Abstract: Aspects of the disclosure provide methods and apparatuses for generating an internal reset signal that is synchronous to a clock signal. In some embodiments, an apparatus includes a clock switch circuit and a plurality of serially coupled D flip-flops (DFFs). The clock switch circuit receiving the clock signal can output the clock signal in an on state and block the clock signal in an off state. The plurality of serially coupled DFFs are coupled to the clock switch circuit and driven by the clock signal. If an external reset signal is enabled, the plurality of serially coupled DFFs can enable the internal reset signal. If the external reset signal is disabled, after a predefined number of clock signal cycles, the plurality of serially coupled DFFs can disable the internal reset signal.

Abstract: Aspects of the disclosure provide methods and apparatuses for generating an internal reset signal that is synchronous to a clock signal. In some embodiments, an apparatus includes a clock switch circuit and a plurality of serially coupled D flip-flops (DFFs). The clock switch circuit receiving the clock signal can output the clock signal in an on state and block the clock signal in an off state. The plurality of serially coupled DFFs are coupled to the clock switch circuit and driven by the clock signal. If an external reset signal is enabled, the plurality of serially coupled DFFs can enable the internal reset signal. If the external reset signal is disabled, after a predefined number of clock signal cycles, the plurality of serially coupled DFFs can disable the internal reset signal.

Abstract: A method for switching an operating system suitable for an electronic device is disclosed. The electronic device is capable of running a first operating system and a second operating system. The user interface of the first operating system is displayed at a display unit of the electronic device, including information of at least one application program of the second operating system. When the information of the application program on the user interface of the first operating system is selected, the electronic device wakes up the second operating system and switches to display the user interface of the second operating system to execute the application program. Moreover, an electronic device using this method is also disclosed.