Imaging device, its control method, accessory, its control method, and storage medium

Abstract

The present invention provides a imaging device, its control method, an accessory, its control method, and a storage medium. The imaging device includes a first control unit that can communicate with the accessory by a first communication method and a second control unit that can communicate with the accessory by a second communication method. The first control unit obtains control information related to the second communication method from the accessory. The second control unit determines a control method for communicating with the accessory based on the control information obtained by the first control unit.

Description

Technical Field

[0001] The present invention relates to a photographic apparatus and accessories. Background Art

[0002] Conventionally, accessories such as a flash device and a microphone device that can be attached to and detached from a photographic apparatus have been known. The accessory performs various types of control processing in response to a command from the photographic apparatus. In order to appropriately control the accessory based on a command from the photographic apparatus, communication control suitable for each accessory (such as the type and function of the accessory) is required.

[0003] Japanese Unexamined Patent Application Publication No. 2020-12978 discloses a camera system that notifies a camera of generation information related to a communication standard supported by an accessory, notifies the accessory of generation information related to a communication standard supported by the camera, and determines a communication control method.

[0004] There is a demand for communication control that is more suitable for each accessory (such as the type and function of the accessory). Summary of the Invention

[0005] The present invention provides a photographic apparatus, an accessory, a control method for the photographic apparatus, a control method for the accessory, and a storage medium, each of which can perform communication control suitable for each accessory.

[0006] A photographic apparatus according to an aspect of the present invention is attachable to and detachable from an accessory. The photographic apparatus includes: a first control unit that can communicate with the accessory by a first communication method; and a second control unit that can communicate with the accessory by a second communication method. The first control unit acquires control information related to the second communication method from the accessory. The second control unit determines a control method for communication with the accessory based on the control information acquired by the first control unit. A control method corresponding to the above-described photographic apparatus and a storage medium storing a program that causes a computer of the photographic apparatus to execute the above-described control method also constitute another aspect of the present invention.

[0007] An accessory according to an aspect of the present invention can be attached to a camera device and can be detached from the camera device. The accessory includes a control unit that can communicate with the camera device by a first communication method and a second communication method. The control unit sends control information related to the second communication method to the camera device by the first communication method, and communicates with the camera device by the second communication method according to the control method determined by the camera device based on the control information. A control method corresponding to the above accessory, and a storage medium storing a program that causes a computer of the accessory to execute the above control method also constitute another aspect of the present invention.

[0008] A control method for a camera device that can be attached to an accessory and can be detached from the accessory, the control method including the steps of: obtaining, by a first communication method, control information related to a second communication method from the accessory; determining, based on the control information, a control method for communicating with the accessory by the second communication method; and communicating with the accessory by the second communication method according to the control method for communicating with the accessory.

[0009] A control method for an accessory that can be attached to a camera device and can be detached from the camera device, the control method including the steps of: sending, by a first communication method, control information related to a second communication method to the camera device; and communicating with the camera device by the second communication method according to the control method determined by the camera device based on the control information.

[0010] A non-transitory computer-readable storage medium storing a program for causing a computer of a camera device to execute the above control method.

[0011] A non-transitory computer-readable storage medium storing a program for causing a computer of an accessory to execute the above control method.

[0012] More features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a structural diagram of a camera system according to this embodiment.

[0014] Figure 2A is a schematic diagram of a communication waveform of SPI protocol A in this embodiment.

[0015] Figure 2B is a schematic diagram of a communication waveform of SPI protocol B in this embodiment.

[0016] Figure 2C It is a flowchart showing the operation of the camera control circuit B in SPI protocol A in this embodiment.

[0017] Figure 2D It is a flowchart showing the operation of the accessory control circuit in SPI protocol A in this embodiment.

[0018] Figure 2E It is a flowchart showing the operation of the camera control circuit B in SPI protocol B in this embodiment.

[0019] Figure 2F It is a flowchart showing the operation of the accessory control circuit in SPI protocol B in this embodiment.

[0020] Figure 3 It is an explanatory diagram of the SPI communication content in this embodiment.

[0021] Figure 4 It is an explanatory diagram of the accessory information in this embodiment.

[0022] Figure 5 It is a sequence diagram showing the operations of the camera and the accessory in this embodiment.

[0023] Figure 6 It is an explanatory diagram of the accessory type information in this embodiment.

[0024] Figure 7 It is an explanatory diagram of the factor number and factor content of the communication request in this embodiment.

[0025] Figure 8A and Figure 8B It is an explanatory diagram of the communication data interval information in the SPI communication in this embodiment.

[0026] Figure 9 It is a flowchart showing the operation of the camera control circuit A in this embodiment.

[0027] Figure 10 It is a flowchart showing the operation of the camera control circuit B in this embodiment.

[0028] Figure 11 It is a flowchart showing the operation of the accessory control circuit in this embodiment.

[0029] Figure 12A and Figure 12B Illustrates the relationship between the communication content in the SPI communication and the operation of the accessory in this embodiment.

[0030] Figure 13A and Figure 13B Illustrates an example of the I2C communication waveform in this embodiment.

[0031] Figure 14 Illustrate the processing to be performed by the camera control circuit A when transmitting N bytes of data from the camera control circuit A to the accessory control circuit in this embodiment.

[0032] Figure 15 Illustrate the processing to be performed by the camera control circuit A when the camera control circuit A receives N bytes of data from the accessory control circuit in this embodiment.

[0033] Figure 16A and Figure 16B Illustrate the processing to be performed by the accessory control circuit when communicating N bytes of data between the camera control circuit A and the accessory control circuit in this embodiment. Detailed implementation

[0034] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0035] Now refer to Figure 1 , and the camera system (imaging system) 10 according to this embodiment will be described. Figure 1 is a structural diagram of the camera system 10. The camera system 10 includes a camera (imaging device) 100 as an electronic device and an accessory 200 detachably attached to the camera 100. The camera 100 and the accessory 200 are electrically connected through one-to-one contact between a plurality of contacts (terminals) TC01 to TC21 of the camera connector 141 of the camera 100 and a plurality of contacts TA01 to TA21 of the accessory connector 211 of the accessory 200.

[0036] The camera 100 is powered by a battery 111. The battery 111 can be attached to the camera 100 and detached from the camera 100. The camera control circuit A 101 (first control unit) and the camera control circuit B 102 (second control unit) as the control units of the camera 100 are circuits that control the entire camera 100 and have a processor (microcomputer) including a CPU and the like. The camera control circuit A101 monitors switches and the like used for camera operations (not shown). The camera control circuit A 101 operates even when the camera 100 is in a standby state (low power consumption mode) and controls the system power supply and the like according to the user's operations. The camera control circuit B 102 is responsible for controlling the image sensor 122, the display circuit 127, etc., and the camera 100 stops when the camera 100 is in a standby state (low power consumption mode).

[0037] The system power supply circuit 112 is a circuit that generates the power to be supplied to each circuit in the camera 100, and includes a DC / DC converter circuit, a Low Drop Out (LDO), a charge pump circuit, etc. The 1.8V voltage generated by the system power supply circuit 112 that receives power from the battery 111 is constantly supplied as the camera microcomputer power supply VMCU_C to the camera control circuit A 101. Several types of voltages generated by the system power supply circuit 112 are supplied as the camera microcomputer power supply VMCU2_C to the camera control circuit B 102 at an arbitrary timing. The camera control circuit A 101 controls the on and off of the power supply to each circuit in the camera 100 by controlling the system power supply circuit 112.

[0038] The optical lens (lens device) 121 can be attached to and detached from the camera 100. The light from the subject incident through the optical lens 121 is imaged on an image sensor 122 such as a CMOS sensor and a CCD sensor. The optical lens 121 and the camera 100 can be integrated. The subject image formed on the image sensor 122 is encoded into a digital video signal. The image processing circuit 123 performs image processing such as noise reduction processing and white balance processing on the digital video signal to generate image data, and converts the image data into an image file in a format such as JPEG format to record the image data in the recording memory 126. The image processing circuit 123 generates VRAM image data to be displayed on the display circuit 127 from the image data. A conversion to another voltage can be used.

[0039] The memory control circuit 124 controls the transmission and reception of the image data and other data generated by the image processing circuit 123 and the like. The volatile memory 125 is a memory such as DDR3 SDRAM that can perform high-speed reading and writing, and is used as a working space for the image processing performed by the image processing circuit 123. The recording memory 126 is a readable and writable recording medium such as an SD card or a CFExpress card that can be attached to and detached from the camera 100 via a connector not shown. The display circuit 127 is a display arranged on the back surface of the camera 100, and includes an LCD panel, an organic EL display panel, etc. The backlight circuit 128 adjusts the brightness of the display circuit 127 by changing the amount of light of the backlight of the display circuit 127.

[0040] In this embodiment, the accessory power supply circuit A (hereinafter referred to as the accessory power supply circuit A) 131 and the accessory power supply circuit B (hereinafter referred to as the accessory power supply circuit B) 132 are each voltage conversion circuits that convert the voltage supplied from the system power supply circuit 112 into a predetermined voltage and generate 3.3V as the accessory power supply VACC. The accessory power supply circuit A 131 is a power supply circuit including an LDO or the like and having low self-power consumption. The accessory power supply circuit B 132 includes a DC / DC converter circuit or the like and can pass a current larger than that of the accessory power supply circuit A 131. The self-power consumption of the accessory power supply circuit B 132 is greater than that of the accessory power supply circuit A 131. Therefore, when the load current is small, the accessory power supply circuit A 131 is more efficient than the accessory power supply circuit B 132, and when the load current is large, the accessory power supply circuit B 132 is more efficient than the accessory power supply circuit A 131. The camera control circuit A 101 controls the on and off of the voltage output of the accessory power supply circuits A 131 and B 132 according to the operation state of the accessory 200.

[0041] The protection circuit 133 as a protection unit includes a current fuse element, or an electronic fuse circuit combining multiple switching elements or resistors, an amplifier, and a switching element. When the power supply current value supplied from the accessory power supply circuits A 131 and B 132 to the accessory 200 is higher than a predetermined value and becomes excessive (abnormal), the protection circuit 133 outputs an overcurrent detection signal DET_OVC. In this embodiment, the protection circuit 133 is an electronic fuse circuit, and in the case where a current of 1A or more flows, it notifies the camera control circuit A 101 of the overcurrent detection signal DET_OVC. The overcurrent detection signal DET_OVC indicates an overcurrent by becoming high level. The predetermined value may be different from 1A.

