Renesas RL78/G1P Hardware User Manual page 645

RL78/G1P
19.1 Functions of Voltage Detector
The voltage detector (LVD) has the following functions.
 The LVD circuit compares the supply voltage (V
internal reset or internal interrupt signal.
 The detection level for the power supply detection voltage (V
one of four levels (for details, see CHAPTER 22 OPTION BYTE).
 Operable in STOP mode.
 After power is supplied, the reset state must be retained until the operating voltage becomes in the range defined in
27.4 AC Characteristics. This is done by utilizing the voltage detection circuit or controlling the externally input
reset signal. After the power supply is turned off, this LSI should be placed in the STOP mode, or placed in the reset
state by utilizing the voltage detection circuit or controlling the externally input reset signal before the voltage falls
below the operating range. The range of operating voltage varies with the setting of the user option byte (000C2H).
 The following three operation modes can be selected by using the option byte.
(a) Interrupt & reset mode (option byte LVIMDS1, LVIMDS0 = 1, 0)
For the two detection voltages selected by the option byte 000C1H, the high-voltage detection level (V
used for generating interrupts and ending resets, and the low-voltage detection level (V
resets.
(b) Reset mode (option byte LVIMDS1, LVIMDS0 = 1, 1)
The detection voltage (V
(c) Interrupt mode (option byte LVIMDS1, LVIMDS0 = 0, 1)
The detection voltage (V
Two detection voltages (V
the reset mode and interrupt mode.
The reset and interrupt signals are generated as follows according to the option byte (LVIMDS0, LVIMDS1) selection.
Interrupt & Reset Mode
(LVIMDS1, LVIMDS0 = 1, 0)
Generates an internal interrupt signal
when V < V , and an internal reset
DD LVDH
when V < V .
DD LVDL
Releases the reset signal when V
V .
LVH
While the voltage detector is operating, whether the supply voltage is more than or less than the detection level can be
checked by reading the voltage detection flag (LVIF: bit 0 of the voltage detection register (LVIM)).
Bit 0 (LVIRF) of the reset control flag register (RESF) is set to 1 if reset occurs. For details of the RESF register, see
CHAPTER 17 RESET FUNCTION.
R01UH0895EJ0100 Rev.1.00
Nov 29, 2019
CHAPTER 19 VOLTAGE DETECTOR
DD
) selected by the option byte 000C1H is used for triggering and ending resets.
LVD
) selected by the option byte 000C1H is used for generating interrupts/reset release.
LVD
, V ) can be specified in the interrupt & reset mode, and one (V
LVDH LVDL
Reset Mode
(LVIMDS1, LVIMDS0 = 1, 1)
Generates an internal reset signal when
V < V and releases the reset signal
DD LVD
 V
when V
DD LVD

DD
CHAPTER 19 VOLTAGE DETECTOR
) with the detection voltage (V
, V ) can be selected by using the option byte as
LVDH LVDL
Releases an internal reset by detecting
V
. release of the POR.
Generates an interrupt request signal by
detecting V
power on after the second release of the
POR.
, V , V ), and generates an
LVDH LVDL LVD
) is used for triggering
LVDL
) can be specified in
LVD
Interrupt Mode
(LVIMDS1, LVIMDS0 = 0, 1)
 V
at power on after the first
DD LVD
 V
< V or V
DD LVD DD
) is
LVDH
at
LVD
626