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/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Figure 4-3 PVD threshold waveform
Brown_out reset
(
BOR
)
BOR is a power-down reset controller built into the device, when the VDD voltage is lower than 1.62V (typ), the
device will remain in reset state.
Power modes
Overall MCU has 6 power modes: RUN,SLEEP,STOP0,STOP2,STANDBY and VBAT. Different mode has different
performance and power consumption. A summary of MCU power modes is shown below.
Table 4-1 Power modes
Mode
Condition
Enter
Exit
RUN
CPU boot
Peripheral configuration
Power on, system reset, low
power wake-up
Enter sleep, STOP0, STOP2,
standby and VBAT modes
SLEEP
CPU goes to sleep mode and the kernel
stops. With all peripherals configured, the
voltage regulator is still running. Any
interrupt and event can wake up the CPU
1
)
SCB_SCR.SLEEPDEEP =
0,
SCB_SCR.SLEEPONEXIT =
0,
WFI/WFE
2
)
SCB_SCR.SLEEPDEEP =
0, SCB_SCR.SLEEPONEXIT
= 1,
No interrupt waiting, CPU
returns from ISR
wake:
1) If entered via WFI or set
SCB_SCR.SLEEPONEXIT = 1,
any NVIC interrupt can exit
2) If entered via WFE or set
SCB_SCR.SEVONPEND=1, any
peripheral interrupt can exit;
SCB_SCR.SEVONPEND=0, the
external interrupt line exits
STOP0
[1]
CPU deep sleep mode:
WFI
/
WFE
:
wake:
VDD/VDDA
PVD threshold
PVD output
100mV
hysteresis