Accessory device, image pickup device, image pickup system, and storage medium

Abstract

Disclosed are an accessory device, an image pickup device, an image pickup system, a communication device, a communication method, and a storage medium. An accessory device comprising an optical member and configured to be detachably attached to an image pickup device includes a communication unit. The communication unit is configured to communicate with the image pickup device using a first communication method, which is used by the image pickup device to notify the accessory device that the image pickup device is communicating with the accessory device, and a second communication method and a third communication method, which are used to communicate between the image pickup device and the accessory device that has received the notification. The time interval between two request signals requesting a standby state for communication between the image pickup device and the accessory device using the third communication method is longer than the time interval between two request signals requesting a standby state for communication between the image pickup device and the accessory device using the second communication method.

Description

Technical Field

[0001] An aspect of the present disclosure relates to an accessory device, an image pickup device, an image pickup system, a communication device, a communication method, and a storage medium. Background Art

[0002] In an interchangeable lens imaging system, the interchangeable lens drives the focus lens unit and the aperture stop according to control commands from an imaging device (also called a camera body or image pickup device). In this system, control commands are transmitted from the camera body to the interchangeable lens, and information (data) is transmitted from the interchangeable lens to the camera body via a communication channel. In moving image capture and live view display, the camera system is required to perform smooth interchangeable lens control synchronized with the image capture cycle. To perform such control, it is necessary to synchronize the image capture timing of the camera body with the control timing of the interchangeable lens. Therefore, the camera body needs to complete the acquisition of information required to control the interchangeable lens and the transmission of control commands to the interchangeable lens within the image capture cycle. In recent years, due to advances in image capture control, the amount of information obtained by the camera body from the interchangeable lens has increased, and due to the shortening of the image capture cycle (increase in frame rate), the amount of data to be transmitted per unit time has increased.

[0003] This system includes not only interchangeable lenses but also accessory devices, such as wide-angle or telephoto converters, that serve as intermediate adapters attached between the camera body and the interchangeable lenses. Therefore, communication via the communication channel between the camera body and the accessory device is "one-to-many" communication. Japanese Patent No. 6427287 discusses a system capable of performing "one-to-many" communication.

[0004] In the system discussed in Japanese Patent No. 6427287, when a large amount of data is transmitted from an accessory device to the camera body, the camera body performs a process for receiving the large amount of data. In this case, the camera body repeats the data request process and the data reception process after issuing a data request by dividing the data by the size that can be received in a single reception process. Consequently, communication may take a long time. Furthermore, the completion of processes other than the communication process may be delayed. Summary of the Invention

[0005] One aspect of the present disclosure provides an accessory device that is useful, for example, for efficient data communication.

[0006] An accessory device includes an optical member and is configured to be detachably attached to an image pickup device, the accessory device including a communication unit configured to communicate with the image pickup device using a first communication unit for the image pickup device to notify the accessory device that the image pickup device is communicating with the accessory device, and a second communication unit and a third communication unit for communicating between the image pickup device and the accessory device that has received the notification. A time interval between two request signals requesting a standby state for communication between the image pickup device and the accessory device using the third communication unit is longer than a time interval between two request signals requesting a standby state for communication between the image pickup device and the accessory device using the second communication unit.

[0007] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a block diagram illustrating a configuration example of an imaging system.

[0009] Figure 2 is a block diagram illustrating a configuration example of a communication circuit in an imaging system.

[0010] Figure 3 This is a diagram illustrating the format of communication data.

[0011] Figure 4 This is a diagram illustrating a signal waveform in broadcast communication.

[0012] Figure 5 is a diagram illustrating a single waveform in peer-to-peer (P2P) communication.

[0013] Figure 6 3 is a diagram illustrating a signal waveform obtained when the communication method is switched.

[0014] Figure 7 This is a diagram illustrating a process flow executed by a communication master device in broadcast communication.

[0015] Figure 8 This is a diagram illustrating a flow of processing performed by a communication sub-device in broadcast communication.

[0016] Figure 9 This is a diagram illustrating a processing flow of a communication master device in P2P communication.

[0017] Figure 10A and Figure 10B This is a diagram illustrating a process flow executed by a communication sub-device in P2P communication.

[0018] Figure 11This is a diagram illustrating a signal waveform in P2P burst communication (communication child device transmission).

[0019] Figure 12 This is a diagram illustrating a processing flow of the communication master device in P2P burst communication (communication slave device transmission).

[0020] Figure 13 This is a diagram illustrating a processing flow of a communication device in P2P burst communication (communication device transmission).

[0021] Figure 14 1 is a diagram illustrating a signal waveform in P2P burst communication (communication master transmission).

[0022] Figure 15 This is a diagram illustrating a process flow executed by the communication master in P2P burst communication (communication master transmission).

[0023] Figure 16 This is a diagram illustrating a process flow executed by a communication slave device in P2P burst communication (communication master device transmission).

[0024] Figure 17 This is a diagram illustrating a signal waveform in broadcast communication.

[0025] Figure 18 This is a diagram illustrating a signal waveform in P2P burst communication (communication child device transmission).

[0026] Figure 19 This is a diagram illustrating a process flow executed by the communication master device in P2P burst communication (communication slave device transmission).

[0027] Figure 20 This is a diagram illustrating a flow of processing executed by a communication sub-device in P2P burst communication (communication sub-device transmission).

[0028] Figure 21 1 is a diagram illustrating signal waveforms in burst communication using the first communication channel and the second communication channel.

[0029] Figure 22 1 is a diagram illustrating a signal waveform in burst communication using a single communication channel. DETAILED DESCRIPTION

[0030] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In all drawings for describing exemplary embodiments, as a general rule (unless otherwise specified), the same reference numerals are assigned to the same components, and redundant descriptions will be omitted.

[0031] <Imaging System>

[0032] Figure 1 This figure illustrates an example configuration of an imaging system (also referred to as an image pickup system) according to a first exemplary embodiment. The imaging system includes an imaging device 200 (camera body), an intermediate adapter 300 serving as an accessory device that is detachably attached to the camera body 200, and an interchangeable lens device 100 serving as an accessory device that is detachably attached to the intermediate adapter 300. The camera body 200 and accessory devices such as the interchangeable lens device 100 and the intermediate adapter 300 communicate with each other (e.g., transmitting control commands or internal information) using their respective communication units. Each communication unit supports multiple communication methods and, depending on the type of data to be transmitted or the purpose of communication, switches to the same communication method in synchronization with each other, enabling communication in the communication format most suitable for each situation. Figure 1 The configuration in which the intermediate adapter 300 is attached to the camera body 200 is illustrated, but the configuration is not limited thereto. The interchangeable lens apparatus 100 may be directly attached to the camera body 200 , or a plurality of intermediate adapters may be attached between the camera body 200 and the interchangeable lens apparatus 100 .

[0033] The interchangeable lens device 100 and the intermediate adapter 300 are mechanically and electrically connected via the bracket 400. In a similar manner, the intermediate adapter 300 and the camera body 200 are mechanically and electrically connected via the bracket 401. The interchangeable lens device 100 and the intermediate adapter 300 operate various actuators and a microcomputer described below using power supplied from the camera body 200 via power supply terminal units provided on the brackets 400 and 401. The interchangeable lens device 100, the intermediate adapter 300, and the camera body 200 communicate with each other via communication terminal units (hereinafter referred to as communication terminals) provided on the brackets 400 and 401. Figure 2 Description) communicate with each other.

[0034] The interchangeable lens device 100 includes an imaging optical system. The imaging optical system includes, in order from the object side (OBJ side) to the image side, a front lens unit 101 as optical components, a zoom lens unit (magnification variation lens unit) 102 that moves for zooming (magnification variation), and an aperture stop unit 114 for adjusting the amount of light. The imaging optical system also includes an image stabilization lens unit 103 that moves for image stabilization, and a focus lens unit 104 that moves for focusing.

[0035] The zoom lens unit 102 and the focus lens unit 104 are held by holding frames 105 and 106, respectively. Each holding frame 105 and 106 is guided by a guide member, configured to be movable in the optical axis direction, and driven by stepping motors 107 and 108. The stepping motors 107 and 108 move the holding frames 105 and 106, respectively, in synchronization with drive pulses. The image stabilization lens unit 103 reduces image blur caused by camera shake, such as hand shake, by moving in a direction having a component orthogonal to the optical axis of the imaging optical system, thereby stabilizing the image.

[0036] The microcomputer 111 (also referred to as the lens microcomputer) functions as a control unit (lens or accessory control unit) that controls the operation of each unit in the interchangeable lens device 100. The lens microcomputer 111 includes a communication unit 112 (lens or accessory communication unit) and receives control commands and transmission request commands from the camera body 200 via the communication unit 112. The communication unit 112 includes a first communication path and a second communication path, described below. The lens microcomputer 111 performs control corresponding to the control commands and transmits data corresponding to the transmission request commands to the camera body 200 via the communication unit 112. In response to commands related to zooming and focusing, the lens microcomputer 111 outputs drive signals to the zoom drive circuit 119 and the focus drive circuit 120, thereby driving the stepping motors 107 and 108. In this manner, zoom processing is performed by the zoom lens unit 102, and focusing processing (which may be autofocus (AF) processing) is performed by the focus lens unit 104.

[0037] The aperture stop unit 114 includes aperture blades 114a and 114b. For example, the state of the aperture blades 114a and 114b is detected by a Hall element 115, and the output of the Hall element 115 is input to the lens microcomputer 111 via an amplifier circuit 122 and an analog-to-digital (A / D) conversion circuit 123. Based on the input signal from the A / D conversion circuit 123, the lens microcomputer 111 outputs a drive signal to the aperture drive circuit 121, thereby driving the aperture actuator 113. In this way, the aperture stop unit 114 performs light amount adjustment processing.

[0038] The lens microcomputer 111 also outputs a drive signal to the image stabilization drive circuit 125 based on camera shake detected by a vibration sensor such as a vibration gyro (gyro) sensor provided in the interchangeable lens device 100, thereby driving the image stabilization actuator 126 (e.g., a voice coil motor). In this way, image stabilization processing is performed by the image stabilization lens unit 103.

[0039] The interchangeable lens device 100 further includes an operation ring 130 and an operation ring detection unit 131. The operation ring detection unit 131 may include, for example, two photointerrupters that output two-phase signals according to the rotation of the operation ring 130. The lens microcomputer 111 obtains the amount of operation of the operation ring 130 based on the output of the operation ring detection unit 131. The lens microcomputer 111 also notifies the camera microcomputer 205 (described below) of the amount of operation of the operation ring 130 via the communication unit 112.

[0040] The intermediate adapter 300 is, for example, an expander and includes a magnification-varying lens 301 (optical member) and a microcomputer 302 (also referred to as an adapter microcomputer). The adapter microcomputer 302 functions as a control unit (adapter or accessory control unit) that controls the operation of each unit in the intermediate adapter 300. The adapter microcomputer 302 includes a communication unit 303 (adapter or accessory communication unit) that functions as an accessory communication unit and receives control commands and transmission request commands from the camera body 200 via the communication unit 303. The communication unit 303 includes a first communication path and a second communication path, which are described below. The adapter microcomputer 302 performs control corresponding to the control commands and transmits data corresponding to the transmission request commands to the camera body 200 via the communication unit 303.

[0041] The camera body 200 includes an image sensor 201 (also referred to as an image pickup element), such as a charge-coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor; an A / D conversion circuit 202; a signal processing circuit 203; a recording unit 204; a microcomputer (referred to as a camera microcomputer) 205; and a display unit 206. The image sensor 201 captures (photoelectrically converts) an object image formed by the imaging optical system included in the interchangeable lens apparatus 100 and outputs an electrical signal (analog signal). The A / D conversion circuit 202 converts the analog signal into a digital signal. The signal processing circuit 203 generates a video signal by performing image processing on the digital signal. The signal processing circuit 203 also generates focus information (the focus state of the imaging optical system) regarding the contrast of the object image and exposure information regarding the brightness of the object image based on the video signal. The signal processing circuit 203 outputs the video signal to the display unit 206. The display unit 206 displays a live view image based on the video signal for checking composition or focus state.