[0042] The camera connector 141 is a connector for electrically connecting to the accessory 200 via 21 contacts TC01 to TC21 arranged in a row. The contacts TC01 to TC21 are arranged in the order of contacts TC01 to TC21 from one end to the other end in this arrangement direction.

[0043] The contact TC01 is connected to the ground terminal (GND) and is used not only as a reference potential contact but also as a contact for controlling the wiring impedance of the differential signals D1N and D1P. The contact TC01 corresponds to the third ground contact. The differential signal D1N connected to the contact TC02 and the differential signal D1P connected to the contact TC03 are differential data communication signals for paired data communication and are connected to the camera control circuit B102. The contacts TC02, TC03, TC07 to TC17, TC19, and TC20 described below are communication contacts.

[0044] The contact TC04, which serves as the first ground contact, is connected to GND and serves as the reference potential contact for both the camera 100 and the accessory 200. The contact TC04 is arranged outside the contact TC05 described below in the contact arrangement direction. The accessory power supply VACC generated by the accessory power supply circuits A131 and B132 is connected to the contact TC05, which serves as the power contact, via the protection circuit 133.

[0045] The accessory attachment detection signal / ACC_DET is connected to the contact TC06, which serves as the attachment detection contact. The accessory attachment detection signal / ACC_DET is pulled up to the camera microcomputer power supply VMCU_C via the resistor element RP134 (10 kΩ). The camera control circuit A101 can detect whether the accessory 200 is attached by reading the signal level of the accessory attachment detection signal / ACC_DET. If the signal level (potential) of the accessory attachment detection signal / ACC_DET is high (predetermined potential), it is detected that the accessory 200 is not attached, and if the signal level (potential) of the accessory attachment detection signal / ACC_DET is low (GND potential as described below), it is detected that the accessory 200 is attached.

[0046] When the camera 100 is powered on, changing the signal level (potential) of the accessory attachment detection signal / ACC_DET from high level (Hi) to low level (Lo) triggers various transmissions via the contacts between the camera 100 and the accessory 200.

[0047] The camera control circuit 101 supplies power to the accessory 200 via TC05, which serves as the power contact, in response to detecting the attachment of the accessory 200.

[0048] SCLK connected to the communication contact TC07, MOSI connected to the contact TC08, MISO connected to the contact TC09, and Chip Select (CS) connected to the contact TC10 are signals used for Serial Peripheral Interface (SPI) communication in which the camera control circuit B102 becomes the communication master. In this embodiment, the SPI communication has a communication clock frequency of 1 MHz, a data length of 8 bits (1 byte), a bit order with MSB first, and a full-duplex communication method.

[0049] In this embodiment, the camera 100 and the accessory 200 can support two types of communication protocols (control methods) of the SPI communication method. The first communication protocol (first control method) is a method in which the camera 100 does not confirm whether the accessory 200 is in a communicable state (the communicable state of the accessory 200 or whether the accessory 200 is communicable) before outputting SCLK, and will be referred to as SPI protocol A in this embodiment. Figure 2A is a schematic diagram of the communication waveform of SPI protocol A. InFigure 2A In this case, the CS signal is activated low.

[0050] The camera control circuit B 102 changes CS to a low level at timing A1 and requests SPI communication from the accessory control circuit 201 (control unit). At timing A2, which is a predetermined time T_CS after timing A1, the camera control circuit B 102 starts outputting SCLK and MOSI. Similarly, when the accessory control circuit 201 detects the trailing edge of SCLK, the accessory control circuit 201 starts outputting MISO. The camera control circuit B 102 stops outputting SCLK at timing A3 when it has completed outputting 1 byte of SCLK. The camera control circuit B 102 stops outputting SCLK at timing A3 and continues for a predetermined time T_INTERVAL. After T_INTERVAL has elapsed, at timing A4, it restarts the output of SCLK and performs the next 1-byte communication.

[0051] Figure 2C is a flowchart showing the operation of the camera control circuit B 102 in SPI protocol A. In step S101, the camera control circuit B 102 stores a value representing the number of bytes to be communicated in an internal variable N. For example, 3 is stored in the case of 3-byte communication. Next, in step S102, the camera control circuit B 102 changes CS to a low level and requests SPI communication. In step S103, the camera control circuit B 102 performs a wait process until a predetermined time T_CS has elapsed after CS has been changed to a low level. After the predetermined time T_CS has elapsed, the process proceeds to step S104.

[0052] In step S104, the camera control circuit B 102 controls SCLK output, MOSI data output, and MISO data input, and performs 1-byte data communication. Next, in step S105, the camera control circuit B 102 determines whether the internal variable N representing the number of communication bytes is 0. If the internal variable N is 0, the process proceeds to step S106. On the other hand, if the internal variable N is not 0, the process proceeds to step S107.

[0053] In step S107, the camera control circuit B 102 stores the value obtained by decrementing the value of the internal variable N representing the communication byte count by 1 as the new internal variable N. Next, in step S108, the camera control circuit B 102 performs a waiting process until a predetermined time T_INTERVAL has elapsed after the completion of the 1-byte data communication in step S104. Then, after the predetermined time T_INTERVAL has elapsed, the process returns to the process of step S104, and the camera control circuit B 102 performs the same process again. In step S106, the camera control circuit B 102 changes CS to a high level and ends a series of SPI communications.

[0054] Figure 2D Illustrates the operation of the accessory control circuit 201 in SPI protocol A. In step S201, the accessory control circuit 201 determines whether CS has changed to a low level. If CS has changed to a low level, the process proceeds to step S202, and if CS has not changed to a low level, the process returns to step S211.

[0055] In step S202, the accessory control circuit 201 performs 1-byte data communication through MOSI data input control and MISO data output control in response to the input of the SCLK signal. Next, in step S203, the accessory control circuit 201 determines whether CS has changed to a high level. If CS has changed to a high level, the accessory control circuit 201 determines that the SPI communication is complete. If CS has not changed to a high level, the process returns to step S202, causing the accessory control circuit 201 to perform the next 1-byte communication.

[0056] The second communication protocol (second control method) is a method of confirming whether the accessory 200 is in a communicable state (the communicable state of the accessory 200) before the camera 100 outputs the SCLK, and will be referred to as SPI protocol B in this embodiment. Figure 2B Is a schematic diagram of the communication waveform of SPI protocol B. At timing B1, the camera control circuit B 102 changes CS to a low level and requests SPI communication from the accessory control circuit 201. The camera control circuit B 102 confirms the potential of MISO together with the communication request. If the potential of MISO is high, the camera control circuit B 102 determines that the accessory control circuit 201 is in a communicable state. On the other hand, if the potential of MISO is low, the camera control circuit B 102 determines that the accessory control circuit 201 is in a non-communicable state.

[0057] On the other hand, when the accessory control circuit 201 detects the trailing edge of CS, the accessory control circuit 201 controls to change MISO to a high level when SPI communication is available, and controls to change MISO to a low level when the communication is unavailable (B2).

[0058] When the camera control circuit B102 confirms that MISO is at a high level at timing B3, the camera control circuit B102 starts to output SCLK and MOSI. The accessory control circuit 201 starts to output MISO when detecting the trailing edge of SCLK. The camera control circuit B102 stops outputting SCLK when the output of 1 byte of SCLK is completed at timing B4.

[0059] After 1-byte communication, the accessory control circuit 201 controls to change MISO to a high level when SPI communication is available, and controls to change MISO to a low level when SPI communication is unavailable (B5, B6). The camera control circuit B102 confirms the potential of MISO at timing B7. If MISO is at a high level, it is determined that the accessory control circuit 201 is in a communicable state, and if MISO is at a low level, it is determined that the accessory control circuit 201 is in a non-communicable state.

[0060] Figure 2E It is a flowchart illustrating the processing of the camera control circuit B102 in SPI protocol B. In step S111, the camera control circuit B102 stores a value representing the number of bytes to be communicated in an internal variable N. For example, 3 is stored in the case of 3-byte communication. Next, in step S112, the camera control circuit B102 changes CS to a low level and requests SPI communication. Next, in step S113, the camera control circuit B102 determines whether MISO changes to a high level. If MISO is at a high level, the process proceeds to step S114, and if MISO is not yet at a high level, the process returns to step S113.

[0061] In step S114, the camera control circuit B102 controls SCLK output, MOSI data output, and MISO data input to perform 1-byte data communication. Next, in step S115, the camera control circuit B102 determines whether the internal variable N representing the number of communication bytes is 0. If the internal variable N is 0, the process proceeds to step S116, and if the internal variable N is not 0, the process proceeds to step S117.

[0062] In step S117, the camera control circuit B 102 stores the value obtained by decrementing the value of the internal variable N representing the number of communication bytes by 1 as the new internal variable N. Next, in step S118, the camera control circuit B 102 determines whether MISO changes to a high level. If MISO is at a high level, the process proceeds to step S114, and if MISO is not at a high level, the process returns to step S118. In step S116, the camera control circuit B 102 changes CS to a high level and ends a series of SPI communications.

[0063] Figure 2F is a flowchart illustrating the operation of the accessory control circuit 201 in SPI protocol B. In step S211, the accessory control circuit 201 determines whether CS changes to a low level. If CS changes to a low level, the process proceeds to step S212, and if CS has not changed to a low level, the process returns to step S211.

[0064] In step S212, the accessory control circuit 201 determines whether SPI communication is available. If SPI communication is available, the process proceeds to step S213, and if SPI communication is not available, the process proceeds to step S214. In step S213, the accessory control circuit 201 performs control to change MISO to a high level, and the process proceeds to step S215. In step S214, the accessory control circuit 201 performs control to change MISO to a low level, and the process returns to step S212.

[0065] In step S215, the accessory control circuit 201 controls MOSI data input and MISO data output in response to the input of the SCLK signal and performs 1-byte data communication. Next, in step S216, the accessory control circuit 201 determines whether CS changes to a high level. If CS changes to a high level, it is determined that the SPI communication is completed, and if CS does not change to a high level, the process returns to step S212 for the next 1-byte communication.

[0066] Figure 3 Describes the communication content when notifying an operation execution instruction (command) from the camera 100 to the accessory 200 through SPI communication in this embodiment. The camera control circuit B 102 sends the information CMD representing the command number as MOSI data to the accessory control circuit 201 in the first-byte communication. The accessory control circuit 201 sends the value 0xA5 as the MISO data, which is the information representing the communicable state. In the case where the first-byte communication process cannot be executed, the accessory control circuit 201 sends a value other than 0xA5 as the MISO data.

