JP2018107561A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start a CPU dedicated to radio communication without influencing other functions even when processing having a strict time constraint is being performed.SOLUTION: An imaging device includes: a first CPU controlling the operation of the imaging device; communication means performing radio communication; a second CPU dedicated to the communication means; and a nonvolatile memory storing data used in the first CPU and data used in the second CPU. If the second CPU is started when a predetermined function that is required to terminate processing within a set period is being executed, the second CPU loads data from the nonvolatile memory in a PIO mode. If the second CPU is started when the predetermined function is not executed, the second CPU loads data from the nonvolatile memory in a DMA mode.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an imaging apparatus.

  In recent years, imaging apparatuses such as digital cameras equipped with a CPU that exclusively controls wireless communication processing have appeared. The CPU dedicated to the wireless communication processing is configured to share the RAM with the main CPU that performs the entire processing of the digital camera. By performing wireless communication processing with this dedicated CPU for wireless communication processing, it is possible to perform wireless communication in parallel without affecting the camera's original functions such as shooting and recording, live view display, etc. Become.

  A CPU dedicated to wireless communication processing is activated when the wireless function is used. At this time, it is necessary to load the data necessary for starting up the CPU dedicated to the wireless communication processing from the ROM to the RAM. However, the loading of this data collides with the RAM access of the main CPU, which affects the processing of the digital camera. There is a case. In particular, when processing with severe time restrictions such as live view display or moving image recording processing is performed, the processing time does not fall within the regulation due to the collision of the RAM access, and there is a possibility that the display may become stuttered or the recording may be omitted.

  As a method of reducing the influence of collision with the RAM access of the main CPU, a part of the data to be loaded at the time of starting up the wireless communication dedicated CPU is loaded in advance to reduce the amount of data to be loaded at the time of starting up the wireless communication dedicated CPU. A method is conceivable. Japanese Patent Application Laid-Open No. 2004-133867 discloses a technique for DMA transfer at the time of starting only a program portion necessary for starting an initial screen in order to shorten the starting time.

JP 2006-285738 A

  However, even if the amount of data to be loaded when the CPU dedicated for wireless communication is started up, RAM access collision cannot be prevented as long as DMA transfer is used. Therefore, when processing with severe time constraints such as live view display is being performed, a method of limiting the wireless dedicated CPU data so as not to be DMA-transferred can be considered. In this case, if the data load itself is stopped, wireless activation cannot be performed during live view display, which leads to a decrease in usability.

  An object of the present invention is to provide an imaging apparatus capable of starting a wireless communication dedicated CPU without affecting other functions even during processing with severe time constraints such as live view display.

  A first CPU for controlling the operation of the imaging apparatus; a communication means for performing wireless communication; a dedicated second CPU for the communication means; data used by the first CPU; When the second CPU is activated during execution of a predetermined function that needs to finish processing within a certain period, the second CPU has a nonvolatile memory storing data used by the CPU. The CPU loads data from the non-volatile memory in the PIO mode, and when the second CPU is activated when the predetermined function is not executed, the second CPU reads from the non-volatile memory in the DMA mode. Load data.

  According to the present invention, the CPU dedicated to wireless communication can be activated without affecting other functions even during processing with severe time constraints such as live view display.

1 is a block diagram illustrating a configuration of a digital camera according to a first embodiment. The flowchart of the data load process of the radio | wireless exclusive CPU of 1st Embodiment. The flowchart of the data load process of radio | wireless exclusive CPU of 2nd Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. The embodiment described below is an example for realizing the present invention, and should be appropriately modified or changed according to the configuration and various conditions of the apparatus to which the present invention is applied. It is not limited to the embodiment. Moreover, you may comprise combining suitably one part of each embodiment mentioned later.

  Hereinafter, a case where the present invention is applied to a digital camera which is an imaging apparatus will be described as a first embodiment. In the present embodiment, live view display is assumed as processing with severe time constraints, but it can also be applied to processing such as moving image recording.