[0042] The camera microcomputer 205 functions as a control unit (camera control unit) that controls each unit included in the camera body 200 based on input from operating members such as an image capture instruction switch or various setting switches. The camera microcomputer 205 also includes a communication unit 208 (camera communication unit) and transmits control commands to the lens microcomputer 111 via the communication unit 208. The communication unit 208 includes a first communication path and a second communication path, described below. The control commands may include commands related to the zoom operation of the zoom lens unit 102 based on the operation of the zoom switch. The control commands may also include commands related to the light amount adjustment operation of the aperture stop unit 114 based on brightness information. The control commands may also include commands related to the focus adjustment operation of the focus lens unit 104 based on contrast information. The camera microcomputer 205 also transmits a transmission request command for acquiring control information and status information of the interchangeable lens apparatus 100 and the intermediate adapter 300 to the lens microcomputer 111 and the adapter microcomputer 302 via the communication unit 208.

[0043] In the following, reference will be made to Figure 2 A communication circuit in an imaging system including the camera body 200 , the interchangeable lens apparatus 100 , and the intermediate adapter 300 is described. Figure 2 This figure illustrates an example configuration of a communication circuit in an imaging system. The camera microcomputer 205, lens microcomputer 111, and adapter microcomputer 302 communicate using signal lines connected via communication terminal units provided on the supports 400 and 401. The signal lines include a signal line CS (notification channel; first communication channel; first communication path) that transmits signals for flow control of communication and for notifying communication timing. The signal lines also include a signal line DATA (data communication channel; second communication channel; second communication path) that transmits data and is used for data communication.

[0044] The signal line CS is connected to the camera microcomputer 205, the lens microcomputer 111, and the adapter microcomputer 302, and each microcomputer can detect the signal level (voltage level) on the signal line. The signal line CS is pulled up and connected to the power supply in the camera body 200. The signal line CS can also be connected to GND (ground) via the grounding switch 1121 of the interchangeable lens system 100, the grounding switch 2081 of the camera body 200, and the grounding switch 3031 of the intermediate adapter 300. In other words, the signal line CS is connected to an open drain. With this configuration, the interchangeable lens system 100, the camera body 200, and the intermediate adapter 300 can each set the signal level of the signal line CS to Lo (low; first level) by turning on (connecting) each grounding switch. Conversely, the signal level of the signal line CS can be set to Hi (high; second level) by turning off (blocking) the corresponding connection switches of the interchangeable lens system 100, the camera body 200, and the intermediate adapter 300. The details of the control signal transmitted on the signal line CS and the processing procedure will be described below.

[0045] The signal line DATA can be a single bidirectional data transmission line that can be used while changing the direction of data transmission. The signal line DATA can be connected to the lens microcomputer 111 via the input-output changeover switch 1122 included in the interchangeable lens device 100. The signal line DATA can also be connected to the camera microcomputer 205 via the input-output changeover switch 2082 included in the camera body 200. The signal line DATA can also be connected to the adapter microcomputer 302 via the input-output changeover switch 3032 included in the intermediate adapter 300. Each microcomputer includes a data output unit (CMOS method) for transmitting data and a data input unit (CMOS method) for receiving data. Each microcomputer can select whether to connect the signal line DATA to the data output unit or the data input unit by operating the input-output changeover switch. With this configuration, the interchangeable lens device 100, the camera body 200, and the intermediate adapter 300 can perform data transmission by connecting the signal line DATA to the data output unit by operating the corresponding input-output changeover switch. On the other hand, the interchangeable lens device 100, the camera body 200 and the intermediate adapter 300 can perform data reception by operating the corresponding input-output conversion switch to connect the signal line DATA to the data input unit. The details of the operation process of the input-output conversion switch will be described below.

[0046] Figure 2While the configuration example of the communication circuit is shown in the figure, the configuration of the communication circuit is not limited thereto. For example, the signal line CS may be pulled down and connected to GND inside the camera body 200, and then connected to a power source (not shown) via ground switches 1121, 2081, and 3031. The signal line DATA may be constantly connected to the various data input units of the microcomputer, and the microcomputer may be selectively connected to the various data output units via a switch.

[0047] <Communication Data Format>

[0048] Will refer to Figure 3 The format of communication data to be exchanged between the camera microcomputer 205 , the lens microcomputer 111 , and the adapter microcomputer 302 is described. Figure 3 This is a diagram illustrating the format of communication data to be sent and received using the signal line DATA. This format is the same as the format used in the broadcast communication and point-to-point (P2P) communication described below. The format of the communication data is based on so-called asynchronous communication in which transmission and reception are performed at a predetermined communication bit rate. In the non-transmission state where data transmission is not performed, the signal level is maintained at Hi. In order to notify the data receiving side of the start of data transmission, the signal level is set to Lo within a 1-bit period (start bit ST). In the subsequent 8-bit period from the 2nd bit to the 9th bit, 1 byte of data is transmitted. As the most significant bit (MSB) first format, the bit array of the data starts with the most significant data D7, followed by data D6, data D5, etc., and ends with the least significant data D0. 1 bit of parity information PA (parity bit) is added to the subsequent 10th bit. Finally, in order to notify the receiving side of the end of data transmission, the signal level is set to Hi within a 1-bit period (stop bit SP). With the stop bit SP, the transmission cycle of one frame of data starting from the start bit ST ends. Figure 3 The format of the communication data is illustrated, but the format of the communication data is not limited thereto. For example, the bit array of the data may be in a least significant bit (LSB) first format. Alternatively, the data may have a length of 9 bits. Alternatively, the format of the communication data does not need to include parity information PA. Alternatively, the format of the communication data may be different from the format used in the broadcast communication and P2P communication described below.

[0049] <Broadcast Communication Method (First Communication Method)>

[0050] Will refer to Figure 4 Broadcast communication to be performed among the camera microcomputer 205 , the lens microcomputer 111 , and the adapter microcomputer 302 is described. Figure 4The broadcast communication method (first communication method) is a communication method that simultaneously transmits data from one microcomputer among the camera microcomputer 205, the lens microcomputer 111, and the adapter microcomputer 302 to multiple other microcomputers (performs one-to-many simultaneous delivery). Figure 4 A case is illustrated in which, in response to the broadcast communication from the camera microcomputer 205 to the lens microcomputer 111 and the adapter microcomputer 302 , the broadcast communication is performed from the adapter microcomputer 302 to the camera microcomputer 205 and the lens microcomputer 111 .

[0051] First, the camera microcomputer 205, serving as the communication master, begins outputting a Lo signal (outputting a Lo-level signal) to the signal line CS to notify the lens microcomputer 111 and the adapter microcomputer 302, serving as the communication slaves, that broadcast communication will begin. The camera microcomputer 205 then outputs the data to be transmitted to the signal line DATA. In contrast, when the lens microcomputer 111 and the adapter microcomputer 302 detect the start bit ST input from the signal line DATA, they begin outputting a Lo signal to the signal line CS. At this point, the camera microcomputer 205 has already begun outputting a Lo signal to the signal line CS. Therefore, the signal level of the signal line CS does not change.

[0052] After the camera microcomputer 205 finishes outputting data up to the stop bit SP, it cancels the Lo output to the signal line CS. That is, the camera microcomputer 205 switches its output to Hi output (output of a Hi-level signal) to the signal line CS. In contrast, after the lens microcomputer 111 and the adapter microcomputer 302 finish receiving data up to the stop bit SP input from the signal line DATA, they analyze the received data and perform internal processing associated with the received data. Thereafter, the lens microcomputer 111 and the adapter microcomputer 302 make arrangements for receiving the next data and then cancel the Lo output to the signal line CS. As described above, by all of the camera microcomputer 205, the lens microcomputer 111, and the adapter microcomputer 302 canceling the Lo output to the signal line CS, the signal level of the signal line CS is set to Hi. Therefore, by checking that the signal level of the signal line CS is set to Hi, it can be determined that all microcomputers have completed processing related to the current communication and are making arrangements for the next communication.

[0053] After the adapter microcomputer 302 confirms that the signal level of the signal line CS has returned to Hi, the adapter microcomputer 302 starts to output Lo to the signal line CS to notify the camera microcomputer 205 and the lens microcomputer 111 that broadcast communication will start. Then, the adapter microcomputer 302 outputs the data to be sent to the signal line DATA. In contrast, when the camera microcomputer 205 and the lens microcomputer 111 detect the start bit ST input from the signal line DATA, the camera microcomputer 205 and the lens microcomputer 111 start to output Lo to the signal line CS. At this time, the adapter microcomputer 302 has already started to output Lo to the signal line CS. Therefore, the signal level of the signal line CS does not change.

[0054] After the adapter microcomputer 302 finishes outputting the data until the stop bit SP, the camera microcomputer 205 cancels the output of Lo to the signal line CS. In contrast, after the camera microcomputer 205 and the lens microcomputer 111 finish receiving the data until the stop bit SP that has been input from the signal line DATA, the camera microcomputer 205 and the lens microcomputer 111 perform analysis of the received data and internal processing associated with the received data. After that, the camera microcomputer 205 and the lens microcomputer 111 make arrangements to receive the next data, and then cancel the output of Lo to the signal line CS.

[0055] As described above, the signal to be transmitted via the signal line CS in the broadcast communication is used as a control signal indicating that the broadcast communication and the internal processing related to the communication are being performed.

[0056] Figure 4 The signal waveforms in the broadcast communication are exemplified, but the signal waveforms are not limited thereto. For example, the amount of data to be sent in one broadcast communication can be set to two or three bytes instead of one byte. In addition, the broadcast communication can be limited to one-way communication from the camera microcomputer 205 serving as the communication master device to the lens microcomputer 111 and the adapter microcomputer 302 serving as the communication slave devices.

[0057] <P2P Communication Method (Second Communication Method)>

[0058] Reference will be made to Figure 5 Describe the P2P communication to be performed among the camera microcomputer 205, the lens microcomputer 111, and the adapter microcomputer 302. Figure 5 is a diagram exemplifying the signal waveforms in the P2P communication. The second communication method is a communication method in which data transmission and reception (two-way communication) (performing one-to-one individual communication) are performed between the camera microcomputer 205 and only one microcomputer specified by the camera microcomputer 205 among the lens microcomputer 111 and the adapter microcomputer 302. Figure 5 The case where the lens microcomputer 111 is designated as a communication partner by the camera microcomputer 205 is illustrated. Figure 5 Also illustrated is a case where 2-byte data transmission is performed from the lens microcomputer 111 to the camera microcomputer 205 in response to 1-byte data transmission from the camera microcomputer 205 to the lens microcomputer 111. A procedure of specifying or switching a communication counterpart will be described below.

[0059] First, the camera microcomputer 205, acting as the communication master, outputs the data to be transmitted to the signal line DATA. After the camera microcomputer 205 finishes outputting data up to the stop bit SP, it starts outputting the Lo signal to the signal line CS. Thereafter, the camera microcomputer 205 prepares for reception of the next data and cancels the Lo signal to the signal line CS. After the lens microcomputer 111 detects the Lo signal input from the signal line CS, it analyzes the data received from the signal line DATA and performs internal processing associated with the received data. After the lens microcomputer 111 confirms that the signal level of the signal line CS has returned to Hi, it outputs the data to be transmitted as two consecutive bytes to the signal line DATA. After the lens microcomputer 111 finishes outputting data up to the stop bit SP of the second byte, it starts outputting the Lo signal to the signal line CS. Thereafter, the lens microcomputer 111 prepares for reception of the next data and cancels the Lo signal to the signal line CS. The adapter microcomputer 302 which is not specified as a communication partner in the P2P communication does not perform an operation on the signal line CS and the signal line DATA.

