Rev. 1.20
60
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Rev. 1.20
61
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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
Low Voltage Reset – LVR
The microcontroller contains a low voltage reset circuit in order to monitor the supply voltage of the
device. The LVR function is always enabled with a specific LVR voltage, V
LVR
. If the supply voltage
of the device drops to within a range of 0.9V~V
LVR
such as might occur when changing the battery,
the LVR will automatically reset the device internally and the LVRF bit in the CTRL register will
also be set high.
F
or a valid LVR signal, a low voltage, i.e., a voltage in the range between 0.9V~V
LVR
must exist for greater than the value t
LVR
specified in the A.C. characteristics. If the low voltage state
does not exceed this value, the LVR will ignore the low supply voltage and will not perform a reset
function. The actual V
LVR
is fixed at a voltage value of 2.55V. Note that the LVR function will be
automatically disabled when the device enters the SLEEP or IDLE mode.
Note: t
RSTD
is power-on delay, typical time=50ms
Low Voltage Reset Timing Chart
•
CTRL Register
Bit
7
6
5
4
3
2
1
0
Name
FSYSON
—
HIRCS1
HIRCS0
LXTLP
LVRF
D1
WRF
R/W
R/W
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
—
0
0
0
x
0
0
"x" �nknown
Bit 7
FSYSON
: f
SYS
Control in IDLE Mode
Describe elsewhere
Bit 6
Unimplemented, read as
"
0
".
Bit 5 ~ 4
HIRCS1~HIRCS0
: HIRC frequency clock select
Describe elsewhere
Bit
3
LXTLP
: LXT low power control
Describe elsewhere
Bit
2
LVRF
: LVR function reset flag
0: Not occur
1: Occurred
This bit is set high when a specific Low Voltage Reset situation condition occurs. This
bit can only be cleared to zero by the application program.
Bit 1
Undefined bit
This bit can be read or written by user software program
Bit 0
WRF
: WDT Control register software reset flag
Describe elsewhere
Watchdog Time-out Reset during Normal Operation
The Watchdog time-out Reset during normal operation is the same as a LVR reset except that the
Watchdog time-out flag TO will be set to "1".
Note: t
RSTD
is power-on delay, typical time=16.7ms
WDT Time-out Reset during Normal Operation Timing Chart
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 ...