[0067] The camera control circuit B 102 transmits the argument MOSI_DATA1 corresponding to the command number CMD in the second-byte communication. From the third byte to the (N - 2)th byte, the camera control circuit B 102 similarly transmits the arguments MOSI_DATA2 to MOSI_DATA[N - 3] corresponding to the command number CMD.

[0068] The accessory control circuit 201 transmits the command number CMD received in the first byte as MISO data to the camera control circuit B 102 in the second-byte communication. This configuration enables the camera control circuit B 102 to determine that the accessory control circuit 201 has correctly received the MOSI data.

[0069] The accessory control circuit 201 transmits the return value MISO_DATA1 corresponding to the command number CMD as MISO data in the third-byte communication. From the fourth byte to the (N - 2)th byte, the accessory control circuit 201 similarly transmits the return values MISO_DATA2 to MISO_DATA[N - 4] corresponding to the command number CMD. It is assumed that the number of arguments and the number of return values are predetermined for each command number. Either one or both of the arguments and the return values can be omitted.

[0070] The camera control circuit B 102 transmits the checksum data CheckSum_C as MOSI data to the accessory control circuit 201 in the (N - 1)th byte communication. The checksum data CheckSum_C is a value calculated by the following expression (1).

[0071] CheckSum_C = EXOR(AND(SUM(CMD, MOSI_DATA1, …, MOSI_DATA[N - 3]), 0xFF), 0xFF) (1)

[0072] The accessory control circuit 201 transmits 0x00 as MISO data.

[0073] The camera control circuit B 102 transmits 0x00 as MOSI data in the Nth byte communication. The accessory control circuit 201 transmits the checksum data CheckSum_A as MISO data. The checksum data CheckSum_A is calculated by the following expressions (2) and (3).

[0074] When the value of CheckSum_C received by the camera control circuit B 102 in the (N - 1)th byte communication is consistent with the value of CheckSum_C calculated by the camera control circuit B 102, CheckSum_A is calculated by expression (2).

[0075] CheckSum_A = EXOR(AND(SUM(0xA5, CMD, MIS0_DATA1, …, MOSI_DATA[N - 4]), 0xFF), 0xFF)(2)

[0076] When the value of CheckSum_C received by the camera control circuit B 102 in the (N - 1)-th byte communication is inconsistent with the value of CheckSum_C calculated by the camera control circuit B 102, CheckSum_A is calculated by expression (3).

[0077] CheckSum_A = AND(SUM(0xA5, CMD, MIS0_DATA1, …, MOSI_DATA[N - 4]), 0xFF)(3)

[0078] The contact TC11 is connected to the communication request signal / WAKE for requesting communication from the accessory 200 to the camera control circuit A 101. The communication request signal / WAKE is pulled up to the camera microcomputer power supply VMCU_C via a resistor. The camera control circuit A 101 can receive a communication request from the accessory 200 by detecting the trailing edge of the communication request signal / WAKE.

[0079] SDA connected to the contact TC12 and SCL connected to the contact TC13 are signals for inter-integrated circuit (I2C) communication in which the camera control circuit A 101 is the communication master. SDA and SCL are open-drain communications pulled up by the camera microcomputer power supply VMCU_C and have a communication frequency of 100 kbps in this embodiment. In I2C communication, both data transmission from the camera 100 and data transmission from the accessory 200 are performed via SDA. The communication speed of I2C communication is lower than that of SPI communication. The communication speed of SPI communication is higher than that of I2C communication, so it is suitable for information communication with a large amount of data. Therefore, in the communication between the camera 100 and the accessory 200 in this embodiment, information with a large amount of data is communicated by using SPI communication, and information with a small amount of data is communicated by using I2C communication. For example, data is first communicated by using I2C communication, and when SPI communication is available or needed based on this data, control can be performed to further execute SPI communication.

[0080] Figure 13A and Figure 13B An example of the I2C communication waveform is illustrated. Figure 13A An example of the waveform is illustrated when the camera sends N-byte data (DATA[1] to DATA[N]) to the accessory, and Figure 13BIllustrate a waveform example when the camera receives N - byte data (DATA[1] to DATA[N]) from the accessory. In Figure 13A and Figure 13B the upper waveform illustrates SCL, and the lower waveform illustrates SDA.

[0081] Below the SDA waveform, the meaning of the signal at each timing and the control circuit for controlling the output level of the SDA signal are illustrated, whether it is the camera control circuit A 101 or the accessory control circuit 201. The communication data includes data in 1 - byte units and 1 - bit information indicating a response. The upper part of each figure illustrates the number of bytes of data from the start of communication for easy explanation. Since the details of the communication content will be described with reference to Figures 14 to 16A and Figure 16B therefore, the overview will be described with reference to Figure 13A and Figure 13B

[0082] In Figure 13A in the first - byte communication and the second - byte communication, the camera control circuit A101 notifies the accessory control circuit 201 of the storage address information related to the data to be sent. In the third - byte communication to the (N + 2)-th byte communication, the camera control circuit A101 sends N - byte data (DATA[address] to DATA[address + N]) to the accessory control circuit 201.

[0083] In Figure 13B in the first - byte communication and the second - byte communication, the camera control circuit A 101 notifies the accessory control circuit 201 of the storage address information related to the data to be received. In the third - byte communication to the (N + 3)-th byte communication, the camera control circuit A 101 receives N - byte data (DATA[address] to DATA[address + N]) from the accessory control circuit 201.

[0084] Next, the flowcharts of Figures 14 to 16A and Figure 16B will be described. Figure 14 The flowchart in

[0085] illustrates the processing to be performed by the camera control circuit A 101 when the camera control circuit A 101 sends N - byte data to the accessory control circuit 201. In step S3001, the camera control circuit A 101 stores the value representing the number of bytes to be sent in the internal variable N. For example, when sending 3 bytes, 3 is stored. In this embodiment, 3 is stored.

[0086] ​In step S3002, the camera control circuit A 101 changes SDA to low level during the period when SCL is at high level (START condition). Thereby, the start of communication is notified to the accessory control circuit 201.

[0087] In step S3003, the camera control circuit A 101 sets the slave address information indicating the slave address of the accessory control circuit 201 to the high 7 bits of the data to be transmitted. In this embodiment, it is assumed that the slave address of the accessory control circuit 201 is 1010000 in binary.

[0088] In step S3004, the camera control circuit A 101 sets the information indicating write communication to the lowermost 1 bit of the data to be transmitted. Setting this bit to 0 means write communication.

[0089] In step S3005, the camera control circuit A 101 transmits the data set as the data to be transmitted in steps S3003 and S3004 to the accessory control circuit 201 (10100000 in binary and 0xA0 in hexadecimal).

[0090] In step S3006, after transmitting 1-byte data, the camera control circuit A 101 outputs SCL and maintains it for one clock, and confirms the signal level of SDA. When the signal level of SDA is low, it is determined as the data reception notification (ACK) from the accessory control circuit 201, and the process proceeds to step S3007. On the other hand, when the signal level of SDA is high, it is determined that the accessory control circuit 201 has not normally received the data, and the process proceeds to step S3014.

[0091] In step S3007, the camera control circuit A 101 sets the storage address information (start address information) of the data to be transmitted to the accessory control circuit 201 to the data to be transmitted. In this embodiment, the size of the start address information is 1 byte, and the value is 0x00.

[0092] In step S3008, the camera control circuit A 101 transmits the set 1-byte start address information (value 0x00) to the accessory control circuit 201.

[0093] In step S3009, after the camera control circuit A 101 sends 1-byte start address information data, it outputs SCL and holds it for one clock, and confirms the signal level of SDA. When the signal level of SDA is low, it is determined as a data reception notification (ACK) from the accessory control circuit 201, and the process proceeds to step S3010. On the other hand, when the signal level of SDA is high, it is determined that the accessory control circuit 201 has not received the data normally, and the process proceeds to step S3014.

[0094] In step S3010, the camera control circuit A 101 stores 1 in the internal variable M. The internal variable M is a variable used to count the number of data to be sent.

[0095] In step S3011, the camera control circuit A 101 outputs 1-byte data to the accessory control circuit 201 by outputting 1-byte SCL and changing SDA to the desired signal level during the period when SCL is at a low level. Here, the start address information is 0x00 and the internal variable M is 1, so 1-byte data corresponding to the address 0x00 is sent.

[0096] In step S3012, after the camera control circuit A 101 sends 1-byte data, it outputs SCL and holds it for one clock, and confirms the signal level of SDA. When the signal level of SDA is low, it is determined as a data reception notification (ACK) from the accessory control circuit 201, and the process proceeds to step S3013. On the other hand, when the signal level of SDA is high, it is determined that the accessory control circuit 201 has not received the data normally, and the process proceeds to step S3014.

[0097] In step S3013, the camera control circuit A 101 confirms whether the internal variable M has the same value as the internal variable N. When the internal variable M has the same value as the internal variable N, it is determined that the transmission of all data is completed, and the process proceeds to step S3014. When the internal variable M does not have the same value as the value of the internal variable N, it is determined that there is still data to be sent, and the process proceeds to step S3015.

[0098] In step S3015, the camera control circuit A 101 adds 1 to the internal variable M, and the process returns to step S3011.

[0099] Therefore, after the process returns to step S3011, the camera control circuit A 101 sequentially increments the address of the data to be transmitted and transmits 1-byte data corresponding to each address. In this way, the camera control circuit A 101 transmits N-byte data to the accessory control circuit 201 by repeatedly transmitting 1-byte data until the internal variable M and the internal variable N have the same value in the process of step S3013. When the internal variable N is set to 3 as in this embodiment, 3-byte data can be transmitted.

[0100] In step S3014, the camera control circuit A101 changes SDA to high level (stop (STOP) condition) while SCL is at high level. Thereby, the communication end is notified to the accessory control circuit 201.

[0101] Figure 15 The flowchart in shows the processing to be performed by the camera control circuit A 101 when the camera control circuit A 101 receives N-byte data from the accessory control circuit 201.

[0102] In step S3101, the camera control circuit A 101 stores the numerical value indicating the number of bytes to be received in the internal variable N. For example, when 3-byte data is received, 3 is stored. In this embodiment, 3 is stored.

[0103] In steps S3102 to S3106, the camera control circuit A 101 performs the same processing as steps S3002 to S3006 respectively, so the description thereof will be omitted.

[0104] In step S3107, the camera control circuit A 101 sets the storage address information (start address information) of the data received from the accessory control circuit 201 to the transmitted data. In this embodiment, the size of the start address information is 1 byte and the value is 0x00.