[0060] As described above, the signal to be transmitted via the signal line CS in the P2P communication serves as a control signal that instructs the end of transmission on the transmission side and a standby request for the next data transmission. Figure 5 The signal waveform in P2P communication is exemplified, but the signal waveform is not limited thereto. For example, the amount of data to be transmitted in one P2P communication may be 1 byte or 3 bytes or more, instead of 2 bytes.

[0061] <Switching the Communication Method>

[0062] Will refer to Figure 6 Switching between broadcast communication and P2P communication performed among the camera microcomputer 205 , the lens microcomputer 111 , and the adapter microcomputer 302 and a designation method of a communication counterpart in the P2P communication are described. Figure 6is a diagram illustrating a signal waveform obtained when the communication method is switched. Designation of a communication partner in P2P communication is performed through broadcast communication. In the following description, after the adapter microcomputer 302 is designated as the communication partner in P2P communication by the camera microcomputer 205, transmission from the camera microcomputer 205 and return from the adapter microcomputer 302 are performed through P2P communication. Subsequently, after the lens microcomputer 111 is designated as the communication partner in P2P communication by the camera microcomputer 205, transmission from the camera microcomputer 205 and return from the lens microcomputer 111 are performed through P2P communication.

[0063] First, the camera microcomputer 205 serving as a communication master device Figure 4 The described process performs broadcast communication. The data to be notified (sent) in this broadcast communication is sub-device designation data (communication counterpart designation data) for designating the counterpart that communicates with the camera microcomputer 205 in the next P2P communication. The lens microcomputer 111 and the adapter microcomputer 302 serving as communication sub-devices each determine whether the lens microcomputer 111 and the adapter microcomputer 302 are designated as the communication counterpart in the P2P communication based on the sub-device designation data received in the broadcast communication. In the camera microcomputer 205 and the designated communication sub-device, the communication is switched from the broadcast communication to the P2P communication through the broadcast communication. Since the adapter microcomputer 302 is designated as the communication counterpart in this case, according to the reference Figure 5 The described process performs data transmission and reception by P2P communication between the camera microcomputer 205 and the adapter microcomputer 302. As described above, the camera microcomputer 205 first transmits data to the adapter microcomputer 302, and then the adapter microcomputer 302 transmits data to the camera microcomputer 205.

[0064] When the P2P communication between the camera microcomputer 205 and the adapter microcomputer 302 ends, the camera microcomputer 205 specifies the lens microcomputer 111 as the communication partner in the P2P communication by using broadcast communication. Through broadcast communication, the adapter microcomputer 302 ends the P2P communication, and the lens microcomputer 111 switches from broadcast communication to P2P communication. If the broadcast communication is not performed, the P2P communication between the camera microcomputer 205 and the adapter microcomputer 302 is continued. In this example, the above-mentioned broadcast communication is performed, thereby Figure 5The described process performs data transmission and reception by P2P communication between the camera microcomputer 205 and the lens microcomputer 111. As described above, the camera microcomputer 205 first transmits data to the lens microcomputer 111, and then the lens microcomputer 111 transmits data to the camera microcomputer 205.

[0065] <Processing Flow of Broadcast Communication and P2P Communication>

[0066] The procedures (processing flow) of broadcast communication and P2P communication performed among the camera microcomputer 205, the lens microcomputer 111, and the adapter microcomputer 302 will be described. Figure 7 and Figure 8 Describe the processing flow in broadcast communication. Figure 7 is a diagram illustrating a flow of processing to be performed by a communication master device in broadcast communication. Figure 8 is a diagram illustrating a flow of processing to be performed by a communication sub-device in broadcast communication.

[0067] The following describes the flow of processing performed by the camera microcomputer 205 serving as the communication master. In step S100, the camera microcomputer 205 determines whether an event for starting broadcast communication has occurred. If this event has occurred ("Yes" in step S100), the process proceeds to step S101. If this event has not occurred ("No" in step S100), the process in step S100 is repeated.

[0068] In step S101, the camera microcomputer 205 turns on (connects) the ground switch 2081 and starts outputting Lo to the signal line CS. This notifies the lens microcomputer 111 and the adapter microcomputer 302 of the start of broadcast communication.

[0069] In step S102 , the camera microcomputer 205 operates the input-output changeover switch 2082 , and connects the signal line DATA to the data output unit of the camera microcomputer 205 .

[0070] In step S103 , the camera microcomputer 205 starts data transmission.

[0071] In step S104, the camera microcomputer 205 determines whether the data transmitted in step S103 includes a send request command. The send request command is a command for requesting the communication sub-device that has received data transmitted from the camera microcomputer 205 serving as the communication master to transmit data to the camera microcomputer 205. If the send request command is included ("Yes" in step S104), the process proceeds to step S106. If the send request command is not included ("No" in step S104), the process proceeds to step S105.

[0072] In step S105 , the camera microcomputer 205 turns off (blocks) the ground switch 2081 , and cancels the Lo output to the signal line CS.

[0073] In step S106 , the camera microcomputer 205 operates the input-output changeover switch 2082 , and connects the signal line DATA to the data input unit of the camera microcomputer 205 .

[0074] In step S107 , the camera microcomputer 205 turns off (blocks) the ground switch 2081 , and cancels the Lo output to the signal line CS.

[0075] In step S108, the camera microcomputer 205 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S108), the process proceeds to step S109. If the signal level is not Hi ("No" in step S108), the process in step S108 is repeated.

[0076] In step S109, the camera microcomputer 205 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S109), the process proceeds to step S110. If the signal level is not Lo ("No" in step S109), the process in step S109 is repeated.

[0077] In step S110 , the camera microcomputer 205 allows reception of data from the signal line DATA.

[0078] In step S111, the camera microcomputer 205 determines whether reception of the start bit from the signal line DATA is detected. If reception of the start bit is detected ("Yes" in step S111), the process proceeds to step S112. If reception of the start bit is not detected ("No" in step S111), the process in step S111 is repeated.

[0079] In step S112 , the camera microcomputer 205 turns on (connects) the ground switch 2081 , and starts Lo output to the signal line CS.

[0080] In step S113, the camera microcomputer 205 determines whether all the data has been received. If all the data has been received ("Yes" in step S113), the process proceeds to step S114. If all the data has not been received ("No" in step S113), the process in step S113 is repeated.

[0081] In step S114 , the camera microcomputer 205 prohibits reception of data from the signal line DATA.

[0082] In step S115 , the camera microcomputer 205 turns off (blocks) the ground switch 2081 , and cancels the Lo output to the signal line CS.

[0083] In step S116, the camera microcomputer 205 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S116), the process proceeds to step S117. If the signal level is not Hi ("No" in step S116), the process in step S116 is repeated.

[0084] In step S117, the camera microcomputer 205 determines whether the data transmitted in step S103 is child device designation data that designates the communication partner. If the data is child device designation data ("Yes" in step S117), the process proceeds to step S118. If the data is not child device designation data ("No" in step S117), the process ends.

[0085] In step S118 , the camera microcomputer 205 switches the communication method from the broadcast communication method to the P2P communication method.

[0086] Now, description will be given of a process flow of the adapter microcomputer 302 serving as a communication sub-device. Since the process flow of the lens microcomputer 111 serving as a communication sub-device is similar to that of the adapter microcomputer 302, description will be omitted.

[0087] In step S200, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S200), the process proceeds to step S201. If the signal level is not Lo ("No" in step S200), the process in step S200 is repeated.

[0088] In step S201, the adapter microcomputer 302 allows reception of data from the signal line DATA as broadcast communication.

[0089] In step S202, the adapter microcomputer 302 determines whether or not the reception of the start bit from the signal line DATA is detected. If the reception of the start bit is detected ("Yes" in step S202), the process proceeds to step S205. If the reception of the start bit is not detected ("No" in step S202), the process proceeds to step S203.

[0090] In step S203, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S203), the process proceeds to step S204. If the signal level is not Hi ("No" in step S203), the process returns to step S202.

[0091] In step S204, the adapter microcomputer 302 prohibits reception of data from the signal line DATA.

[0092] The processing in steps S203 and S204 is performed to cope with the case where P2P communication is performed between the camera microcomputer 205 and the lens microcomputer 111 and only the adapter microcomputer 302 performs broadcast communication. In this case, the adapter microcomputer 302 does not receive data from the camera microcomputer 205.

[0093] In step S205, the adapter microcomputer 302 turns on (connects) the ground switch 3031, and starts outputting Lo to the signal line CS.

[0094] In step S206, the adapter microcomputer 302 determines whether all the data has been received. If all the data has been received ("Yes" in step S206), the process proceeds to step S207. If all the data has not been received ("No" in step S206), the process in step S206 is repeated.

[0095] In step S207, the adapter microcomputer 302 prohibits reception of data from the signal line DATA.

[0096] In step S208, the adapter microcomputer 302 turns off (blocks) the ground switch 3031, and cancels the Lo output to the signal line CS.

[0097] In step S209, the adapter microcomputer 302 determines whether the data received in step S206 includes a transmission request command. If a transmission request command is included ("Yes" in step S209), the process proceeds to step S210. If a transmission request command is not included ("No" in step S209), the process proceeds to step S215.

[0098] In step S210, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S210), the process proceeds to step S211. If the signal level is not Hi ("No" in step S210), the process in step S210 is repeated.

[0099] In step S211, the adapter microcomputer 302 turns on (connects) the ground switch 3031, and starts outputting Lo to the signal line CS.

[0100] In step S212 , the adapter microcomputer 302 operates the input-output changeover switch 3032 and connects the signal line DATA to the data output unit of the adapter microcomputer 302 .

[0101] In step S213, the adapter microcomputer 302 starts data transmission.

[0102] In step S214, the adapter microcomputer 302 turns off (blocks) the ground switch 3031, and cancels the Lo output to the signal line CS.

[0103] In step S215, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S215), the process proceeds to step S216. If the signal level is not Hi ("No" in step S215), the process in step S215 is repeated.

[0104] In step S216, the adapter microcomputer 302 determines whether the data received in step S206 is child device designation data and whether the adapter microcomputer 302 is designated as the communication partner of the camera microcomputer 205 in P2P communication. If the data is child device designation data and the adapter microcomputer 302 is designated as the communication partner ("Yes" in step S216), the process proceeds to step S217. If the data is not child device designation data, or if the adapter microcomputer 302 is not designated as the communication partner ("No" in step S216), the process ends.

[0105] In step S217 , the adapter microcomputer 302 switches the communication method from the broadcast communication method to the P2P communication method.

[0106] Will refer to Figure 9 、 Figure 10A and Figure 10B The following describes the flow of processing in general P2P communication. Figure 9 This is a diagram illustrating a processing flow of a communication master device in P2P communication. Figure 10A and Figure 10B A diagram illustrating a processing flow of a communication sub-device in an example P2P communication.

[0107] First, the processing flow of the camera microcomputer 205 serving as the communication master will be described. In step S300, the camera microcomputer 205 determines whether an event for starting P2P communication has occurred. If this event has occurred ("Yes" in step S300), the process proceeds to step S301. If this event has not occurred ("No" in step S300), the process in step S300 is repeated.

[0108] In step S301 , the camera microcomputer 205 operates the input-output changeover switch 2082 , and connects the signal line DATA to the data output unit of the camera microcomputer 205 .

[0109] In step S302, the camera microcomputer 205 determines whether to execute transmission in the P2P burst communication executed by the communication master. If transmission is to be executed ("Yes" in step S302), the process proceeds to step S303. If transmission is not to be executed ("No" in step S302), the process proceeds to step S304.

[0110] In step S303, the camera microcomputer 205 executes transmission in P2P burst communication executed by the communication master, and then the process proceeds to step S305. Details of transmission in P2P burst communication executed by the communication master will be described below.

[0111] In step S304 , the camera microcomputer 205 starts data transmission.

[0112] In step S305 , the camera microcomputer 205 turns on (connects) the ground switch 2081 , and starts Lo output to the signal line CS.

