STM8L052R8 Functional overview
Doc ID 023133 Rev 2 11/55
3.1 Low power modes
The high density value line STM8L05xxx devices support five low power modes to achieve
the best compromise between low power consumption, short startup time and available
wakeup sources:
● Wait mode: The CPU clock is stopped, but selected peripherals keep running. An
internal or external interrupt, event or a Reset can be used to exit the microcontroller
from Wait mode (WFE or WFI mode).
● Low power run mode: The CPU and the selected peripherals are running. Execution
is done from RAM with a low speed oscillator (LSI or LSE). Flash memory and data
EEPROM are stopped and the voltage regulator is configured in ultra low power mode.
The microcontroller enters Low power run mode by software and can exit from this
mode by software or by a reset.
All interrupts must be masked. They cannot be used to exit the microcontroller from this
mode.
● Low power wait mode: This mode is entered when executing a Wait for event in Low
power run mode. It is similar to Low power run mode except that the CPU clock is
stopped. The wakeup from this mode is triggered by a Reset or by an internal or
external event (peripheral event generated by the timers, serial interfaces, DMA
controller (DMA1) and I/O ports). When the wakeup is triggered by an event, the
system goes back to Low power run mode.
All interrupts must be masked. They cannot be used to exit the microcontroller from this
mode.
● Active-halt mode: CPU and peripheral clocks are stopped, except RTC. The wakeup
can be triggered by RTC interrupts, external interrupts or reset.
● Halt mode: CPU and peripheral clocks are stopped, the device remains powered on.
The wakeup is triggered by an external interrupt or reset. A few peripherals have also a
wakeup from Halt capability. Switching off the internal reference voltage reduces power
consumption. Through software configuration it is also possible to wake up the device
without waiting for the internal reference voltage wakeup time to have a fast wakeup
time of 5 µs.
高密度值线STM8L05xxx设备支持五种低功耗模式,以在低功耗、短启动时间和可用唤醒源之间实现最
佳折衷:
● 等待模式:CPU时钟已停止,但选定的外围设备仍在运行。内部或外部中断、事件或重置可用于使微控制器退出等待模式(WFE或WFI模式)。
● 低功耗运行模式:CPU和选定的外围设备正在运行。使用低速振荡器(LSI或LSE)从RAM执行。闪存和数据EEPROM停止,电压调节器配置为超低功率模式。
微控制器通过软件进入低功率运行模式,并可以通过软件或重置退出该模式。
必须屏蔽所有中断。它们不能用于使微控制器退出此模式。
● 低功耗等待模式:在低功耗运行模式下执行等待事件时进入此模式。它类似于低功耗运行模式,只是CPU时钟停止。此模式的唤醒由复位或内部或外部事件
(定时器、串行接口、DMA控制器(DMA1)和I/O端口生成的外围事件)触发。当事件触发唤醒时,系统返回低功率运行模式。
必须屏蔽所有中断。它们不能用于使微控制器退出此模式。 3uA
● 主动暂停模式:CPU和外围时钟停止,RTC除外。唤醒可以由RTC中断、外部中断或重置触发。
● 暂停模式:CPU和外围时钟停止,设备保持通电状态。通过外部中断或重置触发唤醒。一些外围设备还具有从停止唤醒功能。关闭内部参考电压可降低功耗。
通过软件配置,也可以在不等待内部参考电压唤醒时间的情况下唤醒设备,使其具有5μs的快速唤醒时间。