[0105] In step S3108, the camera control circuit A 101 transmits the set 1-byte start address information (value 0x00) to the accessory control circuit 201.

[0106] In step S3109, after transmitting the 1-byte start address information data, the camera control circuit A 101 outputs SCL and maintains it for one clock, and confirms the signal level of SDA. When the signal level of SDA is low, it is determined as the data reception notification (ACK) from the accessory control circuit 201, and the process proceeds to step S3110. On the other hand, when the signal level of SDA is high, it is determined that the accessory control circuit 201 has not normally received the data, and the process proceeds to step S3122.

[0107] In step S3110, similar to step S3102, the camera control circuit A 101 changes SDA to low during the period when SCL is high, and notifies the accessory control circuit 201 of the start condition.

[0108] In step S3111, the camera control circuit A 101 sets the slave address information representing the slave address of the accessory control circuit 201 to the high 7 bits of the data to be transmitted. In this embodiment, it is assumed that the slave address of the accessory control circuit 201 is 1010000 in binary.

[0109] In step S3112, the camera control circuit A 101 sets the information indicating read communication to the lowermost 1 bit of the data to be transmitted. Setting this bit to 1 means read communication.

[0110] In step S3113, the camera control circuit A 101 transmits the data set as the data to be transmitted in steps S3003 and S3004 (10100001 in binary and 0xA1 in hexadecimal) to the accessory control circuit 201.

[0111] In step S3114, after transmitting 1-byte data, the camera control circuit A 101 outputs SCL and maintains it for one clock, and confirms the signal level of SDA. When the signal level of SDA is low, it is determined as the data reception notification (ACK) from the accessory control circuit 201, and the process proceeds to step S3115. On the other hand, when the signal level of SDA is high, it is determined that the accessory control circuit 201 has not normally received the data, and the process proceeds to step S3122.

[0112] In step S3115, the camera control circuit A 101 stores 1 in the internal variable M. The internal variable M is a variable for counting the number of received data.

[0113] In step S3116, the camera control circuit A 101 outputs 1-byte SCL and reads the signal level of SDA at the timing when SCL changes from low level to high level. This configuration enables receiving 1-byte data from the accessory control circuit 201. The received 1-byte data can be stored in the volatile memory 125 corresponding to the address 0x00 or used for predetermined processing.

[0114] In step S3117, the camera control circuit A 101 determines whether 1-byte data has been normally received. If it has been normally received, the process proceeds to step S3118. If it has not been normally received, the process proceeds to step S3119.

[0115] In step S3118, the camera control circuit A 101 confirms whether the internal variable M has the same value as the value of the internal variable N. If the internal variable M has the same value as the value of the internal variable N, it is determined that the reception of all data is completed, and the process proceeds to step S3119. If the internal variable M does not have the same value as the value of the internal variable N, it is determined that there is still data to be received, and the process proceeds to step S3120.

[0116] In step S3120, the camera control circuit A 101 provides a data reception notification (ACK) to the accessory control circuit 201, and notifies the accessory control circuit 201 of continuous data communication by outputting 1-byte SCL and by performing control to change SDA to a low level.

[0117] In step S3121, the camera control circuit A 101 adds 1 to the internal variable M, and the process returns to step S3116.

[0118] Therefore, after the process returns to step S3116, the camera control circuit A 101 sequentially increments the address of the data to be received, and receives 1-byte data corresponding to each address. In this way, the camera control circuit A 101 receives N-byte data from the accessory control circuit 201 by repeating the reception of 1-byte data until the internal variable M and the internal variable N have the same value in the process of step S3118. In the case where the internal variable N is set to 3 as in this embodiment, 3-byte data can be received.

[0119] In step S3119, the camera control circuit A 101 outputs 1-byte SCL, and performs control to change SDA to a high level to notify the accessory control circuit 201 of the completion of data communication (NACK).

[0120] In step S3122, the camera control circuit A 101 changes SDA to a high level (stop condition) while SCL is at a high level. Thereby, the accessory control circuit 201 is notified of the end of communication.

[0121] Figure 16A and Figure 16B Illustrates the processing to be performed by the accessory control circuit 201 when the camera control circuit A 101 sends N-byte data to the accessory control circuit 201 and when the camera control circuit A 101 receives N-byte data from the accessory control circuit 201.

[0122] In step S3201, the accessory control circuit 201 waits for SDA to change to a low level (start condition) while SCL is at a high level. When the accessory control circuit 201 detects the start condition, the process proceeds to step S3202.

[0123] In step S3202, the accessory control circuit 201 stores 0 in the internal variable M. The internal variable M is a variable used to count the number of transmitted data and the number of received data.

[0124] In step S3203, the accessory control circuit 201 receives 1-byte data sent from the camera control circuit A101.

[0125] In step S3204, the accessory control circuit 201 determines whether the high 7-bit data of the 1-byte data received in step S3203 is consistent with the slave address of the accessory control circuit 201 (0x50 in this embodiment). If the address is consistent with the slave address of the accessory control circuit 201, the process proceeds to step S3205. If the address is not consistent with the slave address of the accessory control circuit 201, the process proceeds to step S3221.

[0126] In step S3205, the accessory control circuit 201 provides a data reception notification (ACK) to the camera control circuit A 101 by controlling the SDA to be changed to a low level for the next SCL clock output after receiving the 1-byte data.

[0127] In step S3206, the accessory control circuit 201 determines the type of data for the next 1-byte communication based on the low 1-bit data of the 1-byte data received in step S3203. If the low 1-bit data is 0, it is determined that the data for the next 1-byte communication is the start address information from the camera control circuit A 101 to the accessory control circuit 201, and the process proceeds to step S3207. If the low 1-bit data is 1, it is determined that the data for the next 1-byte communication is the data sent from the accessory control circuit 201 to the camera control circuit A101, and the process proceeds to step S3209.

[0128] In step S3207, the accessory control circuit 201 receives 1-byte data sent from the camera control circuit A101. The received 1-byte data is information indicating the address of the data to be transmitted and received in the subsequent communication. In this embodiment, as referred to in Figure 14 and Figure 15 it is assumed that the start address information is 0x00.

[0129] On the other hand, in step S3209, the accessory control circuit 201 uses the address information pre-stored in the accessory control circuit 201 or the address information notified in advance from the camera control circuit A 101 as the start address information.

[0130] In step S3208, when the accessory control circuit 201 determines that 1-byte data can be normally received, the process proceeds to step S3210. When it is determined that 1-byte data cannot be normally received, the process proceeds to step S3221.

[0131] In step S3210, the accessory control circuit 201 provides a data reception notification (ACK) to the camera control circuit A 101 by controlling to change SDA to a low level for the next SCL clock output after receiving 1-byte data.

[0132] In step S3211, the accessory control circuit 201 confirms whether SDA changes to a low level (start condition) while SCL is at a high level. When the accessory control circuit 201 detects the start condition, the accessory control circuit 201 determines that the 1-byte data to be communicated next is data representing the slave device address and communication type to be sent from the camera control circuit A101 to the accessory control circuit 201. Then, the process proceeds to step S3212. When the accessory control circuit 201 does not detect the start condition, the accessory control circuit 201 determines that the 1-byte data to be communicated next is the data information received by the accessory control circuit 201 from the camera control circuit A 101. Then, the process proceeds to step S3216.

[0133] In step S3212, the accessory control circuit 201 receives 1-byte data sent from the camera control circuit A 101.

[0134] In step S3213, the accessory control circuit 201 determines whether the high 7-bit data of the 1-byte data received in step S3212 is consistent with the slave device address of the accessory control circuit 201 (0x50 in this embodiment). When the high 7-bit data is consistent with the slave device address of the accessory control circuit 201, the process proceeds to step S3214. When the high 7-bit data is not consistent with the slave device address of the accessory control circuit 201, the process proceeds to step S3221.

[0135] In step S3214, the accessory control circuit 201 determines the data type for the next 1-byte communication based on the low 1-bit data of the 1-byte data received in step S3203. When the low 1-bit data is 0, the process proceeds to step S3221. When the low 1-bit data is 1, it is determined that the data for the next 1-byte communication is data to be sent from the accessory control circuit 201 to the camera control circuit A101, and the process proceeds to step S3215.

[0136] In step S3215, the accessory control circuit 201 provides a data reception notification (ACK) to the camera control circuit A101 by controlling to change SDA to a low level for the next SCL clock output after receiving 1-byte data.

[0137] In step S3222, the accessory control circuit 201 sends 1-byte data corresponding to the start address information received from the camera control circuit A101 in step S3207 or the start address information determined in step S3209 to the camera control circuit A101.

[0138] In step S3223, the accessory control circuit 201 adds 1 to the internal variable M, and the process proceeds to step S3224.

[0139] In step S3224, after sending 1-byte data, the accessory control circuit 201 confirms the signal level of SDA. When the signal level of SDA is high, the camera control circuit A101 determines that this is a notification (NACK) of receiving all data, and the process proceeds to step S3225. On the other hand, when the signal level of SDA is low, it is determined that the camera control circuit A101 continues to request data transmission from the accessory control circuit 201, and the process returns to step S3222. Therefore, after the process returns to step S3222, the accessory control circuit 201 sequentially increments the address of the data to be sent and sends 1-byte data corresponding to each address. Thus, by repeatedly sending 1-byte data from the camera control circuit A101 until NACK is notified in the process of step S3224, the accessory control circuit 201 sends N-byte data to the camera control circuit A101.

[0140] In step S3225, the accessory control circuit 201 waits for a stop condition in which SDA changes to a high level while SCL is at a high level. When the accessory control circuit 201 detects the stop condition, the communication is terminated.

[0141] On the other hand, in step S3216, the accessory control circuit 201 receives 1-byte data and stores the 1-byte data as data corresponding to the start address information received from the camera control circuit A101 in step S3207 in a non-volatile memory (not shown), or uses the 1-byte data for a predetermined process.

[0142] In step S3217, the accessory control circuit 201 adds 1 to the internal variable M, and the process proceeds to step S3218.

[0143] In step S3218, if the accessory control circuit 201 determines that 1-byte data can be normally received, the process proceeds to step S3219. If it is determined that 1-byte data cannot be normally received, the process proceeds to step S3221.

[0144] In step S3219, the accessory control circuit 201 provides a data reception notification (ACK) to the camera control circuit A101 by controlling to change SDA to a low level for the next SCL clock output after receiving 1-byte data.