[0113] In step S306, the camera microcomputer 205 determines whether the data transmitted in step S304 includes a transmission request command. If a transmission request command is included ("Yes" in step S306), the process proceeds to step S309. If a transmission request command is not included ("No" in step S306), the process proceeds to step S307.

[0114] In step S307 , the camera microcomputer 205 turns off (blocks) the ground switch 2081 , and cancels the Lo output to the signal line CS.

[0115] In step S308, the camera microcomputer 205 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S308), the process proceeds to step S316. If the signal level is not Lo ("No" in step S308), the process in step S308 is repeated.

[0116] In step S309 , the camera microcomputer 205 operates the input-output changeover switch 2082 , and connects the signal line DATA to the data input unit of the camera microcomputer 205 .

[0117] In step S311 , the camera microcomputer 205 turns off (blocks) the ground switch 2081 , and cancels the Lo output to the signal line CS.

[0118] In step S312, the camera microcomputer 205 determines whether to perform reception in the P2P burst communication performed by the communication master. If reception is to be performed ("Yes" in step S312), the process proceeds to step S313. If reception is not to be performed ("No" in step S312), the process proceeds to step S314.

[0119] In step S313, the camera microcomputer 205 performs reception in the P2P burst communication performed by the communication master, and then the process proceeds to step S315. The processing details of reception in the P2P burst communication performed by the communication master will be described below.

[0120] In step S314, the camera microcomputer 205 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S314), the process proceeds to step S315. If the signal level is not Lo ("No" in step S314), the process in step S314 is repeated.

[0121] In step S315 , the camera microcomputer 205 analyzes the data received from the signal line DATA.

[0122] In step S316, the camera microcomputer 205 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S316), the process proceeds to step S317. If the signal level is not Hi ("No" in step S316), the process in step S316 is repeated.

[0123] In step S317, the camera microcomputer 205 determines whether a broadcast communication event has occurred. If the event has occurred (YES in step S317), the process proceeds to step S318. If the event has not occurred (NO in step S317), the process ends.

[0124] In step S318 , the camera microcomputer 205 switches the communication from P2P communication to broadcast communication.

[0125] Next, the process flow of the adapter microcomputer 302 serving as a communication sub-device will be described. Since the process flow of the lens microcomputer 111 serving as a communication sub-device is similar to that of the adapter microcomputer 302, the description will be omitted. In step S400, the adapter microcomputer 302 allows data to be received from the signal line DATA as P2P communication.

[0126] In step S401, the adapter microcomputer 302 determines whether to perform reception in the P2P burst communication performed by the communication sub-device. If reception is to be performed ("Yes" in step S401), the process proceeds to step S402. If reception is not to be performed ("No" in step S401), the process proceeds to step S403.

[0127] In step S402, the adapter microcomputer 302 performs reception in the P2P burst communication performed by the communication sub-device, and then the process proceeds to step S404. The details of the processing of reception in the P2P burst communication performed by the communication sub-device will be described below.

[0128] In step S403, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S403), the process proceeds to step S404. If the signal level is not Lo ("No" in step S403), the process in step S403 is repeated.

[0129] In step S404, the adapter microcomputer 302 permits reception of data from the signal line DATA as broadcast communication.

[0130] In step S405, the adapter microcomputer 302 analyzes the data received from the signal line DATA.

[0131] In step S406, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S406), the process proceeds to step S408. If the signal level is not Hi ("No" in step S406), the process proceeds to step S407.

[0132] In step S407, the adapter microcomputer 302 determines whether or not reception of the start bit from the signal line DATA is detected. If reception of the start bit is detected ("Yes" in step S407), the process proceeds to step S420. If reception of the start bit is not detected ("No" in step S407), the process returns to step S406.

[0133] In step S408, the adapter microcomputer 302 determines whether the data received in step S405 includes a transmission request command. If a transmission request command is included ("Yes" in step S408), the process proceeds to step S409. If a transmission request command is not included ("No" in step S408), the process proceeds to step S414.

[0134] In step S409 , the adapter microcomputer 302 operates the input-output changeover switch 3032 and connects the signal line DATA to the data output unit of the adapter microcomputer 302 .

[0135] In step S410, the adapter microcomputer 302 determines whether to execute transmission in the P2P burst communication executed by the communication sub-device. If transmission is to be executed ("Yes" in step S410), the process proceeds to step S411. If transmission is not to be executed ("No" in step S410), the process proceeds to step S412.

[0136] In step S411, the adapter microcomputer 302 performs transmission in the P2P burst communication performed by the communication sub-device, and then the process proceeds to step S413. The processing details of transmission in the P2P burst communication performed by the communication sub-device will be described below.

[0137] In step S412, the adapter microcomputer 302 starts data transmission.

[0138] In step S413 , the adapter microcomputer 302 operates the input-output changeover switch 3032 and connects the signal line DATA to the data input unit of the adapter microcomputer 302 .

[0139] In step S414, the adapter microcomputer 302 turns on (connects) the ground switch 3031, and starts outputting Lo to the signal line CS.

[0140] In step S415, the adapter microcomputer 302 permits reception of data from the signal line DATA as broadcast communication.

[0141] In step S416, the adapter microcomputer 302 turns off (blocks) the ground switch 3031, and cancels the Lo output to the signal line CS.

[0142] In step S417, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S417), the process proceeds to step S419. If the signal level is not Hi ("No" in step S417), the process proceeds to step S418.

[0143] In step S418, the adapter microcomputer 302 determines whether reception of a start bit from the signal line DATA is detected. When reception of the start bit is detected (Yes in step S418), the process advances to step S420. When reception of the start bit is not detected (No in step S418), the process returns to step S417.

[0144] In step S419, the adapter microcomputer 302 performs processing based on the received data analyzed in step S405. After performing the processing in step S419, P2P communication can be continued by restarting the process.

[0145] In step S420, the adapter microcomputer 302 interrupts the processing of P2P communication. Thereafter, the process advances to Figure 8 step S205 therein to perform broadcast communication.

[0146] As described above, the communication partner in P2P communication can be specified by broadcast communication, and switching between broadcast communication and P2P communication can be performed.

[0147] Here, the size of data that can be transmitted in one P2P communication is limited by the size of the reception buffer on the reception side, so the data size is insufficient. Although data with a sufficient data size can be transmitted by repeating normal P2P communication, in normal P2P communication, the communication master device and the communication slave device alternately perform data transmission and standby requests via the signal line CS, thus requiring an excessive transmission time. To solve this problem, the P2P burst communication described below is useful.

[0148] <P2P Burst Communication Method (Third Communication Method)>

[0149] Reference will be made to Figures 11 to 13 describe the P2P burst communication to be performed between the camera microcomputer 205 and the adapter microcomputer 302. Figure 11 is a diagram illustrating the signal waveform in P2P burst communication (communication slave device transmits). In Figure 11 the adapter microcomputer 302 is specified as the communication partner in P2P communication by the camera microcomputer 205 in broadcast communication. Thereafter, normal P2P communication including transmission from the camera microcomputer 205 and return from the adapter microcomputer 302 is performed. However, thereafter, the camera microcomputer 205 transmits a command for switching to the P2P burst communication method (third communication method). Thereby, the communication method is switched from the second communication method to the third communication method, and data transmission (communication slave device transmits) in P2P burst communication, which is one-way communication from the adapter microcomputer 302 to the camera microcomputer 205, is performed.

[0150] Already referenced Figure 6 The process of specifying a communication partner in P2P communication and normal P2P communication (P2P communication that does not use the P2P burst communication method) are described, so the description will be omitted. In normal P2P communication, information about communication rules (also called communication, protocol, communication protocol or communication conditions) for P2P burst communication to be performed thereafter is shared. In the P2P burst communication method (the third communication method), data communication is performed in data block units having a specific data size. The data block unit can be a unit of a specific number or a variable number of data blocks. Therefore, the communication rule information may include a block size, an inter-block waiting time (wait time), the number of blocks until flow control, and the total size, but the communication rule information is not limited to these.

[0151] A block refers to a unit (group) for collectively or collectively transmitting data using the P2P burst communication method, and a block size refers to the number of bytes in one block. In this example, the block size is set to 16 bytes as the size of data that can be continuously received by the camera microcomputer 205 on the receiving side of the P2P burst communication. The inter-block wait time is the time until the adapter microcomputer 302 on the transmitting side of the P2P burst communication starts transmitting the next block after completing the transmission of one block. In this example, the inter-block wait time is the time until the camera microcomputer 205 on the receiving side of the P2P burst communication becomes able to receive the next block after completing the reception of one block, and is set to 100μs.

[0152] Flow control in P2P burst communication can be achieved by the camera microcomputer 205 on the receiving side of P2P burst communication issuing a communication timing notification using the signal line CS. For example, the camera microcomputer 205 needs to allocate resources for processing other than P2P burst communication, so it avoids issuing a communication timing notification (issuing a communication standby request; executing a communication standby process) until the processing is complete. By avoiding issuing a notification, time for processing other than communication can be secured.

[0153] The number of blocks until flow control is the number of blocks to be exchanged from the start of P2P burst communication until flow control timing (or between one flow control and the next flow control). In this example, the number of blocks is the number of blocks that enables the camera microcomputer 205 on the receiving side of P2P burst communication to complete processing other than P2P burst communication within the above-mentioned standby time, and is set to 4. The total size is the size of all data to be transmitted in P2P burst communication by the adapter microcomputer 302 on the transmitting side of P2P burst communication.

[0154] The camera microcomputer 205 transmits a command for conversion to P2P burst communication (communication sub-device transmission) to the adapter microcomputer 302. Then, the adapter microcomputer 302 performs P2P burst communication (communication sub-device transmission) with the camera microcomputer 205 according to the above-mentioned communication rule information.

[0155] Specifically, the camera microcomputer 205 transmits a command for switching to P2P burst communication (communication sub-device transmission) to the adapter microcomputer 302 using the signal line DATA. The camera microcomputer 205 then notifies the adapter microcomputer 302 of the end of transmission and a standby request for the next data transmission using the signal line CS. When the adapter microcomputer 302 receives the command for switching to P2P burst communication (communication sub-device transmission), the adapter microcomputer 302 generates data to be transmitted in the P2P burst communication (communication sub-device transmission).

[0156] When the camera microcomputer 205 completes the arrangement for reception in P2P burst communication, it cancels the communication (data transmission) standby request issued by the request signal on the signal line CS. When the generation of the data to be transmitted is complete and the standby request issued by the request signal from the camera microcomputer 205 is canceled, the adapter microcomputer 302 transmits data corresponding to one block (16-byte block size). Thereafter, the adapter microcomputer 302 stops communication for a period of at least the inter-block wait time (100 μs). When the camera microcomputer 205 receives data corresponding to one block, it executes processing for receiving the next data corresponding to one block within the inter-block wait time.

[0157] After starting P2P burst communication or executing flow control, the camera microcomputer 205 and the adapter microcomputer 302 execute the communication process corresponding to one block four times (corresponding to four blocks as the "number of blocks until flow control"). When data transmission corresponding to the number of blocks until flow control is completed, the adapter microcomputer 302 waits for flow control from the camera microcomputer 205. When data reception corresponding to the number of blocks until flow control is completed, the camera microcomputer 205 outputs a standby request signal on the signal line CS to notify the interruption of reception and the standby request for data transmission. When the arrangement of data reception in P2P burst communication is completed, the camera microcomputer 205 cancels the standby request signal on the signal line CS and completes flow control.

[0158] The camera microcomputer 205 and the adapter microcomputer 302 perform communication processing until the data transfer corresponding to the total size is completed, while inserting flow control. When the reception corresponding to the total size is completed, the camera microcomputer 205 waits for a standby request signal on the signal line CS for notifying the end of transmission and the standby request for data transmission to be issued by the adapter microcomputer 302. When the data transfer corresponding to the total size is completed, the adapter microcomputer 302 outputs a standby request signal for notifying the end of transmission and the standby request for data transmission on the signal line CS, and then cancels the standby request signal. Thereby, the P2P burst communication (communication sub-device transmission) is completed.

