Abstract:
A dual-processor system includes a power supply, a temporary memory, a non-volatile memory and two processors. The non-volatile memory stores an initialization program code, a first configuration file corresponding to a first operating system, and a second configuration file corresponding to a second operating system. Compared to the first operating system, the second operating system has a shorter interrupt latency and a shorter thread switching latency. After the power supply starts to supply power, the first processor executes the initialization program code to perform operations of initializing the temporary memory, loading the second configuration file into the temporary memory, notifying the second processor to fetch the second configuration file from the temporary buffer, loading the first configuration rile into the temporary memory and establishing the first operating system according to the first configuration file.

Description:
[0001]    This application claims the benefit of U.S. provisional application Ser. No. 62/313,153, filed Mar. 25, 2016, the subject matter of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates to an electronic system comprising dual processors. 
         [0004]    Description of the Related Art 
         [0005]    Under the consideration of convenience, an outdoor surveillance equipment is usually powered by a battery. Therefore, how to reduce power consumption to prolong the utilization time of a battery is one essential design goal. 
         [0006]    To prevent missing critical images, a surveillance system starts video capturing once a change arises in the ambient environment. To prevent a latency caused by a boot process, the surveillance system usually keeps staying in a standby state. However, being in the standby state over an extended period of time results in a large amount of power consumption and shortens the utilization time of the battery. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention is directed to a dual-processor system and a control method thereof to solve the above issues. 
         [0008]    A dual-processor system is provided according to an embodiment of the present invention. The dual-processor system includes a power supply, a temporary memory, a non-volatile memory, a first processor and a second processor. The non-volatile memory stores an initialization program code, a first configuration file corresponding to a first operating system, and a second configuration file corresponding to a second operating system. Compared to the first operating system, the second operating system has a shorter interrupt latency and a shorter thread switching latency. The first processor is predetermined to operate under the first operating system. The processor is predetermined to operate under the second operating system. After the power supply starts to supply power, the first processor loads the initialization program code from the temporarily memory and executes the initialization program code to sequentially perform operations of initializing the temporary memory, loading the second configuration file from the non-volatile memory into the temporarily memory, notifying the second processor to fetch the second configuration file from the temporary memory to establish the second operating system, loading the first configuration file from the non-volatile memory into the temporary memory and establishing the first operating system according to the first configuration file. 
         [0009]    A control method for a dual-processor system is further provided according to another embodiment of the present invention. The dual-processor system includes a power supply, a temporary memory, a non-volatile memory, a first processor and a second processor. The non-volatile memory stores a first configuration file corresponding to a first operating system, and a second configuration file corresponding to a second operating system. Compared to the first operating system, the second operating system has a shorter interrupt latency and a shorter thread switching latency. According to the control method, after the power supply starts to supply power, the first processor sequentially performs operations of initializing the temporary memory, loading the second configuration file from the non-volatile memory into the temporary memory, notifying the second processor to fetch the second configuration file from the temporary memory to establish the second operating system, loading the first configuration file from the non-volatile into the temporary memory, and establishing the first operating system according to the first configuration file. 
         [0010]    The above and other aspects of the invention will become better understood with regard to the following detailed description of the non-limiting embodiments. The following description is made with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a block diagram of a dual-processor system according to an embodiment of the present invention; 
           [0012]      FIG. 2  is an exemplary storage space configuration in a temporary memory; 
           [0013]      FIG. 3  is a flowchart of an initialization process according to an embodiment of the present invention; 
           [0014]      FIG. 4  is a block diagram of a dual-processor system according to another embodiment of the present invention; 
           [0015]      FIG. 5  is a block diagram of a dual-processor system according to another embodiment of the present invention; 
           [0016]      FIG. 6  is a block diagram of a dual-processor system according to another embodiment of the present invention; and 
           [0017]      FIG. 7  is a flowchart of an initialization process according to another embodiment of the present invention. 
