STM8L051F3P6 Datasheet, PDF (11/46 Pages) STMicroelectronics – Value line, 8-bit ultralow power MCU, 8-KB Flash

STM8L051F3
Functional overview
3.1
Low power modes
The low 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 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 RAM content is preserved. 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.
Doc ID 022985 Rev 1
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