[0159] <Processing flow in P2P burst communication (communication sub-device transmission)>

[0160] Refer to Figure 12 and Figure 13 to describe the processing flow in P2P burst communication (sub-device transmission). Figure 12 is a diagram illustrating the processing flow of the communication master device in P2P burst communication (communication sub-device transmission). Figure 13 is a diagram illustrating the processing flow of the communication sub-device in P2P burst communication (communication sub-device transmission). First, refer to Figure 12 to describe the processing flow of the camera microcomputer 205 serving as the communication master device.

[0161] In step S500, the camera microcomputer 205 performs the reception processing of data, and the processing proceeds to step S501.

[0162] In step S501, the camera microcomputer 205 determines whether the data reception corresponding to the total size is completed. If the data reception has been completed (\"Yes\" in step S501), the processing proceeds to step S511. If the data reception has not been completed (\"No\" in step S501), the processing proceeds to step S502.

[0163] In step S502, the camera microcomputer 205 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo (\"Yes\" in step S502), the processing ends. If the signal level is not Lo (\"No\" in step S502), the processing proceeds to step S503.

[0164] In step S503, the camera microcomputer 205 determines whether the data reception corresponding to the block size is completed. If the data reception has been completed (\"Yes\" in step S503), the processing proceeds to step S504. If the data reception has not been completed (\"No\" in step S503), the processing returns to step S500.

[0165] In step S504, the camera microcomputer 205 determines whether data reception corresponding to the number of blocks up to flow control has been completed. If data reception has been completed ("Yes" in step S504), the process proceeds to step S507. If data reception has not been completed ("No" in step S504), the process proceeds to step S505.

[0166] In step S505, the camera microcomputer 205 determines whether it is necessary to execute processing other than communication. If it is necessary to execute processing ("Yes" in step S505), the process proceeds to step S507. If it is not necessary to execute processing ("No" in step S505), the process proceeds to step S506.

[0167] In step S506, the camera microcomputer 205 performs received data processing in P2P burst communication. The process then returns to step S500. Received data processing is a process that stores received data and enables the next block of data to be received. This processing must be completed within the aforementioned inter-block wait time.

[0168] In step S507, the camera microcomputer 205 turns on (connects) the ground switch 2081, and starts Lo output to the signal line CS.

[0169] In step S508 , the camera microcomputer 205 performs received data processing similar to the processing in step S506 .

[0170] In step S509 , the camera microcomputer 205 executes processing other than communication.

[0171] In step S510 , the camera microcomputer 205 turns off (blocks) the ground switch 2081 , and cancels the Lo output to the signal line CS.

[0172] In step S511, the camera microcomputer 205 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S511), the process ends. If the signal level is not Lo ("No" in step S511), the process in step S511 is repeated.

[0173] Will refer to Figure 13 The processing flow of the adapter microcomputer 302 serving as a communication sub-device is described.The processing flow of the lens microcomputer 111 serving as a communication sub-device is similar to the processing to be performed by the adapter microcomputer 302, and thus the description will be omitted.

[0174] In step S600, the adapter microcomputer 302 starts data transmission.

[0175] In step S601, the adapter microcomputer 302 determines whether the data transmission corresponding to the total size has been completed. If the data transmission has been completed ("Yes" in step S601), the process ends. If the data transmission has not been completed ("No" in step S601), the process proceeds to step S602.

[0176] In step S602, the adapter microcomputer 302 determines whether data transmission corresponding to the block size has been completed. If data transmission has been completed ("Yes" in step S602), the process proceeds to step S603. If data transmission has not been completed ("No" in step S602), the process returns to step S600.

[0177] In step S603, the adapter microcomputer 302 determines whether data transmission corresponding to the number of blocks until flow control is completed. If data transmission has been completed ("Yes" in step S603), the process proceeds to step S607. If data transmission has not been completed ("No" in step S603), the process proceeds to step S604.

[0178] In step S604, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S604), the process proceeds to step S606. If the signal level is not Lo ("No" in step S604), the process proceeds to step S605.

[0179] In step S605, the adapter microcomputer 302 determines whether the inter-block waiting time has elapsed. If the inter-block waiting time has elapsed ("Yes" in step S605), the process returns to step S600. If the inter-block waiting time has not elapsed ("No" in step S605), the process returns to step S604.

[0180] In step S606, the adapter microcomputer 302 operates the input-output changeover switch 3032, and connects the signal line DATA to the data input unit of the adapter microcomputer 302. Then, the process proceeds to step S609.

[0181] In step S607 , the adapter microcomputer 302 operates the input-output changeover switch 3032 , and connects the signal line DATA to the data input unit of the adapter microcomputer 302 .

[0182] In step S608, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S608), the process proceeds to step S609. If the signal level is not Lo ("No" in step S608), the process in step S608 is repeated.

[0183] In step S609, the adapter microcomputer 302 permits reception of data from the signal line DATA in the broadcast communication.

[0184] In step S610, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S610), the process proceeds to step S612. If the signal level is not Hi ("No" in step S610), the process proceeds to step S611.

[0185] In step S611, the adapter microcomputer 302 determines whether or not reception of the start bit from the signal line DATA is detected. If reception of the start bit is detected ("Yes" in step S611), the process proceeds to step S613. If reception of the start bit is not detected ("No" in step S611), the process returns to step S610.

[0186] In step S612 , the adapter microcomputer 302 operates the input-output changeover switch 3032 and connects the signal line DATA to the data output unit of the adapter microcomputer 302 .

[0187] In step S613, the adapter microcomputer 302 interrupts the processing of the P2P communication. Then, the processing proceeds to Figure 8 Step S205 is performed to perform broadcast communication.

[0188] Will refer to Figure 8The following describes the operations to be performed by the lens microcomputer 111 while the camera microcomputer 205 and the adapter microcomputer 302 are performing P2P burst communication with each other. If the adapter microcomputer 302 is designated as the communication partner for P2P communication in the broadcast communication performed by the camera microcomputer 205, the lens microcomputer 111 determines in step S216 that it has not been designated as the communication device. Therefore, the lens microcomputer 111 does not switch to the P2P communication method. Therefore, in subsequent normal P2P communication and subsequent P2P burst communication, when the signal level of the signal line CS is set to Lo, the signal level of the signal line DATA is not set to a level other than Hi. In step S202, reception of the start bit is not determined, and processing proceeds sequentially to steps S200, S201, S202, S203, and S204. In other words, even when a communication sub-device such as the lens microcomputer 111 that is not a communication partner of P2P burst communication is connected, the camera microcomputer 205 and the adapter microcomputer 302 can perform P2P burst communication. As described above, when the adapter microcomputer 302 is designated as the communication partner in P2P communication, the processing of the lens microcomputer 111 does not include a process for determining whether to switch to P2P burst communication (processing similar to the process in step S401). Therefore, even when a conventional interchangeable lens (lens microcomputer) that supports only broadcast communication and normal P2P communication is connected, the camera microcomputer 205 and the adapter microcomputer 302 can perform P2P burst communication without any problems.

[0189] As described above, in this exemplary embodiment, in a system that performs communication using two signal lines corresponding to the signal line CS and the signal line DATA, the signal to be transmitted on the signal line CS switches between the broadcast communication method and the P2P communication method. With this configuration, it is possible to implement multiple communication methods for communication between the camera microcomputer 205 and the lens microcomputer 111 or the adapter microcomputer 302 without increasing the number of signal lines. P2P burst communication (communication sub-device transmission) that is different from normal P2P communication can also be implemented without increasing the number of signal lines.

[0190] <Switch to P2P burst communication mode (sending by the communication master)>

[0191] Will refer to Figures 14 to 16 Another example of switching of the P2P burst communication and the P2P burst communication to be performed between the camera microcomputer 205 and the adapter microcomputer 302 is described. Figure 14 1 is a diagram illustrating a signal waveform in P2P burst communication (communication master transmission). Figure 15This is a diagram illustrating a processing flow of the communication master in P2P burst communication (communication master transmission). Figure 16 This is a diagram illustrating a processing flow of a communication slave device in P2P burst communication (communication master device transmission).

[0192] Figure 14 The figure shows the signal waveform in P2P burst communication for performing data transmission from the camera microcomputer 205 serving as the communication master to the adapter microcomputer 302 serving as the communication slave. In this example, in the broadcast communication performed by the camera microcomputer 205, the adapter microcomputer 302 is designated as the communication partner in the P2P communication, and then normal P2P communication including transmission from the camera microcomputer 205 and response from the adapter microcomputer 302 is performed. Thereafter, data transmission is performed from the camera microcomputer 205 through P2P burst communication (communication master transmission), and then response regarding the data transmission is performed from the adapter microcomputer 302 to the camera microcomputer 205.

[0193] The above has been referenced Figure 6 The process of specifying the communication counterpart in P2P communication and general P2P communication is described, so the description will be omitted. In P2P communication, information about the communication rules for the P2P burst communication (communication master device transmission) to be performed thereafter is shared. The type of communication rule information can be the same as the type of communication rule information in the above-mentioned P2P burst communication (communication sub-device transmission). In this example, the communication rule information includes block size, inter-block waiting time, the number of blocks until flow control, and the total size. In this example, the block size is set to 8 bytes as the size of data that the adapter microcomputer 302 on the receiving side of the P2P burst communication can continuously receive. In this example, the inter-block waiting time is set to 150μs. Since the number of blocks until flow control is 1 in this example, flow control is always performed after one block is sent. Therefore, the inter-block waiting time is not used. The total size is the size of the data to be sent by the camera microcomputer 205 to the adapter microcomputer 302 in the P2P burst communication (communication master device transmission).

[0194] When the adapter microcomputer 302 performs a return in P2P communication for sharing rule information, the adapter microcomputer 302 makes arrangements for data reception in P2P burst communication (sent by the communication master device). When the arrangements are completed, the adapter microcomputer 302 cancels the standby request signal for data transmission on the signal line CS. Based on the cancellation of the standby request signal performed by the adapter microcomputer 302, the camera microcomputer 205 starts P2P burst communication (sent by the communication master device) and transmits data corresponding to one block (block size: 8 bytes). Since the number of blocks until flow control is 1, after one block is transmitted, flow control is performed by the adapter microcomputer 302 without waiting for the inter-block waiting time.

[0195] When the data reception corresponding to the number of blocks until flow control is completed, the adapter microcomputer 302 outputs a standby request signal indicating the interruption of reception and the request for data transmission standby to the signal line CS. Then, when the arrangements for data reception in P2P burst communication (sent by the communication master device) are completed, the adapter microcomputer 302 cancels the standby request signal on the signal line CS.

[0196] The camera microcomputer 205 and the adapter microcomputer 302 repeat the above processing until flow control until the data communication corresponding to the total size is completed. When the data reception corresponding to the total size is completed, the adapter microcomputer 302 waits for the standby request signal indicating the end of transmission and the request for data transmission standby output by the camera microcomputer 205 to the signal line CS. When the data transmission corresponding to the total size is completed, the camera microcomputer 205 outputs a standby request signal to the signal line CS. Based on the cancellation of the standby request signal performed by the camera microcomputer 205, the adapter microcomputer 302 performs data transmission regarding the reception result in P2P burst communication (sent by the communication master device). Then, the adapter microcomputer 302 outputs a standby request signal indicating the end of transmission and the request for data transmission standby to the signal line CS and cancels the standby request signal. Thereby, P2P burst communication (sent by the communication master device) ends.

[0197] <Processing flow in P2P burst communication (sent by the communication master device)>

[0198] Reference will be made Figure 15 and Figure 16 to describe the processing flow in P2P burst communication (sent by the communication master device). Figure 15 is a diagram illustrating the processing flow of the communication master device in P2P burst communication (sent by the communication master device). Figure 16 is a diagram illustrating the processing flow of the communication slave device in P2P burst communication (sent by the communication master device).

[0199] Now, reference will be made Figure 15 The following describes a processing flow of the camera microcomputer 205 serving as a communication master. In step S700, the camera microcomputer 205 starts data transmission.

