remark This product incorporates multiple hardware functions that generate an internal reset signal. A flag that
when V
DD
indicates the reset cause is located in the reset control flag register (RESF) for when an internal reset
signal is generated by the watchdog timer (WDT), low-voltage-detection (LVI) circuit, or clock monitor.
RESF is not cleared to 00H and the flag is set to 1 when an internal reset signal is generated by WDT,
LVI, or the clock monitor.
For details of the RESF, see CHAPTER 19 RESET FUNCTION.
2. The supply voltage is V
3. The supply voltage is V
< V
(RESF) is cleared to 00H.
is used, but be sure to use the standard products and (A) grade products in a voltage range
of 2.2 to 5.5 V because the detection voltage (V
sure to use the (A1) grade products in a voltage range of 2.25 to 5.5 V because the detection
voltage (V
POC
.
POC
) of the POC circuit is 2.0 to 2.25 V.
CHAPTER 21 POWER-ON-CLEAR CIRCUIT
DD
) and detection voltage (V
DD
DD
= 2.0 to 5.5 V when the internal oscillation clock or subsystem clock
User’s Manual U16962EJ3V0UD
= 2.0 to 5.5 V when the internal oscillation clock is used, but be
POC
= 2.1 V ±0.1 V), and generates internal reset signal
POC
) of the POC circuit is 2.1 V ±0.1 V.