Abstract: A stopping structure of a fan is described. An opening is opened on a surface of a frame, and a bearing support is disposed within the frame. A blade wheel is accommodated within the frame and pivoted to the bearing support. Then, a stopper is disposed at the frame corresponding to the opening, such that a distance between the stopper and the blade wheel is smaller than a distance between blades of the blade wheel and the frame. When the blade wheel moves outwards relative to the bearing support, the blade wheel is stopped by the stopper to prevent the blades from interfering with the frame, and a reactive force is generated at an axial center position of the blade wheel, so that an axle of the blade wheel is maintained on the same central axis as the bearing support when the axle restores an original position thereof.

Abstract: A debug device sharing a memory card slot with a card reader is disclosed in the invention, which utilizes a memory card slot of a card reader as an interface thereof. Users can insert an external debug card into the slot like using a memory card, and examine messages about Power On Self Test codes without removing the case of a computer. A debug circuit is electrically connected between a computer motherboard and an interface of the memory card slot, and the interface of the memory card slot a multiplexed interface shared between a card reader controller and the debug circuit.

Abstract: A clock switching circuit comprises a multiplexer, a gate, a first detector, a second detector and a state machine. The multiplexer receives two clock signals and outputs one of them through the gate. The first detector is coupled to the output of the multiplexer and the second detector is coupled to the output of the gate. The state machine controls the output of the gate and the multiplexer in response to signals from the first and second detector, and prevent glitches from being output by the gate.