[0200] In step S701, the camera microcomputer 205 determines whether the data transmission corresponding to the total size has been completed. If the data transmission has been completed ("Yes" in step S701), the process ends. If the data transmission has not been completed ("No" in step S701), the process proceeds to step S702.

[0201] In step S702, the camera microcomputer 205 determines whether data transmission corresponding to the block size has been completed. If data transmission has been completed ("Yes" in step S702), the process proceeds to step S703. If data transmission has not been completed ("No" in step S702), the process returns to step S700.

[0202] In step S703, the camera microcomputer 205 determines whether data transmission corresponding to the number of blocks until flow control has been completed. If data transmission has been completed ("Yes" in step S703), the process proceeds to step S706. If data transmission has not been completed ("No" in step S703), the process proceeds to step S704.

[0203] In step S704, the camera microcomputer 205 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo (YES in step S704), the process proceeds to step S707. If the signal level is not Lo (NO in step S704), the process proceeds to step S705.

[0204] In step S705, the camera microcomputer 205 determines whether the inter-block waiting time has elapsed. If the inter-block waiting time has elapsed ("Yes" in step S705), the process returns to step S700. If the inter-block waiting time has not elapsed ("No" in step S705), the process returns to step S704.

[0205] In step S706, the camera microcomputer 205 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo (YES in step S706), the process proceeds to step S707. If the signal level is not Lo (NO in step S706), the process in step S706 is repeated.

[0206] In step S707, the camera microcomputer 205 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi (Yes in step S707), the process returns to step S700. If the signal level is not Hi (No in step S707), the process in step S707 is repeated.

[0207] Will refer to Figure 16 The processing flow of the adapter microcomputer 302 serving as a communication sub-device is described. Since the processing flow of the lens microcomputer 111 is similar to the processing to be performed by the adapter microcomputer 302, the description will be omitted. In step S800, the adapter microcomputer 302 performs reception processing of data.

[0208] In step S801, the adapter microcomputer 302 determines whether data reception corresponding to the total size has been completed. If data reception has been completed ("Yes" in step S801), the process proceeds to step S816. If data reception has not been completed ("No" in step S801), the process proceeds to step S802.

[0209] In step S802, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Lo. If the signal level is Lo ("Yes" in step S802), the process ends. If the signal level is not Lo ("No" in step S802), the process proceeds to step S803.

[0210] In step S803, the adapter microcomputer 302 determines whether data reception corresponding to the block size has been completed. If data reception has been completed ("Yes" in step S803), the process proceeds to step S804. If data reception has not been completed ("No" in step S803), the process returns to step S800.

[0211] In step S804, the adapter microcomputer 302 determines whether data reception corresponding to the number of blocks until flow control has been completed. If data reception has been completed ("Yes" in step S804), the process proceeds to step S807. If data reception has not been completed ("No" in step S804), the process proceeds to step S805.

[0212] In step S805, the adapter microcomputer 302 determines whether or not it is necessary to execute processing other than communication. If it is necessary to execute processing other than communication ("Yes" in step S805), the process proceeds to step S807. If it is not necessary to execute processing other than communication ("No" in step S805), the process proceeds to step S806.

[0213] In step S806, the adapter microcomputer 302 performs received data processing. Then, the process returns to step S800. The received data processing is a process for storing the received data and allowing the next block of data to be received. The processing needs to be completed within the above-mentioned inter-block waiting time.

[0214] In step S807, the adapter microcomputer 302 turns on (connects) the ground switch 2081, and starts outputting Lo to the signal line CS.

[0215] In step S808, the adapter microcomputer 302 permits reception of data from the signal line DATA in the broadcast communication.

[0216] In step S809 , the adapter microcomputer 302 performs received data processing similar to the processing in step S806 .

[0217] In step S810, the adapter microcomputer 302 performs processing other than communication.

[0218] In step S811, the adapter microcomputer 302 turns off (blocks) the ground switch 2081, and cancels the Lo output to the signal line CS.

[0219] In step S812, the adapter microcomputer 302 determines whether the signal level of the signal line CS is Hi. If the signal level is Hi ("Yes" in step S812), the process proceeds to step S814. If the signal level is not Hi ("No" in step S812), the process proceeds to step S813.

[0220] In step S813, the adapter microcomputer 302 determines whether or not reception of the start bit from the signal line DATA is detected. If reception of the start bit is detected ("Yes" in step S813), the process proceeds to step S815. If reception of the start bit is not detected ("No" in step S813), the process proceeds to step S812.

[0221] In step S814, the adapter microcomputer 302 allows data reception from the signal line DATA in the P2P communication.

[0222] In step S815, the adapter microcomputer 302 interrupts the P2P communication. Then, the process proceeds to Figure 8The operation to be performed by the lens microcomputer 111 while the camera microcomputer 205 and the adapter microcomputer 302 are performing P2P burst communication (communication master transmission) with each other is similar to the operation performed in the above-mentioned P2P burst communication (communication slave transmission). Therefore, the description of the operation will be omitted.

[0223] According to this exemplary embodiment, an auxiliary device that facilitates efficient data communication, which will be described below, can be provided. In P2P burst communication, data can be sent in a shorter time by removing a portion of the processing related to communication compared to normal P2P communication. Specifically, in the receiving device that receives the data, the processing related to the data communication for issuing a data request is reduced. In typical P2P communication, for each size of data that the receiving device can continuously receive (i.e., each block size), a data communication processing for issuing a data request is required. In contrast, in P2P burst communication, the data communication processing for issuing a data request is required only at the timing when the P2P burst communication starts.

[0224] Furthermore, the process of notifying the data communication timing via the signal line CS from the data transmitting device is reduced. In typical P2P communication, the transmitting device must perform this process for each block size. In contrast, in P2P burst communication, the transmitting device only needs to perform this process for notifying the data communication timing via the signal line CS at the end of the P2P burst communication.

[0225] In addition, the processing of notifying the data communication timing from the receiving device receiving the data via the signal line CS is reduced. In typical P2P communication, the receiving device is required to perform the processing of notifying the communication timing via the signal line CS for each block size. In contrast, in P2P burst communication, between blocks that do not require flow control, there is no need for the processing of notifying the communication timing via the signal line CS performed by the receiving device (the sending device performs an inter-block waiting process in which the sending device stops sending for a period of time of the inter-block waiting time). The inter-block waiting time is the time required for the receiving device to become able to receive the next block of data. This time can be set to a time shorter than the time required for the receiving device to perform the processing of notifying the communication timing via the signal line CS in typical P2P communication. Therefore, the communication time is reduced by replacing the notification process with the inter-block waiting process.

[0226] As described above, in P2P burst communication, data can be transmitted in a shorter time (ie, more efficiently) compared to normal P2P communication.

[0227] Next, the communication time required to transmit 4096 bytes of data in this exemplary embodiment when the communication rate is 1 Mbps will be exemplified. First, the communication time in a typical P2P communication will be described. Figure 3 As described above, the start bit ST, parity bit PA and stop bit SP are added to transmit 1 byte of information, and 11 bits of data transmission becomes necessary. When the communication speed is 1Mbps, it takes 11μs to transmit 11 bits of data. In typical P2P communication, such as Figure 5 As shown in the figure, the data request issued by the receiving device and the notification issued by the receiving device via the signal line CS (standby request issued by the request signal; standby processing of communication) and the data transmission performed by the transmitting device and the notification issued by the transmitting device via the signal line CS are repeated until the transmission of all data is completed. In the case of issuing a data request using 1-byte information, 11μs is required for the request. In the following notification issued via the signal line CS, 100μs is required from the data request to the timing when the level of the signal line CS is set to Lo, 100μs is required to keep the level at Lo, and 100μs is required from when the level is set to Hi until the next data is received. In other words, a total of 300μs is required at the shortest. Subsequently, it takes a minimum of 176μs for the transmitting device to send 16 bytes of data. Thereafter, the notification issued by the transmitting device via the signal line CS takes a minimum of 300μs as described above. In view of the above, in typical P2P communication, it takes 787 μs (the time interval between two request signals) to send 16 bytes of data. Therefore, it takes about 201 ms at the shortest to send 4096 bytes of information.

[0228] The communication time in P2P burst communication will be described. Figure 11As shown in the figure, a data request issued by the receiving device and a notification issued by the receiving device via the signal line CS, the sending of data corresponding to four blocks by the sending device while inserting three inter-block waiting times, and the notification issued by the receiving device via the signal line CS are executed. The data corresponding to the four blocks has an information volume of 64 bytes (communication information volume). The sending of data corresponding to the four blocks executed by the sending device and the notification issued by the receiving device via the signal line CS are repeated until the sending of all data is completed. The data request requires a communication time of 11μs. The following notification issued via the signal line CS requires 300μs. Subsequently, for the sending device, in order to send the data corresponding to the four blocks, the sending time corresponding to the four blocks and the three inter-block waiting times are required between one flow control (standby processing for communication) and the next flow control. In other words, 176μs×4+100μs×3=1004μs is required. The subsequent flow control requires the same time as the time required for the notification issued via the signal line CS. That is, the shortest time required is 300μs. Therefore, it takes 1304 μs (the time interval between two request signals) to send 64 bytes between one flow control and the next, and it takes a minimum of about 84 ms to send 4096 bytes of data. In view of the above, in this example, P2P burst communication can perform data transmission in a time equal to or less than half the time required in typical P2P communication.

[0229] As described above, according to this exemplary embodiment, for example, an accessory device can be provided that facilitates efficient data communication. This is because, in the third communication method, the ratio of the standby time required for a standby request signal to the time required for communication between the accessory device and the imaging device is lower than in the second communication method. Furthermore, in a system that performs communication using two signal lines, corresponding to the signal line CS and the signal line DATA, P2P burst communication can be implemented without adding signal lines. Here, efficient and normal data communication can be achieved by defining the receive buffer size in the receiving device as the block size and defining the time required for the receiving device to process data after transmitting data corresponding to one block as the inter-block wait time. Furthermore, a number of blocks is defined for flow control, and after transmitting data corresponding to the number of blocks, flow control is performed so that data transmission by the transmitting device (transmitting device) waits for the time required by the receiving device (receiving device). With this configuration, the receiving device can simultaneously perform processing other than communication. Unlike typical P2P communication, in P2P burst communication, the transmitting device among the communication master and communication slave devices transmits data via the signal line DATA, and the receiving device transmits a signal for flow control via the signal line CS. Therefore, P2P burst communication can shorten the communication time compared to typical P2P communication. In flow control, time is reserved for processing other than communication. Therefore, the time the signal line CS is held at the Lo level increases. Therefore, from the perspective of P2P burst communication efficiency, it is desirable to maximize the block size and number of blocks used in flow control, while minimizing the number of flow control cycles.

[0230] In such Figure 14 When flow control is performed without using inter-block wait time, as exemplified in the example, the number of blocks required for flow control needs only to be set to 1. With this configuration, flow control can be performed each time the receiving device receives data corresponding to the receive buffer size. With this configuration, P2P burst communication can be performed using flow control even when the time required to process the return of received data at the receiving device varies, that is, even when an inter-block wait time cannot be defined.

[0231] The inter-block waiting time can be used without performing flow control. In this case, for example, it is only necessary to make the number of blocks until flow control ∞ (in the communication rule, for convenience, it is only necessary to set the number of blocks to 0). In this case, Figure 12 Step S504, Figure 13 Step S603, Figure 15 Step S703 and Figure 16In the conditional branch (determination) in step S804, it is always determined that the reception of data corresponding to the number of blocks up to flow control is not completed.

[0232] exist Figure 12 Step S505 or Figure 16 In step S805, when it becomes necessary to perform processing other than communication although processing related to inter-block latency is normally performed, the signal level of the signal line CS is set to Lo. In this case, Figure 13 Step S604 or Figure 15 In step S704, when the Lo signal level of the signal line CS is detected even though the transmitting device is normally on standby for the inter-block waiting time, the transmitting device switches to the process related to flow control. With this configuration, when it becomes necessary to perform a process other than communication at the timing of the process related to the inter-block waiting time, time for the process other than communication can be secured.

