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Rev. 1.40
132
March 29, 2019
Rev. 1.40
133
March 29, 2019
HT45F23A/HT45F24A
TinyPower
TM
Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPower
TM
Flash MCU with OPA & Comparators
Buzzer Output Pin Control
Note: The above drawing shows the situation where both pins PA6 and PA7 are selected by BPCTL
option to be BZ and BZ buzzer pin outputs. The Port Control Register of both pins must have
already been setup as output. The data setup on pin PA7 has no effect on the buzzer outputs.
Low Voltage Detector – LVD
The devices have Low Voltage Detector function, also known as LVD. This enabled the devices to
monitor the power supply voltage, V
DD
, and provide a warning signal should it fall below a certain
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 detemined. A low voltage condition is indicated when the LVDO bit is
set. If the LVDO bit is low, this indicates that the V
DD
voltage is above the preset low voltage 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.