[0145] In step S3230, the accessory control circuit 201 confirms whether SDA changes to a high level (stop (STOP) condition) while SCL is at a high level. When the accessory control circuit 201 detects a stop condition, the accessory control circuit 201 terminates the communication. On the other hand, when the accessory control circuit 201 does not detect a stop condition, the accessory control circuit 201 determines that data will be continuously transmitted from the camera control circuit A101 to the accessory control circuit 201. Then, the process returns to step S3216.

[0146] Therefore, after the process returns to step S3216, the accessory control circuit 201 sequentially increments the address of the data to be received and receives 1-byte data corresponding to each address. By repeating the reception of 1-byte data until a stop condition is notified in step S3220, the accessory control circuit 201 receives N-byte data from the camera control circuit A101.

[0147] Figure 4 Describe the accessory information that the accessory 200 has in a non-volatile memory (not shown). As Figure 4 shown, the accessory information is mapped in the memory space at addresses 0x00 to 0x0F, and the accessory information can be read out from the accessory 200 through I2C communication. In the I2C communication according to the present embodiment, a checksum value for the read data is added as the final data of the communication. Details of the accessory information will be described below.

[0148] The FNC1 signal connected to the contact TC14, the FNC2 signal connected to the contact TC15, the FNC3 signal connected to the contact TC16, and the FNC4 signal connected to the contact TC17 are function signals whose functions are variable according to the type of the attached accessory 200. For example, when the accessory 200 is a microphone device, the signal communicated via TC15 is a voice data signal, and when the accessory 200 is a lighting device (flash device), the signal communicated via TC14 is a signal notifying the light emission timing.

[0149] Signals for implementing different functions can be communicated via the same contacts according to the type of the attached accessory. For example, when the accessory 200 is an accessory other than the lighting device, a synchronization signal for controlling a timing different from the light emission timing can be communicated via TC14. TC14 to TC17 correspond to the function signal contacts. Communication using at least one of the function signal contacts will also be referred to as function signal communication.

[0150] Function signal communication can be performed at a timing independent of I2C communication and SPI communication in parallel with I2C communication and SPI communication.

[0151] As used herein, the accessory type means the above-described microphone device, lighting device, etc. Accessories that achieve the same purpose (such as lighting with different performances) belong to the same type of accessories. Accessories that achieve different purposes (such as a microphone device and a lighting device) are different types of accessories.

[0152] Function signal communication is performed based on the information obtained through I2C communication or SPI communication.

[0153] The contact TC18 as the second ground contact is also connected to GND, and similar to the contact TC04, is a contact used as the reference potential for the camera 100 and the accessory 200. The differential signal D2N connected to the contact TC19 and the differential signal D2P connected to the contact TC20 are data communication signals for performing data communication in pairs, and are connected to the camera control circuit B102. For example, USB communication can be performed via TC19 and TC20. The contact TC21 is connected to GND, and can be used not only as a reference potential contact but also as a contact for controlling the wiring impedance of the differential signals D2N and D2P. The contact TC21 corresponds to the fourth ground contact.

[0154] The contacts TC01, TC04, TC06, TC18, and TC21 are connected to the GND portion of, for example, a flexible printed circuit (FPC) board, and the GND portion of the FPC board is fixed to a metal member serving as the GND level of the camera 100 by screws or the like. The metal member serving as the GND level includes, for example, an engagement member that can be engaged with the accessory 200 in the accessory socket portion, and a bottom plate (not shown) inside the camera 100.

[0155] In the present embodiment, the attachment detection contact TC06 to which the accessory attachment detection signal / ACC_DET is connected is arranged adjacent to the contact (first clock contact) TC07 that transmits the transmission clock signal SCLK (first clock signal). Generally, noise (clock noise) associated with potential fluctuations of the clock signal is transmitted to contacts adjacent to the contact of the clock signal, which may cause malfunctions. In particular, as in the present embodiment, this effect is significant in a configuration having many contacts with a short distance between the contacts. Therefore, by arranging the attachment detection contact TC06 adjacent to the SCLK contact TC07, the influence of clock noise can be suppressed.

[0156] The accessory attachment detection signal / ACC_DET is pulled up before the accessory is attached, but is set to the GND potential after the accessory is attached. On the other hand, before the accessory is attached, since the SCLK contact TC07 for transmitting the clock signal does not transmit the clock signal, the potential does not fluctuate. Only after the accessory is attached does the potential fluctuate due to the transmission of the clock signal.

[0157] When the SCLK contact TC07 transmits the clock signal, the attachment detection contact TC06 is at the GND potential. Therefore, even if the attachment detection contact TC06 receives clock noise, the potential of the control circuits of the camera 100 and the accessory 200 is unlikely to fluctuate, thereby preventing malfunctions. In addition, the clock noise can be suppressed from being transmitted to a position farther than the accessory detection contact TC06. As a result, it is not necessary to provide a GND terminal, and thus the influence of clock noise can be suppressed without increasing the number of contacts.

[0158] SCL (second clock signal) as the clock signal is also transmitted to the contact (second clock contact) TC13. However, the SCLK transmitted to the SCLK contact TC07 has a higher frequency than that of SCL, and the SCLK contact TC07 generates more clock noise than the SCL contact TC13. Therefore, arranging the attachment detection contact TC06 adjacent to the SCLK contact TC07 rather than adjacent to the SCL contact TC13 is more effective in preventing malfunctions caused by clock noise.

[0159] Except for the difference in frequency, the SCL sent by the SCL contact TC13 is the clock signal of the I2C communication standard, and the voltage fluctuation of the signal line is driven by an open-drain connection. On the other hand, the SCLK sent by the SCLK contact TC07 is the clock signal of the SPI communication standard, and the voltage fluctuation of the signal line is driven by a CMOS output. Therefore, compared with the edge of the voltage fluctuation of the SCLK contact TC07, the edge of the voltage fluctuation of the SCL contact TC13 tends to be smoother and clock noise is less likely to occur. Therefore, arranging the attachment detection contact TC06 next to the SCLK contact TC07 rather than next to the SCL contact TC13 is more effective in preventing failures caused by clock noise.

[0160] The differential signals D1N and D1P can be sent in pairs to the first differential signal contact TC19 and the second differential signal contact TC20 to send a clock signal. In this case, a clock signal (third clock signal) with a frequency higher than the frequencies of the SCLK contact TC07 and the SCL contact TC13 can be sent. However, since the differential signals D1N and D1P are paired signals, the clock noise emission is smaller than that of the SCLK contact TC07 and the SCL contact TC13 that send single-ended signals. Therefore, it is more effective to prevent failures caused by clock noise by arranging the attachment detection contact TC06 next to the SCLK contact TC07 rather than next to the first differential signal contact TC19 and the second differential signal contact TC20.

[0161] The contact (first data contact) TC08 arranged next to the SCLK contact TC07 on the opposite side of the attachment detection contact TC06 sends MOSI (first data signal). Since MOSI is a data signal, MOSI seems to be vulnerable to clock noise. However, MOSI is the data signal of the same SPI communication standard as the clock signal sent by the SCLK contact TC07, so the potential fluctuation timing is synchronized with the clock signal and it is less likely to be affected by clock noise. Therefore, the contact TC08 does not have to be fixed to the GND potential and can be used as the MOSI contact.

[0162] The accessory 200 has a battery 205 and receives power supply from the battery 205, and also receives power supply from the camera 100 via the camera connector 141 and the accessory connector 211. The accessory control circuit 201, which is the control unit of the accessory 200, is a circuit that controls the entire accessory 200 and includes a processor (microcomputer) including a CPU and the like.

[0163] The accessory power supply circuit 202 is a circuit that generates a power supply for supplying power to each circuit in the accessory 200, and includes a DC / DC converter circuit, an LDO, a charge pump circuit, etc. The 1.8V voltage generated by the accessory power supply circuit 202 is constantly supplied as the accessory microcomputer power supply VMCU_A to the accessory control circuit 201. The voltage generated by the accessory power supply circuit 202 can be different from 1.8V. The control of the accessory power supply circuit 202 can provide on / off control of the power supply to each circuit in the accessory 200.

[0164] The charging circuit 204 is a circuit that charges the battery 205 using the power supplied from the camera 100. When the accessory control circuit 201 can determine that sufficient power has been supplied from the camera 100 for the charging operation, the accessory control circuit 201 controls the charging circuit 204 to charge the battery 205. In this embodiment, the battery 205 is attached to the accessory 200, but the accessory 200 can operate only by the power supply from the camera 100 without the battery 205 attached. In this case, the charging circuit 204 is unnecessary.

[0165] The differential communication circuit 207 is a circuit for differential communication with the camera 100 and can communicate data with the camera 100. The external communication IF circuit 208 is an IF circuit for data communication with an external device (not shown), such as an Ethernet communication IF, a wireless LAN communication IF, and a public network communication IF, etc. The accessory control circuit 201 controls the differential communication circuit 207 and the external communication IF circuit 208 to send the data received from the camera 100 to the external device and send the data received from the external device to the camera 100.

[0166] The function circuit 206 is a circuit that has different functions according to the type of the accessory 200. When the accessory 200 is a flash device, the function circuit 206 is, for example, a light emitting circuit or a charging circuit, etc. When the accessory 200 is a microphone device, the accessory 200 is a voice codec circuit or a microphone circuit, etc.

[0167] The external connection terminal 209 is a connector terminal for connection to an external device, and is a USB TYPE-C connector in this embodiment. The connection detection circuit 210 is a circuit for detecting that an external device has been connected to the external connection terminal 209. The accessory control circuit 201 can detect the connection of the external device to the external connection terminal 209 by receiving the output signal of the connection detection circuit 210.

[0168] The power switch 203 is a switch for turning on and off the operation of the accessory 200. The accessory control circuit 201 can detect the on position and the off position by reading the signal level of the terminal to which the power switch 203 is connected.

[0169] The operation switch 212 is a switch for operating the accessory 200 and includes a button, a cross key, a slide switch, a dial switch, etc. When the operation switch 212 is operated, the accessory control circuit 201 detects the operation and performs a predetermined process according to the operation.

[0170] The accessory connector 211 is a connector that can be electrically connected to the camera 100 via 21 contacts TA01 to TA21 arranged in a row. The contacts TA01 to TA21 are arranged in the order of contacts TA01 to TA21 from one end to the other end of the arrangement direction.

[0171] The contact TA01 is connected to GND and is used not only as a reference potential contact but also as a contact for controlling the wiring impedance of the differential signals D1N and D1P. The contact TA01 corresponds to the third ground contact.