<Configuration of Digital Camera 100>
With reference to FIG. 1, an outline of a configuration and functions of a digital camera 100 according to an embodiment of the present invention will be described. The optical system 101 includes a zoom lens, a lens group including a focus lens, and a shutter having a diaphragm function. The imaging unit 102 is an imaging element configured with a CCD, a CMOS, or the like that converts a subject image into an electrical signal. The imaging unit 102 includes an A / D converter that converts an analog signal output from the imaging element into a digital signal.

  The main CPU 103 controls the operation of the entire apparatus by expanding and executing the program stored in the nonvolatile memory 108 in the work area of the volatile memory 107. A DMAC (Digital Memory Access Controller) 104 controls and executes data transfer from the nonvolatile memory 108 to the volatile memory 107 without the intervention of the main CPU 103. The main CPU 103 instructs the DMAC 104 about a transfer instruction, a transfer size, a transfer data address, a transfer direction, and the like, and the DMAC 104 executes data transfer according to this instruction.

  Similar to the main CPU 103, the communication dedicated CPU 105 develops and executes the program stored in the nonvolatile memory 108 in the work area of the volatile memory 107. The communication unit 112 is mainly controlled. The main CPU 103 and blocks 104 to 109 are connected to the bus 106. Bus 106 is used to transfer data and control signals between these blocks 103-109.

  The volatile memory 107 is a temporary storage device such as a random access memory (RAM), and stores still image data, moving image data (hereinafter, image data) output from the imaging unit 102, and the like. The volatile memory 107 stores various information such as file system information and management information in addition to image data, and further serves as a work memory for the main CPU 103. Further, the volatile memory 107 serves as a buffer memory at the time of image recording and reproduction. The work area of the main CPU 103 is not limited to the volatile memory 107, and may be an external hard disk or a memory card described later.

  The nonvolatile memory 108 is a secondary storage device such as a flash memory that can be electrically erased and recorded, such as a ROM (Read Only Memory). The nonvolatile memory 108 stores constants, programs, etc. for the operation of the main CPU 103. Here, the program is a program for executing various flowcharts to be described later. The nonvolatile memory 108 stores captured image files and connection history information such as wireless connection information described later.

  The recording medium 109 can record the image data output from the imaging unit 102. The recording medium 109 may be configured to be detachable from the digital camera 100 or may be built in the digital camera 100. That is, the digital camera 100 only needs to have a means for accessing at least the recording medium 109. In the recording medium 109, image data stored in the volatile memory 107 is recorded, or an already recorded image file and various information relating to camera control are read out.

  The operation unit 110 includes, for example, power on / off, moving image recording start / stop, still image shooting, zoom operation, operation mode switching described later, a switch for receiving a user operation through a GUI screen, a cursor key, a touch panel, and the like. It is. The display unit 111 performs display of a viewfinder image at the time of shooting, display of a shot image, character display for interactive operation, and the like. The display unit 111 is a display device such as a liquid crystal display or an organic EL display. The display unit 111 may be configured to be integrated with the digital camera 100 or may be an external device connected to the digital camera 100.

  The communication unit 112 is an interface for connecting to an external device. The digital camera 100 of this embodiment can exchange data with an external device via the communication unit 112. For example, image data generated by the imaging unit 102 can be transmitted to an external device via the communication unit 112.

  In the present embodiment, the communication unit 112 includes an interface for communicating with an external apparatus via a so-called wireless LAN in accordance with the IEEE 802.11 standard. The dedicated wireless CPU 105 controls the communication unit 112 to realize wireless communication with an external device. Note that the communication method is not limited to the wireless LAN, and includes, for example, an infrared communication method. The digital camera 100 only needs to have a means for accessing the communication unit 112, and does not necessarily have a communication unit. Further, a communication unit may be added to the digital camera 100 as an external accessory to communicate with an external device.

