Voltage regulator
The regulator has three operation modes: main (MR), low power (LPR) and power down.
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MR is used in the nominal regulation mode (Run)
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LPR is used in the Stop modes.
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Power down is used in Standby Mode: the regulator output is in high impedance: the
kernel circuitry is powered-down, inducing zero consumption (but the contents of the
registers and SRAM are lost)
This regulator is always enabled after reset. It is disabled in Standby Mode, providing high
impedance output.
Low-power modes
The STM32F103xx performance line supports three low-power modes to achieve the best
compromise between low power consumption, short startup time and available wakeup
sources:
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Sleep mode
In Sleep mode, only the CPU is stopped. All peripherals continue to operate and can
wake up the CPU when an interrupt/event occurs.
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Stop mode
Stop mode allows to achieve the lowest power consumption while retaining the content
of SRAM and registers. All clocks in the 1.8 V domain are stopped, the PLL, the HSI
and the HSE RC oscillators are disabled. The voltage regulator can also be put either in
normal or in low power mode.
The device can be woken up from Stop mode by any of the EXTI line. The EXTI line
source can be one of the 16 external lines, the PVD output, the RTC alarm or the USB
wakeup.
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Standby mode
The Standby mode allows to achieve the lowest power consumption. The internal
voltage regulator is switched off so that the entire 1.8 V domain is powered off. The
PLL, the HSI and the HSE RC oscillators are also switched off. After entering Standby
mode, SRAM and registers content are lost except for registers in the Backup domain
and Standby circuitry.
The device exits Standby mode when an external reset (NRST pin), a IWDG reset, a
rising edge on the WKUP pin, or an RTC alarm occurs.
Note:
The RTC, the IWDG, and the corresponding clock sources are not stopped by entering Stop
or Standby mode.
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