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Arduino library to support STM32 Low Power.

• Arduino_Core_STM32 version >= 1.3.0
• STM32RTC

• void begin(): configure the Low Power

• void idle(uint32_t ms): enter in idle modeparam ms (optional): number of milliseconds before to exit the mode. The RTC is used in alarm mode to wakeup the chip in ms milliseconds.

• void sleep(uint32_t ms): enter in sleep modeparam ms (optional): number of milliseconds before to exit the mode. The RTC is used in alarm mode to wakeup the chip in ms milliseconds.

• void deepSleep(uint32_t ms): enter in deepSleep modeparam ms (optional): number of milliseconds before to exit the mode. The RTC is used in alarm mode to wakeup the chip in ms milliseconds.

• void shutdown(uint32_t ms): enter in shutdown modeparam ms (optional): number of milliseconds before to exit the mode. The RTC is used in alarm mode to wakeup the board in ms milliseconds.

• void attachInterruptWakeup(uint32_t pin, voidFuncPtrVoid callback, uint32_t mode, LP_Mode LowPowerMode): Enable GPIO pin in interrupt mode. If the pin is a wakeup pin, it is configured as wakeup source (see board documentation).param pin: pin number
  param callback: pointer to callback
  param mode: interrupt mode (HIGH, LOW, RISING, FALLING or CHANGE)param LowPowerMode: Low power mode which will be used (IDLE_MODE, SLEEP_MODE, DEEP_SLEEP_MODE or SHUTDOWN_MODE). In case of SHUTDOWN_MODE only, Wakeup pin capability is activated.

• void enableWakeupFrom(HardwareSerial *serial, voidFuncPtrVoid callback): enable a UART peripheral in low power mode. See board documentation for low power mode compatibility.
  param serial: pointer to a UART
  param callback: pointer to a callback to call when the board is waked up.

• void enableWakeupFrom(STM32RTC *rtc, voidFuncPtr callback, void * data)attach a callback to the RTC peripheral.
  param rtc: pointer to RTC. Could be NULL as RTC is a Singleton.
  param callback: pointer to a callback to call when the board is waked up.
  param callback: data: optional pointer to callback data parameters (default NULL).

• void enableWakeupFrom(TwoWire *wire, voidFuncPtrVoid callback):enable an I2C peripheral in low power mode. See board documentation for low power mode compatibility.Currently not available.
  param wire: pointer to I2C
  param callback: pointer to a callback to call when the board is waked up.

Begin() function must be called at least once beforeidle(),sleep(),deepSleep() orshutdown() functions.

attachInterruptWakeup() orenableWakeupFrom() functions should be called beforeidle(),sleep(),deepSleep() orshutdown() functions.

• Idle mode: low wake-up latency (µs range) (e.g. ARM WFI). Memories andvoltage supplies are retained. Minimal power saving mainly on the core itself.

• sleep mode: low wake-up latency (µs range) (e.g. ARM WFI), Memories andvoltage supplies are retained. Minimal power saving mainly on the core itself buthigher than idle mode.

• deep sleep mode: medium latency (ms range), clocks are gated to reduced. Memoriesand voltage supplies are retained. If supported, Peripherals wake-up is possible (UART, I2C ...).

• shutdown mode: high wake-up latency (possible hundereds of ms or secondtimeframe), voltage supplies are cut except always-on domain, memory contentare lost and system basically reboots.

You can find the source files at
https://github.com/stm32duino/STM32LowPower