  In addition, by operating the communication unit 112 in an access point (hereinafter referred to as AP) mode, the digital camera 100 in the present embodiment is a kind of AP, but a simple AP (hereinafter simply referred to as a simple AP) with more limited functions. It is also possible to operate as AP). When the digital camera 100 operates as a simple AP, the digital camera 100 forms a network by itself. Devices around the digital camera 100 can recognize the digital camera 100 as an AP device and participate in a network formed by the digital camera 100. It is assumed that a program for operating the digital camera 100 is held in the nonvolatile memory 108 as described above.

  Note that although the digital camera 100 in this embodiment is a kind of AP, it is a simple AP that does not have a gateway function for transferring data received from a client device to an Internet provider or the like. Therefore, even if data is received from another device participating in the network formed by the own device, it cannot be transferred to a network such as the Internet.

  The close proximity wireless communication unit 113 includes, for example, an antenna for wireless communication and a modulation / demodulation circuit and a communication controller for processing a wireless signal. The proximity wireless communication unit 113 outputs a modulated wireless signal from an antenna, and demodulates the wireless signal received by the antenna, thereby non-contact proximity communication in accordance with ISO / IEC 18092 standard (so-called NFC: Near Field Communication). To realize. The close proximity wireless transfer unit 113 of the present embodiment is disposed on the side of the digital camera 100.

  Similar to the digital camera 100, when connecting to an external device having a close proximity wireless communication unit, communication is started by bringing the close proximity wireless communication units close to each other. In addition, when connecting using a close proximity wireless communication part, it is not necessary to contact close proximity wireless communication parts. Since the close proximity wireless communication unit can communicate even if they are separated from each other by a certain distance, in order to connect the devices to each other, it is only necessary to approach the range where close proximity wireless communication is possible. In the following description, it is also referred to as bringing close to the range where close proximity wireless communication is possible.

  Further, the close proximity wireless communication unit 113 outputs a modulated wireless signal from the antenna, and demodulates the wireless signal received by the antenna, thereby short-range wireless according to the IEEE 802.15 standard (so-called Bluetooth (registered trademark)). You may implement | achieve by communication. In this embodiment, Bluetooth (registered trademark) communication employs Bluetooth (registered trademark) Low Energy version 4.0, which has low power consumption. This Bluetooth (registered trademark) communication has a narrower communicable range than wireless LAN communication (that is, a communicable distance is short). In addition, Bluetooth (registered trademark) communication has a lower communication speed than wireless LAN communication. On the other hand, Bluetooth (registered trademark) communication consumes less power than wireless LAN communication.

<Start-up process of wireless CUP of digital camera 100>
Processing of the digital camera 100 will be described. In the present embodiment, processing up to completion of activation of the wireless CPU will be described as an example.

  Hereinafter, processing of the digital camera 100 that realizes the above-described operation will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the digital camera 100 in the present embodiment. 2 is performed immediately before the wireless function is executed. The execution of the wireless function may be triggered by the selection of the wireless function by the operation unit 110 of the digital camera 100. Alternatively, communication from the outside by proximity wireless communication performed via the proximity communication unit 113 may be used as a trigger, or a certain state of the digital camera may be used as a trigger.

  In step 201 (201 in FIG. 2), it is confirmed whether or not the digital camera is performing processing with severe time constraints. In this embodiment, it is confirmed whether or not live view display is being performed. If the live view is not displayed, the process proceeds to step 202. If the live view is being displayed, the process proceeds to step 205.

  In step 202, the data loading method of the wireless CPU 105 is set to DMA. The main CPU 103 instructs the DMAC 104 to transfer data, a transfer data address, and a transfer direction so as to load data from the nonvolatile memory 108 to the volatile memory 107.

  In step 203, the DMAC 104 that receives a transfer start instruction from the main CPU 103 executes data loading. When the DMA is completed, the DMAC 104 notifies the main CPU 103 of the transfer completion by a callback or the like. In step 204, the main CPU 103 confirms the end of DMA. If the DMA has not ended, the data transfer is continued in step 203. When the transfer is completed, the process proceeds to step 207.

