Preliminary User’s Manual U16846EJ1V0UD
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CHAPTER 19 LOW-VOLTAGE DETECTOR
19.1 Functions of Low-Voltage Detector
The low-voltage detector (LVI) has following functions.
•
Compares supply voltage (V
DD
) and detection voltage (V
LVI
), and generates an internal interrupt signal or
internal reset signal when V
DD
< V
LVI
.
•
Detection levels (nine levels) of supply voltage can be changed by software.
•
Interrupt or reset function can be selected by software.
•
Operable in STOP mode.
When the low-voltage detector is used to reset, bit 0 (LVIRF) of the reset control flag register (RESF) is set to 1 if
reset occurs. For details of RESF, see CHAPTER 16 RESET FUNCTION.
19.2 Configuration of Low-Voltage Detector
A block diagram of the low-voltage detector is shown below.
Figure 19-1. Block Diagram of Low-Voltage Detector
LVIS1 LVIS0
LVION
−
+
Detection
voltage source
(V
LVI
)
V
DD
Internal bus
N-ch
Low-voltage detection level
selection register (LVIS)
Low-voltage detection register
(LVIM)
LVIS2
LVIS3
LVIMD
LVIF
INTLVI
Internal reset signal
4
V
DD
Low-voltage detection level selector
Selector