[0172] The differential signal D1N connected to the contact TA02 and the differential signal D1P connected to the contact TA03 are data communication signals for data communication in pairs, and are connected to the differential communication circuit 207. The contacts TA02, TA03, TA07 to TA17, TA19, and TA20 described below are communication contacts.

[0173] The contact TA04 as the first ground contact is connected to GND and is used as a reference potential contact for the camera 100 and the accessory 200. The contact TA04 is arranged outside the contact TA05 described below along the arrangement direction of the contacts. The accessory power circuit 202 and the charging circuit 204 are connected to TA05 as a power contact, and the accessory power VACC supplied from the camera 100 is connected to the contact TA05. The contact TA06 as an attachment detection contact is directly connected to GND. When the accessory 200 is attached to the camera 100, the contact TA06 makes the above-mentioned accessory attachment detection signal / ACC_DET become low level (GND potential). Thus, the camera 100 can detect the attachment of the accessory 200. The SCLK connected to the contact TA07 as a communication contact, the MOSI connected to the contact TA08, the MISO connected to the contact TA09, and the CS connected to the contact TA10 are signals for the accessory control circuit 201 to be used as a communication slave device for SPI communication.

[0174] A communication request signal / WAKE for requesting communication from the accessory control circuit 201 to the camera 100 is connected to the contact TA11. When the accessory control circuit 201 determines that communication with the camera 100 is required, the accessory control circuit 201 requests communication from the camera 100 by changing the communication request signal / WAKE to a low output.

[0175] When power is supplied to the accessory 200 from the camera control circuit 101 via TC5 in response to detection of the attachment of the accessory 200, the accessory control circuit 201 notifies the camera control circuit 101 of the receipt of power supply by changing the signal level (by changing the potential of the communication request signal / WAKE) of the communication request signal / WAKE from a high level to a low level.

[0176] Even if there is no request from the camera, the accessory control circuit 201 can notify the existence of a factor enabling communication between the accessory 200 and the camera 100 by changing the signal level (potential) of the communication request signal / WAKE from a high level to a low level. With this configuration, the camera control circuit 101 can omit the operation of periodically checking by polling whether the accessory 200 has a factor requiring communication. When a communication requirement factor occurs, the accessory 200 can communicate with the camera 100 in real time.

[0177] SDA connected to the contact TA12 as a communication contact and SCL connected to the contact TA13 are signals for the accessory control circuit 201 to be used as a communication slave device for I2C communication.

[0178] The FNC1 signal connected to the contact TA14, the FNC2 signal connected to the contact TA15, the FNC3 signal connected to the contact TA16, and the FNC4 signal connected to the contact TA17 are function signals whose functions are variable according to the type of the accessory 200. For example, when the accessory 200 is a microphone device, these signals can be voice data signals, and when the accessory 200 is a flash device, these signals can be signals for notifying the light emission timing.

[0179] The contact TA18 as a second ground contact is also connected to GND and, similar to the contact TA04, is a reference potential contact for the camera 100 and the accessory 200. The differential signal D2N connected to the contact TA19 and the differential signal D2P connected to the contact TA20 are data communication signals for performing data communication in pairs and are connected to the external connection terminal 209. The contact TA21 is connected to GND and can be used not only as a reference potential contact but also as a terminal for controlling the wiring impedance of the differential signals D2N and D2P. TA21 corresponds to the fourth ground contact.

[0180] The contacts TA01, TA04, TA06, TA18, and TA21 are connected to the GND portion of, for example, an FPC substrate, and the GND portion of the FPC substrate is fixed to a metal member serving as the GND level of the accessory 200 using screws (not shown). The metal member serving as the GND level includes, for example, socket attachment legs that can be engaged with the accessory socket portion of the camera 100, and a bottom plate (not shown) inside the accessory 200, etc.

[0181] Figure 5 Illustrate the operations (processing) of the camera 100 and the accessory 200 when the accessory 200 is attached to the camera 100. The processing of the camera 100 and the accessory 200 will be described in detail below.

[0182] When the accessory 200 is attached to the camera 100, the accessory attachment detection signal / ACC_DET becomes at the GND level, and the camera control circuit A 101 determines that the accessory 200 is attached to the camera 100. When the camera control circuit A 101 determines that the accessory 200 is attached, the camera control circuit A 101 sets the power control signal CNT_VACC1 to the high level to turn on the output of the accessory power circuit A 131. As soon as the power control signal CNT_VACC1 becomes at the high level, the accessory power circuit A131 outputs the accessory power VACC.

[0183] When the accessory power circuit 202 in the accessory 200 receives VACC, the accessory power circuit 202 generates the power VMCU_A for the accessory control circuit 201, and the accessory control circuit 201 starts. After the accessory control circuit 201 starts, the accessory control circuit 201 initializes each block in the accessory 200. After that, when the accessory control circuit 201 is ready to communicate with the camera 100, the accessory control circuit 201 sets the communication request signal / WAKE to the low level.

[0184] In the camera 100, the camera control circuit A 101 detects that the accessory 200 is in a communicable state by detecting that the / WAKE terminal becomes at the low level. The camera control circuit A 101 requests accessory information through I2C communication.

[0185] In the accessory 200, the accessory control circuit 201 sends accessory information in response to the accessory information request from the camera 100. The accessory control circuit 201 sets the communication request signal / WAKE to the high level when sending the accessory information.

[0186] In the camera 100, the camera control circuit A 101 determines whether the attached accessory is controllable or not by judging the received accessory information. The camera control circuit A 101 turns on the accessory power supply circuit B 132. When the camera control circuit A 101 finishes various settings of the camera 100, it notifies the accessory information to the camera control circuit B 102. The camera control circuit B 102 provides the notification of the control command and the control of the function signal to the accessory 200 through SPI communication based on the accessory type information. The accessory control circuit 201 responds to the control command from the camera 100 through SPI communication and controls according to the function signal.

[0187] Now, the Figure 4 accessory information shown will be described. The D7 - D0 data at address 0x00 is the information indicating the type of the accessory. Figure 6 The accessory type information as the accessory information will be described. For example, 0x81 indicates a flash device, 0x82 indicates an interface conversion adapter device, 0x83 indicates a microphone device, and 0x84 indicates a multi - accessory connection adapter device for attaching multiple accessory devices to the camera 100.

[0188] Here, the adapter device is an intermediate accessory attached between the camera 100 and accessories such as a flash device and a microphone device. The interface conversion adapter device is an adapter device that converts the interface to provide compatibility between the camera 100 and the accessory when the interfaces of the camera 100 and the accessory are different. The multi - accessory connection adapter device is an adapter device to which multiple accessories can be attached.

[0189] The D7 - D0 data at address 0x01 is the information indicating the model of the accessory 200. The model of the accessory can be uniquely identified by the above - mentioned accessory type information and this information. The D7 - D0 data at address 0x02 is the information indicating the firmware version of the accessory 200.

[0190] The D7-D6 data at address 0x03 is information indicating whether to request the supply of the accessory power VACC to the accessory 200 in a state where a power switch (not shown) of the camera 100 is turned off. When this information is 0, power supply is not requested. When this information is 1, the accessory power supply circuit A 131 requests power supply. When this information is 2, the accessory power supply circuit B 132 requests power supply. The D5-D4 data at address 0x03 is information indicating whether to request the supply of the accessory power VACC to the accessory 200 when the camera 100 is in the power saving mode. When this information is 0, it means that power supply is not required. When this information is 1, it means that there is a power supply request from the accessory power supply circuit A 131. When this information is 2, it means that there is a power supply request from the accessory power supply circuit B 132. The D3-D2 data at address 0x03 is information indicating whether the accessory 200 has the battery 205. When this information is 0, it means that the accessory 200 does not have a battery, and when this information is 1, it means that the accessory 200 has a battery. The D1-D0 data at address 0x03 is information indicating whether the accessory 200 has a charging function for the battery 205. When this information is 0, it means that the accessory 200 does not have a charging function, and when this information is 1, it means that the accessory 200 has a charging function.

[0191] The D7-D0 data at address 0x04 is information indicating the required power of the accessory power VACC supplied from the camera 100 to the accessory 200. The value obtained by multiplying this information by 10 represents the current value. When this information is 10, it means 100 mA, and when this information is 100, it means 1 A.

[0192] To reduce the amount of information of this information, this information can be simply associated with an arbitrary current value. For example, when this information is 0, it can mean 100 mA, when this information is 1, it can mean 300 mA, when this information is 3, it can mean 450 mA, and when this information is 4, it can mean 600 mA.

[0193] The D7 data at address 0x05 is information indicating whether the accessory 200 is in the firmware update mode state (information indicating the operation mode of the accessory 200). When this information is 0, it means that the accessory 200 is not in the firmware update mode state, and when this information is 1, it means that the accessory 200 is in the firmware update mode state. The D6 data at address 0x05 is information indicating whether the accessory 200 has the firmware update function. When this information is 0, it means that the accessory 200 does not have the firmware update function. When this information is 1, it means that the accessory 200 has the firmware update function. The D5-D4 data at address 0x05 is information indicating whether the operation of the accessory 200 attached to the intermediate (connected) accessory is permitted (supported). When this information is 0, it means that the operation is not permitted, and when this information is 1, it means that the operation is permitted. The D3-D2 data at address 0x05 is information indicating whether the accessory 200 needs the camera 100 to confirm the attachment state of the intermediate accessory when the camera 100 is started. When this information is 0, it means that the confirmation is unnecessary, and when this information is 1, it means that the confirmation is necessary. The D1-D0 data at address 0x05 is information indicating whether the accessory 200 supports command notification via I2C communication. When this information is 0, it means that command notification is not supported, and when this information is 1, it means that command notification is supported.

[0194] The D5-D4 data at address 0x06 is information indicating the following communication method, which can be used to notify the camera 100 of the factor of the communication request after the accessory 200 notifies the camera 100 of the communication request signal / WAKE. When this information is 0, it means that the I2C communication method is supported. When this information is 1, it means that the SPI communication method is supported. When this information is 2, it means that both the I2C communication method and the SPI communication method are supported. The D3-D0 data at address 0x06 is information indicating whether the accessory 200 has functions corresponding to the FNC1 signal, FNC2 signal, FNC3 signal, and FNC4 signal. The D0 data corresponds to the FNC1 signal, the D1 data corresponds to the FNC2 signal, the D2 data corresponds to the FNC3 signal, and the D3 data corresponds to the FNC4 signal. When this value is 0, it means that the accessory 200 does not have this function. When this value is 1, the accessory 200 has this function.