  In step 205, the data loading method of the wireless dedicated CPU is set to PIO. In step 206, data is transferred in the PIO mode. The main CPU 103 copies data from the nonvolatile memory 108 to the volatile memory 107. This process is executed with a lower priority than the live view display process so as not to affect the RAM access of the live view display process. When the data transfer is completed, the process proceeds to step 207.

  Finally, in step 207, the wireless CPU is activated by the activation command of the main CPU 103.

<About data to load>
By preloading a part of the data to be loaded when the wireless communication dedicated CPU is activated and reducing the amount of data loaded when the wireless communication dedicated CPU is activated, the influence of the collision with the RAM access of the camera can be reduced. The advance includes, for example, a startup process after turning on the power of the digital camera.

  The data to be loaded in advance is preferably data that does not change by processing, such as algorithm or fixed value. These data are not changed by processing, and once loaded, they can be used any number of times. On the other hand, data that changes due to processing such as variables must be loaded and initialized each time processing is started. In this embodiment, a variable for handling parameters related to wireless communication corresponds to this, and is reloaded every time wireless communication is used.

  In the present embodiment, live view display has been described as an example of processing with strict time restrictions. However, the present invention can also be applied to processes with strict time restrictions such as moving image recording.

  Due to the effect of this embodiment, the user can use the dedicated wireless communication process without affecting the time-critical processing such as live view display even during the processing with severe time constraint such as live view display. The CPU can be activated.

  In the first embodiment, before starting the CPU dedicated to wireless communication processing, it is determined whether or not processing with severe time restrictions is being performed, and a data transfer method necessary for starting the CPU dedicated to wireless communication processing is determined. Explained how to change.

  In the second embodiment, a case will be described in which processing with severe time restrictions is started and ended while data necessary for starting a CPU dedicated to wireless communication processing is being transferred. Even when the live view display is started during DMA transfer of data necessary for starting up the CPU dedicated to wireless communication processing, it collides with the RAM access of the main CPU as in the first embodiment, and the digital The processing of the camera will be affected. For this reason, when live view display is started during DMA transfer of data necessary for starting a CPU dedicated to wireless communication processing, it is necessary to stop DMA transfer and switch to PIO transfer. In addition, even if the live view display is terminated during the PIO transfer of data necessary for starting up the CPU dedicated to wireless communication processing, the data transfer time can be reduced by changing the transfer from PIO to DMA. Reduction is possible.

  Hereinafter, a digital camera according to the second embodiment will be described. In the present embodiment, live view display is assumed as processing with severe time constraints, but it can also be applied to processing such as moving image recording.

<Configuration of Digital Camera 100>
The configuration of the digital camera in the present embodiment is the same as that in the first embodiment.

<Start-up process of wireless CUP of digital camera 100>
Processing of the digital camera 100 will be described. In the present embodiment, processing up to completion of activation of the wireless CPU will be described as an example.

  Hereinafter, processing of the digital camera 100 that realizes the above-described operation will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the digital camera 100 in the present embodiment. Note that the processing of FIG. 3 is performed immediately before the wireless function is executed. The execution of the wireless function may be triggered by the selection of the wireless function by the operation unit 110 of the digital camera 100. Alternatively, communication from the outside by proximity wireless communication performed via the proximity communication unit 113 may be used as a trigger, or a certain state of the digital camera may be used as a trigger.

  In step 301 (301 in FIG. 3), it is confirmed whether or not the digital camera is performing processing with severe time constraints. In this embodiment, it is confirmed whether or not live view display is being performed. If the live view is not displayed, the process proceeds to step 302. If the live view is being displayed, the process proceeds to step 308.

  In step 302, the data loading method of the wireless dedicated CPU is set to DMA. The main CPU 103 instructs the DMAC 104 to transfer data, a transfer data address, and a transfer direction so as to load data from the nonvolatile memory 108 to the volatile memory 107. In step 303, the DMAC 104 that has received a transfer start instruction from the main CPU 103 executes data loading. When the DMA is completed, the DMAC 104 notifies the main CPU 103 of the transfer completion by a callback or the like.

