NEC V850E/RS1, User Manual, Page: 781 / 852

781 User’s Manual U16702EE3V2UD00
Chapter 24 Low-Voltage Detector
24.1 Functions of Low-Voltage Detector
The low-voltage detector (LVI) has following functions:
• Compares the supply voltage (V
DD
) and detected voltage (V
LVI
), and generates an internal
interrupt signal or internal reset signal when V
DD
< V
LVI
.
• The level of the supply voltage to be detected can be changed by software (in two steps).
• Interrupt or reset signal can be selected by software.
• Can operate in STOP mode.
• Operation can be stopped by software.
If the low-voltage detector is used to generate a reset signal, bit 0 (LVIRF) of the reset source flag reg-
ister (RESF) is set to 1 when the reset signal is generated., refer to
Chapter 19 ”RESET Function”
on page 739 .
24.2 Configuration of Low-Voltage Detector
Figure 23-1 shows the block diagram of the low-voltage detector.
Figure 24-1: Block Diagram of Low-Voltage Detector
LVIS0 LVION
–
+
Detection
voltage source
(V
LVI
)
V
DD
V
DD
INTLVI
Internal bus
N-ch
Low-voltage detection level
selection register (LVIS)
Low-voltage detection register
(LVIM)
LVIMD
LVIF
Internal reset signal
Low-voltage detection level selector
Selector
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