Low Voltage Detector - Lvd; Lvd Register - Holtek HT67F2350 Manual

HT67F2350/HT67F2360
HT67F2370/HT67F2390
Advanced A/D Flash MCU with LCD & EEPROM
Low Voltage Detector – LVD
Each device has a Low Voltage Detector function, also known as LVD. This enabled the device to
monitor the power supply voltage, V
level. This function may be especially useful in battery applications where the supply voltage will
gradually reduce as the battery ages, as it allows an early warning battery low signal to be generated.
The Low Voltage Detector also has the capability of generating an interrupt signal.

LVD Register

The Low Voltage Detector function is controlled using a single register with the name LVDC. Three
bits in this register, VLVD2~VLVD0, are used to select one of eight fixed voltages below which
a low voltage condition will be determined. A low voltage condition is indicated when the LVDO
bit is set. If the LVDO bit is low, this indicates that the V
value. The LVDEN bit is used to control the overall on/off function of the low voltage detector.
Setting the bit high will enable the low voltage detector. Clearing the bit to zero will switch off the
internal low voltage detector circuits. As the low voltage detector will consume a certain amount of
power, it may be desirable to switch off the circuit when not in use, an important consideration in
power sensitive battery powered applications.
LVDC Register
Bit 7
Name —
R/W —
POR —
Bit 7~6 Unimplemented, read as "0"
Bit 5 LVDO: LVD output flag
0: No Low Voltage Detected
1: Low Voltage Detected
Bit 4 LVDEN: Low Voltage Detector Enable control
0: Disable
1: Enable
Bit 3 VBGEN: Bandgap Voltage Output Enable control
0: Disable
1: Enable
Note that the Bandgap circuit is enabled when the LVD or LVR function is enabled or
when the VBGEN bit is set to 1.
Bit 2~0 VLVD2~VLVD0: LVD Voltage selection
000: 2.0V
001: 2.2V
010: 2.4V
011: 2.7V
100: 3.0V
101: 3.3V
110: 3.6V
111: 4.0V
Rev. 1.60
, and provide a warning signal should it fall below a certain
DD
DD
6 5 4
— LVDO LVDEN VBGEN
— R R/W
— 0 0
245
voltage is above the preset low voltage
3 2 1
VLVD2 VLVD1
R/W R/W R/W
0 0 0
May 16, 2019
0
VLVD0
R/W
0