STM8L152C8T6 Datasheet, PDF (17/134 Pages) STMicroelectronics – 8-bit ultralow power MCU, up to 64 KB Flash + 2 KB data EEPROM, RTC, LCD, timers, USARTs, I2C, SPIs, ADC, DAC, comparators

STM8L15xx8, STM8L15xR6
Functional overview
3.3.3
Voltage regulator
The high density and medium+ density STM8L15xx devices embed an internal voltage
regulator for generating the 1.8 V power supply for the core and peripherals.
This regulator has two different modes:
• Main voltage regulator mode (MVR) for Run, Wait for interrupt (WFI) and Wait for event
(WFE) modes.
• Low power voltage regulator mode (LPVR) for Halt, Active-halt, Low power run and
Low power wait modes.
When entering Halt or Active-halt modes, the system automatically switches from the MVR
to the LPVR in order to reduce current consumption.
3.4
Clock management
The clock controller distributes the system clock (SYSCLK) coming from different oscillators
to the core and the peripherals. It also manages clock gating for low power modes and
ensures clock robustness.
Features
• Clock prescaler: to get the best compromise between speed and current consumption
the clock frequency to the CPU and peripherals can be adjusted by a programmable
prescaler
• Safe clock switching: Clock sources can be changed safely on the fly in run mode
through a configuration register.
• Clock management: To reduce power consumption, the clock controller can stop the
clock to the core, individual peripherals or memory.
• System clock sources: 4 different clock sources can be used to drive the system
clock:
– 1-16 MHz High speed external crystal (HSE)
– 16 MHz High speed internal RC oscillator (HSI)
– 32.768 Low speed external crystal (LSE)
– 38 kHz Low speed internal RC (LSI)
• RTC and LCD clock sources: the above four sources can be chosen to clock the RTC
and the LCD, whatever the system clock.
• Startup clock: After reset, the microcontroller restarts by default with an internal
2 MHz clock (HSI/8). The prescaler ratio and clock source can be changed by the
application program as soon as the code execution starts.
• Clock security system (CSS): This feature can be enabled by software. If a HSE
clock failure occurs, the system clock is automatically switched to HSI.
• Configurable main clock output (CCO): This outputs an external clock for use by the
application.
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