Rev. 1.10
76
October 23, 2020
Rev. 1.10
77
October 23, 2020
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
Bit 0
WRF
: WDT control register software reset flag
Refer to the Watchdog Timer Control Register section.
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 can be enabled or disabled by the LVRC control register. If the LVRC control register is
configured to enable the LVR function, the LVR function will be always enabled except in the SLEEP
or IDLE mode. 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 in battery powered applications, the LVR will automatically
reset the device internally and the LVRF bit in the RSTFC register will also be set high. For a valid
LVR signal, a low supply voltage, i.e., a voltage in the range between 0.9V~V
LVR
must exist for a time
greater than that specified by t
LVR
in the LVD/LVR Electrical characteristics. If the low supply 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
value can be selected by the LVS bits in the LVRC register. If the
LVS7~LVS0 bits are changed to some different values by environmental noise, the LVR will reset the
device after a delay time, t
SRESET
. When this happens, the LRF bit in the RSTFC register will be set
high. After power on the register will have the value of 01100110B. Note that the LVR function will
be automatically disabled when the device enters the IDLE or SLEEP mode.
LVR
Internal Reset
t
RSTD
+ t
SST
Low Voltage Reset Timing Chart
• LVRC Register
Bit
7
6
5
4
3
2
1
0
Name
LVS7
LVS6
LVS5
LVS4
LVS3
LVS2
LVS1
LVS0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
1
1
0
0
1
1
0
Bit 7~0
LVS7~LVS0
: LVR voltage selection
01100110: 1.7V
01010101: 1.9V
00110011: 2.55V
10011001: 3.15V
10101010: Reserved
11110000:
LVR disable
Any other value: Generates MCU reset – register is reset to POR value
When an actual low voltage condition occurs, as specified by one of the four defined
LVR voltage values above, an MCU reset will be generated. The reset operation
will be activated after the low voltage condition keeps more than a t
LVR
time. In this
situation the register contents will remain the same after such a reset occurs.
Any register value, other than the six defined LVR values above, will also result in the
generation of an MCU reset. The reset operation will be activated after a delay time,
t
SRESET
. However in this situation the register contents will be reset to the POR value.