  In step 304, it is confirmed whether or not the state of processing with severe time restrictions has changed (started or ended) during data transfer. If not, the process proceeds to step 305. If it has changed, go to Step 306. In step 305, the main CPU 103 confirms the end of DMA. If the DMA has not ended, the data transfer is continued in step 303. If the transfer is complete, the process proceeds to step 314.

  In step 306, the DMA transfer is stopped. The main CPU 103 instructs the DMAC 104 to stop DMA transfer. The DMAC 104 notifies the main CPU 103 of DMA transfer stop completion notification and the transferred data size.

  In step 307, the transfer management information is updated based on the transferred data size acquired in step 306. The transfer management information is information including the entire data size necessary for starting up the CPU dedicated to wireless communication processing, the transferred data size, and the like. By referring to this information, even when the data transfer is stopped halfway, the transfer can be resumed from the subsequent data. When step 307 ends, the process returns to step 301 again to determine whether or not the live view is being displayed, and the data loading method is changed in steps 302 and 303 depending on the state. Here, the transfer management information is referred to, the data transfer start position necessary for starting the CPU dedicated to wireless communication processing is designated, and the transfer is resumed from the next.

  In step 308, the data loading method of the wireless dedicated CPU is set to PIO. In step 309, data is transferred in the PIO mode. The main CPU 103 copies data from the nonvolatile memory 108 to the volatile memory 107. This process is executed with a lower priority than the live view display process so as not to affect the RAM access of the live view display process.

  In step 310, as in step 304, a change in the state of the live view display process is confirmed. If it has changed, go to Step 312. In step 311, it is determined whether the PIO transfer has been completed. If not completed, the transfer is continued in step 309. If completed, go to step 314.

  In step 312, the main CPU 103 stops the PIO transfer. In step 313, the transfer management information is updated in the same manner as in step 307, and the process returns to step 301 again to continue the processing as described above. Finally, in step 314, the wireless CPU is activated by the activation command of the main CPU 103.

  In the present embodiment, live view display has been described as an example of processing with strict time restrictions. However, the present invention can also be applied to processes with strict time restrictions such as moving image recording.

  Due to the effect of the present embodiment, the user affects processing with severe time constraints such as live view display even while data necessary for starting a CPU dedicated to wireless communication processing is being loaded. Therefore, processing with severe time constraints such as live view display can be executed.

100 Digital Camera 101 Optical System 102 Imaging Unit 103 Main CPU
104 DMAC (Digital Memory Access Controller)
105 CPU dedicated to communication
106 Bus 107 Volatile Memory 108 Nonvolatile Memory 109 Recording Medium 110 Operation Unit 111 Display Unit 112 Communication Unit 113 Proximity Wireless Communication Unit

Claims (3)

An imaging device,
A first CPU for controlling the operation of the imaging device;
A communication means for performing wireless communication;
A second CPU dedicated for the communication means;
A non-volatile memory storing data used in the first CPU and data used in the second CPU;
When the second CPU is activated during execution of a predetermined function that needs to finish processing within a certain period, the second CPU loads data from the nonvolatile memory in the PIO mode, and the predetermined function When the second CPU is activated when the second CPU is not executed, the second CPU loads data from the nonvolatile memory in the DMA mode. The nonvolatile memory includes, as data used by the second CPU, first data that handles algorithms and fixed values, and second data that handles variables,
The second CPU loads the first data from the non-volatile memory when the image pickup apparatus is activated, and loads the second data from the non-volatile memory immediately before the second CPU is activated. The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized.   When the second CPU is loaded with data from the nonvolatile memory in the DMA mode and changes to a state in which the predetermined function is executed, the second CPU reads data from the nonvolatile memory. The imaging apparatus according to claim 1, wherein after loading is stopped and the DMA mode is switched to the PIO mode, loading of data from the nonvolatile memory is resumed in the PIO mode.