Standby Mode; Table 10. Stop Mode - ST STM32F102 Series Reference Manual

RM0008
When the voltage regulator operates in low-power mode, an additional startup delay is
incurred when waking up from Stop mode. By keeping the internal regulator ON during Stop
mode, the consumption is higher although the startup time is reduced.
Table 10.
Stop mode
Mode entry
Mode exit
Wakeup latency
4.3.5

Standby mode

The Standby mode allows to achieve the lowest power consumption. It is based on the
Cortex-M3 deepsleep mode, with the voltage regulator disabled. The 1.8 V domain is
consequently powered off. The PLL, the HSI oscillator and the HSE oscillator are also
switched off. SRAM and register contents are lost except for registers in the Backup domain
and Standby circuitry (see
Entering Standby mode
Refer to
In Standby mode, the following features can be selected by programming individual control
bits:
● Independent Watchdog (IWDG): the IWDG is started by writing to its Key register or by
hardware option. Once started it cannot be stopped except by a reset. See
Section 16.3
●
real-time clock (RTC): this is configured by the RTCEN bit in the Backup domain control
register (RCC_BDCR)
●
Internal RC oscillator (LSI RC): this is configured by the LSION bit in the Control/status
register (RCC_CSR).
●
External 32.768 kHz oscillator (LSE OSC): this is configured by the LSEON bit in the
Backup domain control register (RCC_BDCR)
Stop mode
WFI (Wait for Interrupt) or WFE (Wait for Event) while:
– Set SLEEPDEEP bit in Cortex™-M3 System Control register
– Clear PDDS bit in Power Control register (PWR_CR)
– Select the voltage regulator mode by configuring LPDS bit in PWR_CR
Note: To enter Stop mode, all EXTI Line pending bits (in
(EXTI_PR)) and RTC Alarm flag must be reset. Otherwise, the Stop mode
entry procedure is ignored and program execution continues.
If WFI was used for entry:
Any EXTI Line configured in Interrupt mode (the corresponding EXTI
Interrupt vector must be enabled in the NVIC). Refer to
table on page 123
If WFE was used for entry:
Any EXTI Line configured in event mode. Refer to
event management on page 127
HSI RC wakeup time + regulator wakeup time from Low-power mode
Figure
Table 11 for more details on how to enter Standby mode.
in Section 16: Independent watchdog
Description
4).
Power control (PWR)
Pending register
Table 36: Vector
Section 8.2.3: Wakeup
(IWDG).
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