       
    
    
       [0018]    It should be noted that, the drawings of the present invention include functional block diagrams of multiple functional modules related to one another. These drawings are not detailed circuit diagrams, and connection lines therein are for indicating signal flows only. The interactions between the functional elements/or processes are not necessarily achieved through direct electrical connections. Further, functions of the individual elements are not necessarily distributed as depicted in the drawings, and separate blocks are not necessarily implemented by separate electronic elements. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0019]      FIG. 1  shows a dual-processor system  100  according to an embodiment of the present invention. The dual-processor system  100  includes a power supply  11 , a temporary memory  12 , a non-volatile memory  13 , a first processor  14  and a second processor  15 . In a waiting period, i.e., when the dual-processor system  100  is not required to perform a task such as video capturing, the power supply  11  does not supply power to the first processor  14  and the second processor  15 . In practice, the power supply  11  may be, for example but not limited to, a battery. 
         [0020]    The scope of the present invention is not limited to a specific storage mechanism. The temporary memory  12  may be a static random access memory (SRAM) or a dynamic random access memory (DRAM), and the non-volatile memory  13  may be a read-only memory (ROM) or a flash memory. The present invention is not limited to the above examples. 
         [0021]      FIG. 2  shows an example of a memory storage configuration of the temporary memory  12 . A storage region  12 A is accessible to only the first processor  14 ; storage regions  12 B and  12 C are accessible to both of the first processor  14  and the second processor  15 . 
         [0022]    The non-volatile memory  13  stores an initialization program code, a first configuration file corresponding to a first operating system, and a second configuration file corresponding to a second operating system. More specifically, a configuration file includes a program code and associated data for a processor to accordingly establish an operating system. It should be noted that, implementation details of establishing an operating system according to a configuration file are generally known to one person skilled in the art, and shall be omitted herein. 
         [0023]    In the dual-processor system  100 , the first processor  14  is preset to operate under the first operating system, and the second processor  15  is preset to operate under the second operating system. Further, compared to the first operating system, the second operating system has a shorter interrupt latency and a shorter thread switching latency. For example but not limited to, the first operating system may be a Linux operating system, and the second operating system may be a real-time operating system (RTOS). 
         [0024]    In one embodiment, when the power supply  11  starts to supply power, the temporary memory  12 , the non-volatile memory  13 , the first processor  14  and the second processor  15  are powered. First, the first processor  14  may load the initialization program code from the non-volatile memory  13  into an internal memory (not shown), which may be an SRAM have a capacity for sufficiently storing the initialization program code. The first processor  14  then starts executing the initialization program code to perform an initialization process  300  shown in  FIG. 3 . 
         [0025]    Referring to  FIG. 3 , in step S 31 , the first processor  14  initializes the temporary memory  12  to cause the temporary memory  12  to be accessible to the first processor  14  and the second processor  15 . In step S 32 , the first processor  14  loads the second configuration file from the non-volatile  13  into the temporary memory  12 , e.g., storing the second configuration file into the storage region  12 B of the temporary memory  12 . In step S 33 , the first processor  14  notifies the second processor  15  to start establishing the second operating system. For example, the first processor  14  sets a register of the second processor  15  to trigger the second processor  15  to start establishing the second operating system according to the second configuration file stored in the storage region  12 B of the temporary memory  12 . In step S 34 , the first processor  14  loads the first configuration file from the non-volatile memory  13  into the temporary memory  12 , e.g., storing the first configuration file to the storage region  12 A. In step S 35 , the first processor  14  establishes the first operating system according to the first configuration file stored in the storage region  12 A. 
         [0026]    Known from the above description, the first processor  14  is prioritized to assist the second processor  15  to establish the second operating system before it starts establishing its first operating system. Compared to the first operating system (e.g., a Linux operating system), because the second operating system (e.g., an RTOS) has a shorter interrupt latency and a shorter thread switching latency, the second processor  15  can establish the second operating system before the first processor  14  completes establishing the first operating system. Thus, even the dual-processor system  100  does not keep staying in a standby state, once the power supply  11  starts to supply power, the second processor  15  in the dual-processor system  100  is capable of completing establishing the second operating system and starting performing a task. In one embodiment, the second processor  15  starts performing a task of capturing an external update, before the first processor completes establishing the first operating system. Thus, the dual-processor system  100  may be promptly activated to perform the task of video capturing to minimize the probability of missing critical images. Further, as the dual-processor system  100  may be promptly activated to perform the task of video capturing without being in a standby state over an extended period of time, power consumption is saved and a utilization time of a battery is prolonged. 
