upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 444

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

17.5 Cautions for Low-Voltage Detector
(V
(1) When used as reset
(2) When used as interrupt
(1) When used as reset
(2) When used as interrupt
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LVI
In a system where the supply voltage (V
In this system, take the following actions.
<Action>
(a) Check that “supply voltage (V
(b) In a system where the supply voltage fluctuation period is long in the vicinity of the LVI detection voltage, wait
), the operation is as follows depending on how the low-voltage detector is used.
The system may be repeatedly reset and released from the reset status.
In this case, the time from release of reset to the start of the operation of the microcontroller can be arbitrarily set
by taking action (1) below.
Interrupt requests may be frequently generated. Take (b) of action (2) below.
After releasing the reset signal, wait for the supply voltage fluctuation period of each system by means of a
software counter that uses a timer, and then initialize the ports (see Figure 17-9).
using bit 0 (LVIF) of the low-voltage detection register (LVIM). Clear bit 0 (LVIIF) of interrupt request flag
register 0L (IF0L) to 0.
for the supply voltage fluctuation period, check that “supply voltage (V
LVIF flag, and clear the LVIIF flag to 0.
CHAPTER 17 LOW-VOLTAGE DETECTOR
DD
Preliminary User’s Manual U19014EJ1V0UD
) ≥ detection voltage (V
DD
) fluctuates for a certain period in the vicinity of the LVI detection voltage
LVI
)” in the servicing routine of the LVI interrupt by
DD
) ≥ detection voltage (V
LVI
)” using the