2 Replies Latest reply on Mar 24, 2013 11:06 PM by jasonrc

    Wake up of the power save mode.






           Is it possible to wake up the MCU by UART interrupt or other GPIO?


           Customer want to set the MCU to sleep mode and wake up the MCU by UART input.


           If it is possible, any codes have to be changed for this. The demo shows one timer to wake up the host. Is this the only way to wake up it?
        • 1. Re: Wake up of the power save mode.
          The STM32F20x has a WKUP pin on port A0.


          You could connect to this pin.


          WICED doesnt have a specific API to set this up yet.
          • 2. Re: Wake up of the power save mode.
            It sounds like you want to configure two wakeups sources when the STM32 is in STOP MODE.


            These sources are:



            1. Wake when a WLAN packet is received (this is configured by default via the WLAN out-of-band interrupt)

            3. Wake on UART activity



            I think the only way to wake from UART is to reconfigure the UART input pin(s) as a GPIO(s) before going to STOP MODE.


            Section 2.2.18 of the STM32F2xx Datasheet has info about wakeups from STOP MODE.



            I have copied the relevant info below.


            STM32 Stop mode


            The Stop mode achieves the lowest power consumption while retaining the contents of


            SRAM and registers. All clocks in the 1.2 V domain are stopped, the PLL, the HSI RC


            and the HSE crystal oscillatorsare disabled. The voltage regulator can also be put


            either in normal or in low-power mode.


            The device can be woken up from the Stop mode by any of the EXTI line. The EXTI line source can be one of the 16 external lines, the PVD output, the RTC alarm / wakeup /


            tamper / time stamp events, the USB OTG FS/HS wakeup or the Ethernet wakeup.