[0195] The D7 data at address 0x0A is information indicating whether the accessory 200 requests the camera 100 to start when the accessory 200 notifies the camera 100 of a communication request signal / WAKE. When this information is 0, it means a start request, and when this information is 1, it means no start request. The D6 - D0 data at address 0x0A is information indicating the factor for the accessory 200 to notify the camera 100 of the communication request signal / WAKE. Figure 7 Describe the factor number and factor content of the communication request, and illustrate an example of the factor of the communication request signal / WAKE. In this example, the accessory 200 is a microphone device. For example, the factor number 0x00 is the number indicating that the menu call switch in the operation switch 212 is pressed. The factor number 0x01 is the number indicating that the accessory 200 has completed the output control of the audio signal. The factor number 0x02 is the number indicating that the accessory 200 has completed the mute processing of the audio signal. Therefore, information related to the generation factor of the communication request signal / WAKE can be notified to the camera 100.

[0196] The D1 data at address 0x0C is information indicating the SPI communication protocol supported by the accessory 200. When this information is 0, it means the accessory 200 supports SPI protocol A, and when this information is 1, it means the accessory 200 supports SPI protocol B. The D0 data at address 0x0C is information indicating the control logic of the CS signal in the SPI communication supported by the accessory 200. When this information is 0, it means the CS signal is low - active logic, and when this information is 1, it means the CS signal is high - active logic. The D7 - D0 data at address 0x0D is information indicating the time required as the communication byte interval when the accessory 200 communicates according to SPI protocol A and the D7 data at address 0x05 is 0, or when the accessory 200 is not in the firmware update mode state. The D7 - D0 data at address 0x0E is information indicating the time required as the communication byte interval when the accessory 200 communicates according to SPI protocol A and the D7 data at address 0x05 is 1, or when the accessory 200 is in the firmware update mode state.

[0197] Figure 8A and Figure 8B Describe the communication data interval information related to SPI communication, and illustrate the relationship between the time between communication bytes (communication interval) and the information related to the data at address 0x0D and the data at address 0x0E. Figure 8A Illustrate the relationship between the time between communication bytes and the data at address 0x0D, and Figure 8BIllustrate the relationship between the time between communication bytes and the data at address 0x0E. The D7 - D0 data at address 0x0F is information representing the checksum.

[0198] Figure 9 is a flowchart illustrating the operation of the camera control circuit A, and illustrates the processing of the camera control circuit A101 from when the accessory 200 is attached to the camera 100 until the function of the accessory 200 is enabled.

[0199] In step S401, the camera control circuit A 101 monitors the signal level of the accessory attachment detection signal / ACC_DET, and determines (detects) whether the accessory 200 is attached. When the signal level of the accessory attachment detection signal / ACC_DET is high, the camera control circuit A 101 determines that the accessory 200 has not been attached, and the process returns to step S401 to determine again whether the accessory 200 is attached. When the signal level is low, the camera control circuit A 101 determines that the accessory 200 is attached, and the process proceeds to step S402.

[0200] In step S402, the camera control circuit A 101 performs control to change the power control signal CNT_VACC1 to a high level to turn on the output of the accessory power supply circuit A 131, and the process proceeds to step S403. When the power control signal CNT_VACC1 becomes high, the accessory power supply circuit A 131 outputs the accessory power VACC.

[0201] In step S403, the camera control circuit A 101 monitors the signal level of the overcurrent detection signal DET_OVC, and determines whether an overcurrent is flowing. When the signal level of DET_OVC is low, the camera control circuit A101 determines that no overcurrent is flowing, and the process proceeds to step S404, and when the signal level is high, the camera control circuit A 101 determines that an overcurrent is flowing, and the process proceeds to step S405 for error handling.

[0202] In step S404, the camera control circuit A101 monitors the signal level of the communication request signal / WAKE, which is a notification signal from the accessory 200, and determines whether the initialization of the accessory 200 is complete. If the signal level of the communication request signal / WAKE is low, the camera control circuit A 101 determines that the initialization is complete, and the process proceeds to step S406. If the signal level is high, the camera control circuit A 101 determines that the initialization is not complete, and the process returns to step S404, so that the camera control circuit A 101 determines again whether the initialization is complete.

[0203] In step S406, the camera control circuit A 101 performs I2C communication with the accessory 200 and reads 15 bytes of accessory information. Then, the process proceeds to step S407. In step S407, the camera control circuit A 101 determines whether the attached accessory 200 is compatible with the camera 100 based on the accessory information read in step S406. If the camera control circuit A 101 determines that the attached accessory 200 is compatible, the process proceeds to step S408, and if the camera control circuit A 101 determines that the attached accessory 200 is incompatible, the process proceeds to step S409 for error handling.

[0204] In step S408, the camera control circuit A 101 performs control to change the power control signal CNT_VACC2 to a high level to turn on the output of the accessory power supply circuit B 132. Then, the process proceeds to step S410. When the power control signal CNT_VACC2 becomes high, the accessory power supply circuit B 132 outputs the accessory power VACC. In this embodiment, when control is performed so that both the power control signals CNT_VACC1 and CNT_VACC2 are high, the output from the accessory power supply circuit B 132 is supplied to the accessory power VACC. In step S410, the camera control circuit A101 notifies the camera control circuit B 102 of the accessory information read in step S406 to complete the startup process of the camera 100 in response to the attachment of the accessory 200.

[0205] Figure 10 It is a flowchart of the operation of the camera control circuit B 102 from when the accessory 200 is attached to the camera 100 until the function of the accessory 200 is enabled.

[0206] In step S501, the camera control circuit B 102 determines whether accessory information has been notified from the camera control circuit A101. If the accessory information has not been notified, the process returns to step S501, and the camera control circuit B 102 determines again whether the accessory information has been notified (performs a detection operation). If the accessory information has been notified, the process proceeds to step S502.

[0207] In step S502, the camera control circuit B 102 sets the function signals FNC1 to FNC4 based on the accessory information notified from the camera control circuit A 101. For example, when it is notified that the accessory 200 is a microphone device, FNC1 is set to be used as the voice data clock signal BCLK, FNC2 is set to be used as the voice data channel signal LRCLK, and FNC3 is set to be used as the voice data signal SDAT. As another example, when it is notified that the accessory 200 is a flash device, FNC4 is set to be used as the flash emission synchronization signal XOUT. For the function signals that do not require control of the accessory 200, the camera control circuit B 102 makes a predetermined setting so as not to interfere with the operations of the camera 100 and the accessory 200.

[0208] Next, in step S503, the camera control circuit B 102 sets the CS control logic in the SPI communication based on the accessory information notified from the camera control circuit A101. Next, in step S504, the camera control circuit B 102 determines (detects) whether a predetermined event for the accessory 200 has occurred. If the event has not occurred, the process returns to step S504, and the camera control circuit B 102 determines (detects) again whether the event has occurred. If the event has occurred, the process proceeds to step S505.

[0209] In step S505, the camera control circuit B 102 determines whether the event determined in step S504 is an event that requires SPI communication with the accessory 200. If the detected event is an event that requires SPI communication, the process proceeds to step S506. If the detected event is not an event that requires SPI communication, the process proceeds to step S507.

[0210] In step S507, the camera control circuit B 102 determines whether the event determined in step S504 is an event that requires control of the accessory 200 using the function signal. If the detected event is an event that requires control using the function signal, the process proceeds to step S508, and if the detected event is not an event that requires control using the function signal, the process proceeds to step S509.

[0211] In step S506, the camera control circuit B 102 performs SPI communication with the accessory 200. When the accessory 200 is a microphone device, the SPI communication performed in step S506 includes, for example, communication of an instruction to turn on or off the microphone operation, communication of an instruction to switch the sound collection directivity of the microphone, and communication of an instruction to switch the equalizer function of the microphone. When the accessory 200 is a flash device, the SPI communication includes communication for reading out setting information related to the flash device and communication for notifying the flash device of the setting information. When the SPI communication in step S506 is completed, the process returns to step S504, and the camera control circuit B 102 determines again whether an event has occurred.

[0212] In step S508, the camera control circuit B 102 controls the accessory 200 using function signals. For example, when the accessory 200 is a microphone device, the camera control circuit B 102 outputs the audio data clock signal BCLK of FNC1 and the audio data channel signal LRCLK of FNC2, and receives the audio data signal SDAT of FNC3. Thereby, the camera 100 can acquire voice data from the accessory 200. When the accessory 200 is a flash device, the camera control circuit B 102 controls the flash emission synchronization signal XOUT of FNC4 at a predetermined timing. Thereby, the camera 100 can instruct the flash device to emit light. When the control using the predetermined function signal in step S508 is completed, the process returns to step S504, and the camera control circuit B 102 detects again whether an event has occurred.

[0213] In step S509, the camera control circuit B 102 performs predetermined in-camera control according to the event detected in step S504. When the accessory 200 is a microphone device, the in-camera control performed through step S509 includes, for example, control for starting or ending the recording of voice data in the recording memory 126 and control for performing equalizer processing on the voice data. When the accessory 200 is a flash device, the in-camera control includes photometric control for using the image sensor 122 to accumulate and acquire the light emitted by the flash device and control for calculating an indication value of the light emission amount of the flash device. When the in-camera control in step S509 is thus completed, the process returns to step S504, and the camera control circuit B 102 detects again whether an event has occurred.

[0214] As described above, the camera 100 can control the attached accessory 200 according to the Figure 9 and Figure 10 flowchart.

[0215] Figure 11 is a flowchart illustrating the operation of the accessory control circuit 201, and illustrates the processing of the accessory control circuit 201 from when the accessory 200 is attached to the camera 100 until the functions of the accessory 200 are operated.

[0216] In step S601, the accessory control circuit 201 waits for the accessory power supply VACC from the camera 100 to be turned on. In the case where the accessory 200 does not have the battery 205, when power is supplied to the accessory control circuit 201 and the operation of the accessory control circuit 201 itself starts, the turning on of the accessory power supply VACC can be detected. In the case where the accessory 200 has the battery 205, in addition to the above function, even when the accessory control circuit 201 monitors the voltage value of the accessory power supply VACC, the accessory control circuit 201 can also detect the turning on of the accessory power supply VACC. When the accessory power supply VACC is turned on, the process proceeds to step S602.