[0233] In this exemplary embodiment, the communication sub-device can perform reception in broadcast communication while receiving a control signal (standby request signal) indicating a standby request after data transmission in the P2P communication method (while the signal level of the signal line CS is set to the Lo level). Specifically, Figure 10A and Figure 10B Steps S404 and S415, Figure 13 Step S609 and Figure 16 In step S808, the communication sub-device allows data to be received from the signal line DATA in the broadcast communication. Then, Figure 10A and 10B Steps S407 and S418, Figure 13 Step S611 and Figure 16 In step S813, it is determined whether data is received while data reception is allowed. In the case of receiving data, Figure 10B Step S420, Figure 13 Step S613 and Figure 16 In step S815, the P2P communication is interrupted and the communication method can be switched to the broadcast communication method. In this way, when the camera microcomputer 205 detects (recognizes) an abnormality in the communication with the adapter microcomputer 302 or the lens microcomputer 111, even if communication is performed in P2P burst communication, the camera microcomputer 205 can switch to broadcast communication. Thereafter, the camera microcomputer 205 can resume P2P burst communication via broadcast communication.

[0234] Will refer to Figure 17 A case where broadcast communication is started from the lens microcomputer 111 or the adapter microcomputer 302 serving as a communication sub-device is described. Figure 17 is a diagram illustrating signal waveforms in broadcast communication. The initiation of broadcast communication by a communication sub-device is referred to as a communication request. While communication from the camera microcomputer 205, serving as the communication master, to a communication sub-device is suspended, the communication sub-device can voluntarily restart broadcast communication by issuing a communication request to the camera microcomputer 205. As an example, a description will be given of a case where the lens microcomputer 111 notifies the adapter microcomputer 302 of the start of broadcast communication and the adapter microcomputer 302 executes broadcast communication in response to the broadcast communication from the camera microcomputer 205.

[0235] The lens microcomputer 111 starts outputting Lo to the signal line CS to notify the camera microcomputer 205 and the adapter microcomputer 302 of the start of broadcast communication. When the camera microcomputer 205 detects that the signal level of the signal line CS is set to the Lo level, the camera microcomputer 205 starts outputting Lo to the signal line CS. At this time, the lens microcomputer 111 has already started outputting Lo to the signal line CS, and therefore, the signal level of the signal line CS does not change.

[0236] The camera microcomputer 205 then outputs the data to be transmitted to the signal line DATA. In contrast, the adapter microcomputer 302 starts outputting data to the Lo line of the signal line CS at the timing of detecting the start bit ST input from the signal line DATA. At this time, the lens microcomputer 111 or the camera microcomputer 205 has already started outputting data to the Lo line of the signal line CS, so the signal level of the signal line CS does not change.

[0237] After the camera microcomputer 205 finishes transmitting data up to the stop bit SP, it cancels the Lo output to the signal line CS. In contrast, after the lens microcomputer 111 and the adapter microcomputer 302 complete receiving data input through the signal line DATA up to the stop bit SP, they analyze the received data and perform internal processing associated with the data. Thereafter, the lens microcomputer 111 and the adapter microcomputer 302 make arrangements for data reception and then cancel the Lo output to the signal line CS. As described above, by all of the camera microcomputer 205, the lens microcomputer 111, and the adapter microcomputer 302 canceling the Lo output to the signal line CS, the signal level of the signal line CS is set to Hi. Therefore, by confirming that the signal level of the signal line CS is set to Hi, it can be determined that all microcomputers have completed processing related to the current communication and made arrangements for the next communication.

[0238] After the adapter microcomputer 302 confirms that the signal level of the signal line CS is set to Hi, it starts outputting to Lo on the signal line CS to notify the camera microcomputer 205 and the lens microcomputer 111 that broadcast communication will begin. The adapter microcomputer 302 then outputs the data to be transmitted to the signal line DATA. In contrast, when the camera microcomputer 205 and the lens microcomputer 111 detect the start bit ST input from the signal line DATA, they start outputting to Lo on the signal line CS. At this point, the adapter microcomputer 302 has already started outputting to Lo on the signal line CS, so the signal level of the signal line CS does not change.

[0239] After the adapter microcomputer 302 finishes outputting data up to the stop bit SP, the adapter microcomputer 302 cancels the Lo output to the signal line CS. In contrast, after the camera microcomputer 205 and the lens microcomputer 111 complete receiving data input from the signal line DATA up to the stop bit SP, the camera microcomputer 205 and the lens microcomputer 111 analyze the received data and perform internal processing associated with the received data. The camera microcomputer 205 and the lens microcomputer 111 then make arrangements for receiving the data and cancel the Lo output to the signal line CS.

[0240] Communication using the broadcast communication method is initiated only when the camera microcomputer 205, the lens microcomputer 111, and the adapter microcomputer 302 all support the broadcast communication method. When broadcast communication is initiated from a communication sub-device, the camera microcomputer 205, acting as the communication master, cannot identify which of the lens microcomputer 111 and the adapter microcomputer 302 has set the signal level of the signal line CS to Low. Therefore, the camera microcomputer 205 must perform communication to obtain information indicating which of the lens microcomputer 111 and the adapter microcomputer 302 has initiated broadcast communication. In some cases, the timing at which the camera microcomputer 205 outputs Low to the signal line CS to initiate broadcast communication coincides with the timing at which the communication sub-device outputs Low to the signal line CS to initiate broadcast communication. In such cases, the camera microcomputer 205 cannot detect that the communication sub-device has output Low to the signal line CS, so a notification permitting the communication sub-device to initiate broadcast communication may be issued from the camera microcomputer 205 to the communication sub-device. As described above, according to this exemplary embodiment, in a system in which communication is performed using two signal lines corresponding to the signal line CS and the signal line DATA, broadcast communication can be started by the communication sub-device. With this configuration, the camera microcomputer 205 does not need to continue to frequently communicate with the lens microcomputer 111 and the adapter microcomputer 302, so unnecessary communication can be reduced.

[0241] The communication rule information regarding P2P burst communication in this exemplary embodiment includes block size, inter-block waiting time, the number of blocks until flow control, and the total size. However, the communication rule information is not limited to these. For example, in the case where flow control is performed via the signal line CS without using the inter-block waiting time, the inter-block waiting time and the number of blocks until flow control become unnecessary as communication rule information. Similarly, in the case where flow control is not performed but the inter-block waiting time is used, the number of blocks until flow control becomes unnecessary as communication rule information. These communication rule information do not need to be shared, and it is sufficient for the information corresponding to the communication rule information to be shared. For example, the number of blocks until flow control can also be the number of bytes until flow control, and the number of blocks until flow control can be obtained from the number of bytes and the block size. Similarly, the total size can be the total number of blocks, and the total size can be obtained from the total number of blocks and the block size. The communication rule information can be obtained based on information such as the ID related to the communication rule and the communication generation.

[0242] The communication rule information may include information different from the above information. For example, the communication rule information may include information such as the communication rate or the presence or absence of parity check. The communication rule information may include information such as the ID of the interchangeable lens device 100 or the camera body 200 or a command associated with the data to be acquired as information for identifying the data to be transmitted via P2P burst communication. The communication rule information may also include information for checking the reliability of the data transmitted via P2P burst communication (e.g., a checksum, a cyclic redundancy checksum (CRC), and a hash value).

[0243] Before executing P2P burst communication, communication rule information is shared between the transmitting and receiving devices through typical P2P communication. However, this configuration is not limited to this. For example, the communication rule information may be predetermined, shared between the transmitting and receiving devices using broadcast communication, or shared between the transmitting and receiving devices via other signal lines or wirelessly.

[0244] A second exemplary embodiment will be described with reference to the accompanying drawings. The second exemplary embodiment is different from the first exemplary embodiment in that flow control is performed using a signal line DATA instead of the signal line CS. Figure 18 This figure illustrates a communication waveform in P2P burst communication (communication sub-device transmission). For flow control, the camera microcomputer 205 outputs data corresponding to specific two bytes to the signal line DATA. The first byte of data corresponds to the falling edge of the signal level of the signal line CS in the first exemplary embodiment, and the second byte of data corresponds to the rising edge of the signal level of the signal line CS in the first exemplary embodiment.

[0245] Will refer to Figure 19 Details of data reception in P2P burst communication (communication sub-device transmission) to be performed by the camera microcomputer 205 are described. Figure 19 This is a diagram illustrating the processing flow of the communication master device in P2P burst communication (communication slave device transmission). Figure 12 The number of steps (processes) in the first exemplary embodiment is similar to the description of the number of steps (processes).

[0246] In step S901 , the camera microcomputer 205 operates the input-output changeover switch 2082 , and connects the signal line DATA to the data output unit of the camera microcomputer 205 .

[0247] In step S902 , the camera microcomputer 205 outputs (transmits) the first byte data.

[0248] In step S903, the camera microcomputer 205 executes the Figure 12The processing performed in step S506 is similar to the processing of the received data.

[0249] In step S904, the camera microcomputer 205 executes the Figure 12 The processing in step S509 is similar to the processing except for communication.

[0250] In step S905 , the camera microcomputer 205 outputs (transmits) the second byte data.

[0251] In step S906 , the camera microcomputer 205 operates the input-output changeover switch 2082 , and connects the signal line DATA to the data input unit of the camera microcomputer 205 .

[0252] Then, reference will be made to Figure 20 Details of the transmission process to be executed by the adapter microcomputer 302 in P2P burst communication (communication sub-device transmission) are described. Figure 20 This is a diagram illustrating the processing flow of a communication sub-device in P2P burst communication (communication sub-device transmission). Figure 13 The number of steps (processes) in the first exemplary embodiment is similar to the description of the number of steps (processes).

[0253] In step S1001 , the adapter microcomputer 302 operates the input-output changeover switch 3032 and connects the signal line DATA to the data input unit of the adapter microcomputer 302 .

[0254] In step S1002 , the adapter microcomputer 302 allows data to be received in P2P communication via the signal line DATA.

[0255] In step S1003, the adapter microcomputer 302 determines whether data transmission corresponding to the number of blocks until flow control has been completed. If data transmission has been completed ("Yes" in step S1003), the process proceeds to step S1006. If data transmission has not been completed ("No" in step S1003), the process proceeds to step S1004.

[0256] In step S1004, the adapter microcomputer 302 determines whether the first byte data has been received. If the data has been received ("Yes" in step S1004), the process proceeds to step S1007. If the data has not been received ("No" in step S1004), the process proceeds to step S1005.

[0257] In step S1005, the adapter microcomputer 302 determines whether the inter-block waiting time has elapsed. If the inter-block waiting time has elapsed ("Yes" in step S1005), the process returns to step S800. If the inter-block waiting time has not elapsed ("No" in step S1005), the process returns to step S1004.

[0258] In step S1006, similarly to step S1004, the adapter microcomputer 302 determines whether the first byte data has been received. If the first byte data has been received ("Yes" in step S1006), the process proceeds to step S1007. If the first byte data has not been received ("No" in step S1006), the process in step S1006 is repeated.

[0259] In step S1007, the adapter microcomputer 302 determines whether the second byte data has been received. If the data has been received ("Yes" in step S1007), the process proceeds to step S1008. If the data has not been received ("No" in step S1007), the process in step S1007 is repeated.

[0260] In step S1008 , the adapter microcomputer 302 operates the input-output changeover switch 3032 and connects the signal line DATA to the data output unit of the adapter microcomputer 302 .

[0261] As described above, in the present exemplary embodiment, flow control can be performed using the signal line DATA in P2P burst communication (communication sub-device transmission).

