Abstract:
An electronic device includes a motherboard that includes a south bridge, a universal serial bus (USB) 3.0 connector, and a ground module. The south bridge is connected to the USB3.0 connector for transporting USB3.0 signals and USB2.0 signals. The grounded module is connected to the south bridge and the USB3.0 connector. The south bridge is used for controlling the ground module to work. The USB2.0 signals transmit between the south bridge and the USB3.0 connector flow into the ground, while the ground module is working.

Description:
FIELD 
       [0001]    The subject matter herein generally relates to a motherboard. 
       BACKGROUND 
       [0002]    Traditional universal serial bus (USB) 3.0 interfaces are compatible with USB2.0 interfaces. That is to say USB3.0 interfaces are capable of transmitting USB3.0 signals and USB2.0 signals. When a motherboard is testing USB3.0 signals, the USB2.0 signals should be failed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
           [0004]      FIG. 1  is a block diagram of an embodiment of a motherboard. 
           [0005]      FIG. 2  is a diagrammatic view of the motherboard in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0006]    It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
         [0007]    Several definitions that apply throughout this disclosure will now be presented. 
         [0008]    The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “comprising” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. 
         [0009]    The present disclosure is described in relation to a motherboard. 
         [0010]      FIG. 1  illustrates an embodiment of a motherboard  100 . The motherboard  100  comprises a south bridge  10 , a universal serial bus (USB) 3.0 connector  20 , and a ground module  30 . The south bridge  10  is coupled to the USB3.0 connector  20  and the ground module  30 . The USB3.0 connector  20  is coupled to the ground module  30 . The south bridge  10  is capable of transmitting USB3.0 signals and USB2.0 signals to the USB3.0 connector  20 , and controlling the ground module  30  to operate. The ground module  30  is capable of transmitting the USB2.0 signals between the south bridge  10  and the USB3.0 connector  20  to the ground. 
         [0011]      FIG. 2  illustrates the schematic of the motherboard  100 . The south bridge  10  comprises a first sending pin TX 1  and a second sending pin TX 2  for sending USB3.0 signals, a first receiving pin RX 1  and a second receiving pin RX 2  for receiving USB3.0 signals, a first transmitting pin TR 1  and a second transmitting pin TR 2  for transmitting USB2.0 signals, and an output pin DP for outputting a control signal. 
         [0012]    The USB3.0 connector  20  comprises a third sending pin TX 3  and a forth sending pin TX 4  for sending USB3.0 signals, a third receiving pin RX 3  and a forth receiving pin RX 4  for receiving USB3.0 signals, and a third transmitting pin TR 3  and a forth transmitting pin TR 4  for transmitting USB2.0 signals. 
         [0013]    The first sending pin TX 1  is coupled to the third receiving pin RX 3  and the second sending pin TX 2  is coupled to the forth receiving pin RX 4 . The first receiving pin RX 1  is coupled to the third sending pin TX 3  and the second receiving pin RX 2  is coupled to the forth sending pin TX 4 . The first transmitting pin TR 1  is coupled to the third transmitting pin TR 3  and the second transmitting pin TR 2  is coupled to the forth transmitting pin TR 4 . 
         [0014]    The ground module  30  comprises a first electronic switch Q 1  and a second electronic switch Q 2 . First ends of the first electronic switch Q 1  and the second electronic switch Q 2  are coupled to the output pin DP for receiving the control signal. Second ends of the first electronic switch Q 1  and the second electronic switch Q 2  are grounded. A third end of the first electronic switch Q 1  is coupled to the third transmitting pin TR 3  and a third end of the second electronic switch Q 2  is coupled to the forth transmitting pin TR 4 . In at least one embodiment, the first electronic switch Q 1  and the second electronic switch Q 2  can be n-channel field-effect transistors (FETs). The first ends of the first electronic switch Q 1  and the second electronic switch Q 2  are corresponding to gates of the FETs. The second ends of the first electronic switch Q 1  and the second electronic switch Q 2  are corresponding to sources of the FETs. The third ends of the first electronic switch Q 1  and the second electronic switch Q 2  are corresponding to drains of the FETs. In other embodiments, the first electronic switch Q 1  and the second electronic switch Q 2  can be npn bipolar junction transistors or any switches having a same function. 
         [0015]    When the motherboard  100  is testing the USB3.0 signal, the output pin DP outputs a first control signal. The electronic switch Q 1  and the second electronic switch Q 2  are switched on after the first ends receive the first control signal. The third transmitting pin TR 3  is grounded through the first electronic switch Q 1  and the forth transmitting pin TR 4  is grounded through the second electronic switch Q 2 , so that the USB2.0 signals transmitted between the south bridge  10  and the USB3.0 connector  20  are grounded. Then, the motherboard  100  can be further tested. 
         [0016]    When the motherboard  100  is not testing the USB3.0 signal, the output pin DP outputs a second control signal. The electronic switch Q 1  and the second electronic switch Q 2  are switched off after the first ends receive the second control signal. The south bridge  10  and the USB3.0 connector  20  can send and receive USB2.0 signals through the first transmitting pin TR 1 , the second transmitting pin TR 2 , the third transmitting pin TR 3 , and the forth transmitting pin TR 4 . Then, USB2.0 signals and USB3.0 signals can be transmitted between the south bridge  10  and the USB3.0 connector  20 . In at least one embodiment, the first control signal can be a high level signal, and the second control signal can be a low level signal. 
         [0017]    As detailed above, the motherboard  100  has the south bridge  10  controlling the ground module  30  to operate, so that the USB2.0 signals transmitted between the south bridge  10  and the USB3.0 connector  20  are grounded. Then, the motherboard  100  can test the USB3.0 signal. 
         [0018]    The embodiments shown and described above are only examples. Many details are well known by those in the art therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the details, especially in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.