Rev. 1.20
146
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Rev. 1.20
147
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BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
LVD Operation
The Low Voltage Detector function operates by comparing the power supply voltage, V
DD
, with a
pre-specified voltage level stored in the LVDC register. This has a range of between 2.
7
V and 4.0V.
When the power supply voltage, V
DD
, falls below this pre-determined value, the LVDO bit will be
set high indicating a low power supply voltage condition. The Low Voltage Detector function is
supplied by a reference voltage which will be automatically enabled. When the device is in SLEEP
mode the low voltage detector will be automatically disabled even if the LVDEN bit is high. After
enabling the Low Voltage Detector, a time delay t
LVDS
should be allowed for the circuitry to stabilise
before reading the LVDO bit. Note also that as the V
DD
voltage may rise and fall rather slowly, at the
voltage nears that of V
LVD
, there may be multiple bit LVDO transitions.
LVD Operation
The Low Voltage Detector also has its own interrupt, providing an alternative means of low voltage
detection, in addition to polling the LVDO bit. The interrupt will only be generated after a delay
of t
LVD
after the LVDO bit has been set high by a low voltage condition. In this case, the LV
D
F
interrupt request flag will be set, causing an interrupt to be generated if V
DD
falls below the preset
LVD voltage. This will cause the device to wake-up from the SLEEP or IDLE Mode, however if the
Low Voltage Detector wake up function is not required then the LV
D
F flag should be first set high
before the device enters the SLEEP or IDLE Mode.
Содержание BS82B12A-3
Страница 33: ...Rev 1 20 33 January 23 2015 BS82B12A 3 BS82C16A 3 BS82D20A 3 Touch Key 8 Bit Flash MCU with LED LCD Driver ...
Страница 34: ...Rev 1 20 34 January 23 2015 BS82B12A 3 BS82C16A 3 BS82D20A 3 Touch Key 8 Bit Flash MCU with LED LCD Driver ...
Страница 35: ...Rev 1 20 35 January 23 2015 BS82B12A 3 BS82C16A 3 BS82D20A 3 Touch Key 8 Bit Flash MCU with LED LCD Driver ...