[0262] As described in the first exemplary embodiment, a notification issued via the signal line CS is also issued to a communication sub-device such as the lens microcomputer 111 that is not a communication counterpart in the P2P burst communication. Therefore, the notification may affect the operation of the communication sub-device. In contrast, in the present exemplary embodiment, flow control is performed using the signal line DATA without setting the signal line CS to Lo, so that P2P burst communication can be performed without affecting the communication sub-device. However, in this case, it is necessary to avoid a conflict in the output of the signal line DATA between the camera microcomputer 205 and the adapter microcomputer 302. Specifically, in Figure 19 Before the camera microcomputer 205 connects the signal line DATA to its data output unit in step S901, Figure 20 In step S1001, the adapter microcomputer 302 needs to connect the signal line DATA to its data input unit. In a similar manner, Figure 20Before the adapter microcomputer 302 connects the signal line DATA to its data output unit in step 1008, Figure 19 In step S906 of the camera microcomputer 205, it is necessary to connect the signal line DATA to its data input unit. Therefore, it is desirable to execute the operation in step S906 with an appropriate delay time. Figure 19 Step S901 and Figure 20 In step 1008, the signal line DATA is connected to the data output unit.

[0263] In the present exemplary embodiment, for flow control, data corresponding to specific two bytes is sent to the signal line DATA, but the configuration is not limited thereto. For example, similar to the standby request signal on the signal line CS in the case of the first exemplary embodiment, data transmission can be replaced by setting the signal level of the signal line DATA to Lo for a specific time and then setting the signal level to Hi. If there is no need to perform processing other than communication during the waiting time corresponding to the inter-block waiting time, flow control to be performed using data corresponding to two bytes can be performed using data corresponding to one byte. In other words, the first byte indicating the start of flow control among the data corresponding to the two bytes can be omitted. Specifically, the process to be performed by the adapter microcomputer 302 that performs transmission in the P2P burst communication Figure 20 It is sufficient to change the processing flow in as follows. In a case where the determination result in step S1003 becomes "No", the processing proceeds to step S1005. In a case where the determination result in step S1005 becomes "No", the processing in step S1005 is repeated. In a case where the determination result in step S1003 becomes "Yes", the processing proceeds to step S1006. In a case where the determination result in step S1006 becomes "Yes", the processing proceeds to step S1008. The conditional branch processing in step S1004 and the conditional branch processing in step S1007 are omitted. The processing performed by the camera microcomputer 205 that performs reception in P2P burst communication is omitted. Figure 19 The conditional branch processing in step S505 and Figure 19 The processing in step S902.

[0264] In addition, in the P2P burst communication performed by the communication master, the method of flow control using the signal line DATA is similar.

[0265] A third exemplary embodiment of a system, not limited to an imaging system, will be described. The system includes a transmitting device (transmitting device), a receiving device (receiving device), a first communication channel (first communication path), and a second communication channel (second communication path). The first communication channel is a channel for transmitting a signal for flow control from the receiving device to the transmitting device. The second communication channel is a channel for transmitting data from the transmitting device to the receiving device.

[0266] Figure 21 FIG is a diagram illustrating a signal waveform in burst communication using a first communication channel and a second communication channel. Figure 21 In the embodiment, after sending data corresponding to one block, the sending device stops sending data for the inter-block waiting time. When the sending of data corresponding to the number of blocks until flow control is completed, the sending device waits for flow control to be performed by the receiving device. After receiving data corresponding to one block, the receiving device makes arrangements for receiving data related to the next block within the inter-block waiting time. When the reception of data corresponding to the number of blocks until flow control is completed, the receiving device performs the necessary processing and then performs flow control. By repeating the above-mentioned processing, it becomes possible to perform efficient and high-speed data transmission from the sending device to the receiving device. In this way, the communication device that performs data communication according to this exemplary embodiment has a communication function that performs data communication in units of data blocks having a specific data size while inserting a specific waiting time. The communication device also has a standby function that performs standby processing for communication using a request signal that requests communication standby after performing communication multiple times in units of data blocks.

[0267] The above-described processing can also be applied to a system that performs flow-controlled transmission from a receiving device to a transmitting device and data transmission from the transmitting device to a receiving device using the same communication channel. Figure 22 FIG is a diagram illustrating a signal waveform in burst communication using a single communication channel. Figure 22 In the embodiment of the present invention, a transmitting device transmits data corresponding to one block while a single communication channel is connected to a data output unit, and then stops data transmission for the inter-block waiting time. When the transmission of data corresponding to the number of blocks until flow control is completed, the transmitting device connects the single communication channel to the data input unit and waits for flow control from the receiving device. The receiving device receives data corresponding to one block while a single communication channel is connected to the data input unit, and then makes arrangements for receiving data for the next block during the inter-block waiting time. When the reception of data corresponding to the number of blocks until flow control is completed, the receiving device connects the single communication channel to the data output unit, performs necessary processing, and then performs flow control. By repeating the above-mentioned process, it becomes possible to perform efficient and high-speed data transmission from the transmitting device to the receiving device.

[0268] One or more functions of the exemplary embodiments described above may also be implemented by a program for implementing these functions. The program may be supplied to a device or system via a network or storage medium and read and executed by one or more processors in a computer of the device or system. In addition, the functions may also be implemented by a circuit (e.g., an application-specific integrated circuit (ASIC)) that implements these functions.

[0269] Hereinabove, exemplary embodiments of the present invention have been described, but the present invention is not limited to these exemplary embodiments, and various modifications and changes can be made without departing from the gist thereof.

[0270] Other embodiments

[0271] The embodiment(s) of the present invention may also be implemented by a computer of a system or device that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a "non-transitory computer-readable storage medium") to perform the functions of one or more of the above-described embodiment(s) and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by a computer of the system or device, for example, by reading and executing computer-executable instructions from a storage medium to perform the functions of one or more of the above-described embodiment(s) and / or controlling one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)), and may include a network of separate computers or separate processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or storage medium. The storage medium may include, for example, a hard disk, a random access memory (RAM), a read-only memory (ROM), a storage device of a distributed computing system, an optical disk (such as a compact disk (CD), a digital versatile disk (DVD), or a Blu-ray disk (BD)). TM ), one or more of flash memory devices, memory cards, etc.

[0272] Other embodiments

[0273] The embodiments of the present invention can also be implemented by the following method, that is, providing software (program) that performs the functions of the above-mentioned embodiments to a system or device through a network or various storage media, and the computer or central processing unit (CPU) or microprocessing unit (MPU) of the system or device reads and executes the program.

[0274] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An accessory device comprising an optical member and configured to be detachably attached to an image pickup device, the accessory device comprising: a communication unit configured to perform communication with the image pickup device using a first communication performed by the image pickup device to notify the accessory device that the image pickup device is communicating with the accessory device, and a second communication and a third communication performed by the image pickup device to communicate with the accessory device that has received the notification, wherein a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the third communication is longer than a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the second communication, The communication unit is configured to perform communication using the third communication unit in units of a plurality of data blocks inserted with a specific waiting time.

2. The attachment device according to claim 1, wherein: The amount of communication information in the time interval according to the third communication is greater than the amount of communication information in the time interval according to the second communication.

3. The attachment device according to claim 1, wherein: In a case where the communication unit receives the specific command using the second communication, the communication unit is configured to perform communication with the image pickup apparatus using the third communication.

4. The attachment device according to claim 1, further comprising: a first communication path to be used for communication of a request signal; as well as a second communication path to be used for data communication between the image pickup device and the auxiliary device, Here, the communication unit is configured to perform a standby process for communication via the first communication path using the third communication use request signal.

5. The attachment device according to claim 1, further comprising: a first communication path to be used for communication of a request signal; as well as a second communication path to be used for data communication between the image pickup device and the auxiliary device, Here, the communication unit is configured to perform a standby process for communication via the second communication path using the third communication use request signal.

6. The attachment device according to claim 4, wherein: The communication unit is configured to perform standby processing in units of a plurality of data blocks using the third communication.

7. The attachment device according to claim 4, wherein: The communication unit is configured to perform communication of information on a condition of communication using the third communication using the second communication.

8. The attachment device according to claim 7, wherein: The condition of communication relates to the total size of data to be communicated, the size of a data block to be communicated, the time of a standby process, or the size of data to be communicated between two standby processes, or any combination thereof.

9. The attachment device according to claim 1, wherein: The communication unit is configured to perform data transmission from the accessory device to the image pickup device or data transmission from the image pickup device to the accessory device using the third communication.

10. An accessory device comprising an optical member and configured to be detachably attached to an image pickup device, the accessory device comprising: a communication unit configured to perform communication with the image pickup device using a first communication performed by the image pickup device to notify the accessory device that the image pickup device is communicating with the accessory device, and a second communication and a third communication performed by the image pickup device to communicate with the accessory device that has received the notification, wherein a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the third communication is longer than a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the second communication, Here, when the communication unit detects the start of communication using the first communication while performing communication using the third communication, the communication unit is configured to perform switching from communication using the third communication to communication using the first communication.

11. An image pickup device comprising an image pickup element, an accessory device being detachably attached to the image pickup device, the image pickup device comprising: a communication unit configured to perform communication with the accessory device using a first communication performed by the image pickup device to notify the accessory device that the image pickup device is communicating with the accessory device, and a second communication and a third communication used to perform communication between the image pickup device and the accessory device that has received the notification, wherein a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the third communication is longer than a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the second communication, The communication unit is configured to perform communication using the third communication unit in units of a plurality of data blocks inserted with a specific waiting time.

12. The image pickup device according to claim 11, wherein The amount of communication information in the time interval according to the third communication is greater than the amount of communication information in the time interval according to the second communication.

13. The image pickup device according to claim 11, further comprising: a first communication path to be used for communication of a request signal; as well as a second communication path to be used for data communication between the image pickup device and the auxiliary device, Here, the communication unit is configured to perform a standby process for communication via the first communication path using the third communication use request signal.

14. The image pickup device according to claim 11, further comprising: a first communication path to be used for communication of a request signal; as well as a second communication path to be used for data communication between the image pickup device and the auxiliary device, Here, the communication unit is configured to perform a standby process for communication via the second communication path using the third communication use request signal.

15. An image pickup device comprising an image pickup element, an accessory device being detachably attached to the image pickup device, the image pickup device comprising: a communication unit configured to perform communication with the accessory device using a first communication performed by the image pickup device to notify the accessory device that the image pickup device is communicating with the accessory device, and a second communication and a third communication used to perform communication between the image pickup device and the accessory device that has received the notification, wherein a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the third communication is longer than a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the second communication, Here, the communication unit is configured to start communication using the first communication while performing communication using the third communication to perform switching from communication using the third communication to communication using the first communication.

16. An image pickup system comprising: The attachment device according to claim 1; as well as An image pickup device to which the accessory device is detachably attached.

17. An image pickup system comprising: The image pickup device according to claim 11; as well as An accessory device is detachably attached to the image pickup device.

18. A computer-readable non-transitory storage medium storing a program for causing a computer to execute a communication method in an accessory device, the accessory device including an optical member and configured to be detachably attached to an image pickup device, the communication method comprising: performing communication with the image pickup apparatus using first communication for the image pickup apparatus to notify the accessory apparatus that the image pickup apparatus is communicating with the accessory apparatus, and second and third communications for performing communication between the image pickup apparatus and the accessory apparatus that has received the notification, wherein a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the third communication is longer than a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the second communication, The communication unit is configured to perform communication using the third communication unit in units of a plurality of data blocks inserted with a specific waiting time.

19. A computer-readable non-transitory storage medium storing a program for causing a computer to execute a communication method in an image pickup device, the image pickup device including an image pickup element, an accessory device being detachably attached to the image pickup device, the communication method comprising: performing communication with the accessory device using first communication, and second and third communications, the first communication being for the image pickup device to perform notification to the accessory device that the image pickup device is communicating with the accessory device, and the second and third communications being for performing communication between the image pickup device and the accessory device that has received the notification, wherein a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the third communication is longer than a time interval between two request signals requesting standby for communication between the image pickup apparatus and the accessory device using the second communication, The communication unit is configured to perform communication using the third communication unit in units of a plurality of data blocks inserted with a specific waiting time.

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