         [0027]    Referring to  FIG. 4 , the dual-processor system  100  may further include a capturing element  16  coupled to the second processor  15  and the temporary memory  12 . In one embodiment, after completing establishing the second operating system (e.g., an RTOS), the second processor  15  executes a driver of the capturing element  16 , so as to control the capturing element  16  to capture an external update and to store the external update to the storage region  12 C in the temporary memory  12 . For example, the external update may be a still image, a dynamic image or a sound, and the capturing element  16  may include a photographing device, a video recording device or a sound recording device. In one embodiment, before storing the external update to the temporary memory  12 , the second processor  15  may perform a compression process on the external update received from the capturing element  16 , and store the compressed external update to the storage region  12 C of the temporary memory  12 . 
         [0028]    Referring to  FIG. 5 , the dual-processor system  100  may further include a detection device  17  coupled to the power supply  11 . The detection device  17  detects an ambient environment condition, and requests the power supply  11  to start supplying power when the ambient environment condition satisfies a predetermined condition. For example, the detection device  17  may be realized by an infrared detector cooperating with a power control module (PMU), and the predetermined condition may be detecting a movement of an external object. When the infrared detector detects a movement of an external object, the infrared detector transmits a signal to the PMU to start supplying power to the components in the dual-processor system  100 , e.g., the temporary memory  12 , the first processor  14 , the second processor  15  and the capturing element  16 . 
         [0029]    Referring to  FIG. 6 , the dual-processor system  100  may further include a transmission device  18  coupled to the first processor  14 . In one embodiment, after completing establishing the first operating system (e.g., a Linux operating system), the first processor  14  may fetch the external update from the storage region  12 C of the temporary memory  12 , and request the transmission device  18  to send the external update to a remote storage system, a surveillance system or a mobile device. For example, the transmission device  18  may be a wireless transmission chip. 
         [0030]    In one embodiment, as shown in  FIG. 7 , the initialization process  300  may further include step S 36  between steps S 31  and S 32 . In step S 36 , the temporary memory  12 , the non-volatile memory  13 , the first processor  14  or the second processor  15  is set to operate at a rated speed i.e., a maximum speed). For example, the temporary memory  12 , the non-volatile memory  13 , the first processor  14  and the second processor  15  are all set to operate at a rated speed, and the dual-processor system  100  is allowed to more promptly start operating. 
         [0031]    In the above embodiments, the second processor  16  executes the driver of the capturing element  16  to control the capturing element  16  to capture the external update only after completing establishing the second operating system (e.g., an RTOS). However, the present invention is not limited to such example. For example, in another embodiment, without establishing any operating system, the second processor  15  may directly execute the driver of the capturing element  16  to control the capturing element  16  to capture the external update. 
         [0032]    A control method for a dual-processor system is further provided according to another embodiment of the present invention. The dual-processor system includes a power supply, a temporary memory, a non-volatile memory, a first processor and a second processor. The non-volatile memory stores a first configuration file corresponding to a first operating system, and a second configuration file corresponding to a second operating system. Compared to the first operating system, the second operating system has a shorter interrupt latency and a shorter thread switching latency. According to the control method, in a waiting period, the power supply does not supply power to the first processor and the second processor. After the power supply starts supplying power, the first processor sequentially performs the initialization process  300  in  FIG. 3 . One person skilled in the art can understand that, the operation variations in the description associated with the dual-processor system  100  are applicable to the control method of the dual-processor system, and shall be omitted herein. 
         [0033]    A non-transient computer-readable storage medium is provided according to another embodiment of the present invention. The non-transient computer-readable storage medium includes a program code executable by a dual-processor system. The dual-processor system includes a temporary memory, a first processor and a second processor. 
         [0034]    The program code includes an initialization program code, a first configuration file corresponding to a first operating system and a second configuration file corresponding to a second operating system. Compared to the first operating system, the second operating system has a shorter interrupt latency and a shorter thread switching latency. In practice, the non-transient computer-readable storage medium may be an electronic, magnetic or optical storage device, e.g., a ROM, a RAM, a CD-ROM, a DVD, a magnetic tape, a floppy disk or a hard drive. The program code may be realized by various program languages. It should be noted that, the operation variations of the dual-processor system  100  are applicable to the non-transient computer-readable storage medium, and shall be omitted herein. 
         [0035]    While the invention has been described by way of example and in terms of the embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.