STM32W108HB Datasheet, PDF (13/179 Pages) STMicroelectronics – High-performance, IEEE 802.15.4 wireless system-on-chip

STM32W108CB, STM32W108HB
Description
1.2.10
1.2.11
Note:
1.2.12
Voltage regulator
The regulator has three operation modes: main (MR), low power (LPR) and power down.
● MR is used in the nominal regulation mode (Run)
● LPR is used in the Stop mode
● 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 STM32W108 supports three low-power modes to achieve the best compromise
between low power consumption, short startup time and available wakeup sources:
● 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.
● Stop mode
Stop mode achieves 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 RC
and the HSE crystal 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 or the RTC alarm.
● Standby mode
The Standby mode is used 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 RC and the HSE crystal oscillators are also switched off. After entering
Standby mode, SRAM and register contents 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.
The RTC, the IWDG, and the corresponding clock sources are not stopped by entering Stop
or Standby mode.
DMA
The flexible 7-channel general-purpose DMA is able to manage memory-to-memory,
peripheral-to-memory and memory-to-peripheral transfers. The DMA controller supports
circular buffer management avoiding the generation of interrupts when the controller
reaches the end of the buffer.
Each channel is connected to dedicated hardware DMA requests, with support for software
trigger on each channel. Configuration is made by software and transfer sizes between
source and destination are independent.
The DMA can be used with the main peripherals: SPI, I2C, USART, general purpose timers
TIMx and ADC.
Doc ID 16252 Rev 2
13/179