Holtek BS83A04C Manual page 43

BS83A04C
4-Key Enhanced Touch I/O Flash MCU
• RSTC Register
Bit 7
Name RSTC7
R/W R/W
POR 0
Bit 7~0 RSTC7~RSTC0: Reset function control
01010101: No operation
10101010: No operation
Other values: Reset MCU
If these bits are changed due to adverse environmental conditions, the microcontroller
will be reset. The reset operation will be activated after a delay time, t
RSTF bit in the RSTFC register will be set to 1.
• RSTFC Register
Bit 7
Name —
R/W —
POR —
Bit 7~4 Unimplemented, read as "0"
Bit 3 RSTF: Reset control register software reset flag
0: Not occurred
1: Occurred
This bit is set to 1 by the RSTC control register software reset and cleared by the
application program. Note that this bit can only be cleared to 0 by the application
program.
Bit 2 LVRF: LVR function reset flag
Described elsewhere.
Bit 1 Unimplemented, read as "0"
Bit 0 WRF: WDT control register software reset flag
Described elsewhere.
Low Voltage Reset – LVR
The microcontroller contains a low voltage reset circuit in order to monitor the supply voltage of the
device and provides an MCU reset should the value fall below a certain predefined level.
The LVR function is always enabled in the FAST or SLOW mode with a specific LVR voltage V
which is fixed at 1.7V. If the supply voltage of the device drops to within a range of 0.9V~V
such as might occur when changing the battery in battery powered applications, the LVR will
automatically reset the device internally and the LVRF bit in the RSTFC register will also be set to
1. For a valid LVR signal, a low supply voltage, i.e., a voltage in the range between 0.9V~V
exist for a time greater than that specified by t
supply voltage state does not exceed this value, the LVR will ignore the low supply voltage and will
not perform a reset function. Note that the LVR function will be automatically disabled when the
device enters the SLEEP or IDLE mode.
Rev. 1.00
6 5 4
RSTC6 RSTC5 RSTC4
R/W R/W R/W
1 0 1
6 5 4
— — —
— — —
— — —
LVR
LVR
Internal Reset
Low Voltage Reset Timing Chart
43
3 2
RSTC3 RSTC2 RSTC1
R/W R/W R/W
0 1
3 2
RSTF LVRF
R/W R/W
0 x
in the LVR Electrical Characteristics. If the low
t + t
RSTD SST
1 0
RSTC0
R/W
0 1
and the
SRESET
1 0
— WRF
— R/W
— 0
"x": unknown
,
LVR
LVR
must
LVR
March 24, 2020