[0217] In step S602, the accessory control circuit 201 performs predetermined initial settings. For example, the accessory control circuit 201 sets the operation frequency of the microcomputer, the input / output control ports of the microcomputer, the initialization of the timer function of the microcomputer, and the initialization of the interrupt function of the microcomputer. When the initial settings in step S602 are completed, the process proceeds to step S603. In step S603, the accessory control circuit 201 performs control to change the communication request signal / WAKE to a low output, and notifies the camera 100 that the initial settings are completed.

[0218] Next, in step S604, the accessory control circuit 201 responds to the I2C communication from the camera 100 and transmits 15-byte accessory information. As described above, the accessory information includes Figure 4 the various information shown. When the initial communication in step S604 is completed, the process proceeds to step S605. In step S605, the accessory control circuit 201 performs control to change the communication request signal / WAKE to a high level. When the initial communication is completed, the process proceeds to step S606. In step S606, the accessory control circuit 201 determines (detects) whether a predetermined event has occurred. If no event has occurred, the process returns to step S606, and the accessory control circuit 201 determines (detects) again whether an event has occurred, and if an event has occurred, the process proceeds to step S607.

[0219] In step S607, the accessory control circuit 201 determines whether the event determined in step S606 is an event that requires SPI communication with the camera 100. If the detected event is an event that requires SPI communication, the process proceeds to step S608, and if the detected event is not an event that requires SPI communication, the process proceeds to step S609.

[0220] In step S609, the accessory control circuit 201 determines whether the event determined in step S606 is an event that requires I2C communication with the camera 100. If the detected event is an event that requires I2C communication, the process proceeds to step S610, and if the detected event is not an event that requires I2C communication, the process proceeds to step S611.

[0221] In step S611, the accessory control circuit 201 determines whether the event detected in step S606 is an event that requires control using a function signal. If the detected event is an event that requires control using a function signal, the process proceeds to step S612, and if the detected event is not an event that requires control using a function signal, the process proceeds to step S613.

[0222] In step S613, the accessory control circuit 201 determines whether the event detected in step S606 is an event that is notified to the camera 100 via a communication request signal / WAKE. If the detected event is an event that is notified to the camera 100 via a communication request signal / WAKE, the process proceeds to step S614, and if the detected event is not an event that is notified to the camera 100 via a communication request signal / WAKE, the process proceeds to step S615.

[0223] In step S608, the accessory control circuit 201 performs SPI communication with the camera 100. When the communication request signal / WAKE is in a low output state during the execution of SPI communication by the accessory control circuit 201, the accessory control circuit 201 performs control to change the communication request signal / WAKE to a high output state after the SPI communication. When the accessory 200 is a microphone device, the SPI communication includes, for example, communication for an instruction to turn on the microphone operation from the camera 100, communication for an instruction to turn off the microphone operation, and communication for an instruction to switch the sound collection directivity of the microphone. The SPI communication also includes communication for an instruction to switch the equalizer function of the microphone. When the accessory 200 is a flash device, the SPI communication includes communication for reading setting information related to the flash device and communication for notifying the flash device of the setting information. When the predetermined SPI communication in step S608 is completed, the process returns to step S606, and the accessory control circuit 201 detects again whether an event has occurred.

[0224] In step S610, the accessory control circuit 201 performs I2C communication with the camera 100. When the communication request signal / WAKE is in the low output state during the execution of SPI communication, control is performed to change the communication request signal / WAKE to the high output state after the I2C communication. The I2C communication performed in step S610 includes, for example, communication for reading out the communication request factor of the signal notification of the communication request signal / WAKE that the accessory control circuit 201 has notified the camera 100. When the predetermined I2C communication in step S610 is completed, the process returns to step S606, and the accessory control circuit 201 detects again whether an event has occurred.

[0225] In step S612, the accessory control circuit 201 controls the camera 100 using function signals. When the accessory 200 is a microphone device, this control includes, for example, reception control of the audio data clock signal BCLK of FNC1 and the audio data channel signal LRCLK of FNC2 output from the camera 100, and output control of the voice data signal SDAT of FNC3 synchronized with these signals. When the accessory 200 is a flash device, this control includes reception control of the flash emission synchronization signal XOUT of FNC4 for flash emission control. When the control using function signals in step S612 is completed, the process returns to step S606, and the accessory control circuit 201 detects again whether an event has occurred.

[0226] In step S614, the accessory control circuit 201 stores the communication request factor number for the camera 100 in response to the event determined in step S606 in a volatile memory (not shown) of the accessory 200, and performs control to change the communication request signal / WAKE to the low output. As referred to Figure 7 above, the communication request factor number is a unique number assigned to each factor content. When the low output control of the communication request signal / WAKE in step S614 is completed, the process returns to step S606, and the accessory control circuit 201 determines again whether an event has occurred.

[0227] In step S615, the accessory control circuit 201 performs in-accessory control according to the event determined in step S606. When the accessory 200 includes a battery 205, the in-accessory control performed in step S615 includes, for example, control for detecting the remaining battery level and control for detecting the operation of the operation switch 212. When the in-accessory control in step S615 is completed, the process returns to step S606, and the accessory control circuit 201 detects again whether an event has occurred.

[0228] According to Figure 11The flowchart shows that after the accessory 200 is attached to the camera 100, the accessory 200 can perform functional operations.

[0229] Now referring to Figures 9 to 11 , the process for determining the SPI communication method between the camera 100 and the accessory 200 will be described. Descriptions of the already described content will be omitted.

[0230] In Figure 9 step S406, the camera control circuit A 101 performs I2C communication with the accessory 200 and reads the accessory information related to SPI communication as shown in Figure 4 . As described above, all 15 bytes of accessory information can be read. Optionally, a part of the accessory information including the D1 data at address 0x0C, the D0 data at address 0x0C, and the D7 - D0 data at address 0x0D in the accessory information related to SPI communication can be read. Figure 4

[0231] In step S410, the camera control circuit A 101 notifies the camera control circuit B 102 of the information related to SPI communication read in step S406. The information to be notified may include information other than the read accessory information.

[0232] In Figure 10 step S501, the camera control circuit B 102 obtains the information related to SPI communication from the camera control circuit A101 through I2C communication. As described above, the obtained information may include information other than the information related to SPI communication.

[0233] In step S503, the camera control circuit B 102 sets the SCLK signal, CS signal, MOSI signal, and MISO signal for performing SPI communication. Regarding the CS signal, the initial state of the signal is set based on the D0 data at address 0x0C in the accessory information obtained in step S501. If the D0 data at address 0x0C in the accessory information is 0, the initial state of the CS signal is set to high level. If the D0 data at address 0x0C in the accessory information is 1, the initial state of the CS signal is set to low level.

[0234] In step S506, the camera control circuit B 102 performs SPI communication control based on the D1 data at address 0x0C in the accessory information obtained in step S501 and the D7 - D0 data at address 0x0D in this accessory information. If the D1 data at address 0x0C in the accessory information is 0, the camera control circuit B 102 determines that the accessory 200 supports SPI protocol A, and according to the above Figure 2CPerform SPI communication according to the flowchart.

[0235] In Figure 2C step S103, the camera control circuit B 102 performs a waiting process for a predetermined time T_CS. The predetermined time T_CS is a predetermined value, and in this embodiment, a waiting process of 50 μs is performed. In Figure 2C step S108, the camera control circuit B 102 performs Figure 8A a time waiting process for the communication interval corresponding to the D7 - D0 data at address 0x0D in the accessory information as shown, as the predetermined time T_INTERVAL. When the D7 - D0 data at address 0x0D in the accessory information is 7, a waiting process of 100 μs is performed in this embodiment.

[0236] Therefore, when the D1 data at address 0x0C in the accessory information is 0, the information related to the communication interval (waiting process time) in the SPI communication is uniquely set based on the D7 - D0 data at address 0x0D in the accessory information obtained through I2C communication. This configuration enables communication suitable for the SPI communication function of the accessory 200.

[0237] This embodiment exemplifies an example where the D7 data at address 0x05 in the accessory information is 0 (i.e., the accessory 200 is not in the firmware update mode state). On the other hand, when the D7 data at address 0x05 in the accessory information is 1, the following operations are performed. That is, as Figure 2C the predetermined time T_INTERVAL in step S108, a time waiting process for the communication interval corresponding to the D7 - D0 data at address 0x0E in the accessory information as shown is performed. For example, when the D7 - D0 data at address 0x0E in the accessory information is 7, a waiting process of 100 ms is performed. Figure 8B

[0238] Generally, in the firmware update operation, program operations of non - volatile memories such as flash microcomputers are required. Since the processing time required for the program operation may be longer than the processing time required for the accessory function processing, obtaining the accessory information for the firmware update mode state enables SPI communication suitable for the firmware update operation.

[0239] Figure 2E When the D1 data at address 0x0C in the accessory information is 1, the camera control circuit B102 determines that the accessory 200 corresponds to the SPI protocol B, and according to the above - mentioned Figure 2EPerform SPI communication according to the flowchart. Therefore, when the D1 data at address 0x0C in the accessory information is 1, confirm whether the accessory 200 is in the SPI communicable state based on the potential of the MISO signal. This configuration enables communication suitable for an accessory where the communication interval (waiting processing time) in SPI communication is not uniquely determined. As described above, obtaining accessory information related to the SPI communication function of the accessory 200 through I2C communication and controlling based on this accessory information enables communication suitable for the SPI communication function of the accessory.

[0240] In Figure 11 In step S602, the accessory control circuit 201 performs a predetermined initial setting and sets the SCLK signal, CS signal, MOSI signal, and MISO signal used for SPI communication. For the CS signal, set the communication request interrupt based on the D0 data at address 0x0C in the accessory information. When the D0 data at address 0x0C in the accessory information is 0, set it so that the low edge of the CS signal can be interrupted and detected. When the D0 data at address 0x0C in the accessory information is 1, set it so that the high edge of the CS signal can be interrupted and detected.

[0241] In step S604, the accessory control circuit 201 responds to the I2C communication from the camera 100 and sends the accessory information. In step S608, the accessory control circuit 201 performs SPI communication control based on the D1 data at address 0x0C in the accessory information notified to the camera 100 in step S604 and the D7 - D0 data at address 0x0D in this accessory information. When the accessory control circuit 201 supports SPI protocol A, the D1 data at address 0x0C in the accessory information is 0, so perform SPI communication according to the Figure 2D flowchart above. Therefore, when the D1 data at address 0x0C in the accessory information is 0, communicate at the communication interval (waiting processing time) according to the D7 - D0 data at address 0x0D in the accessory information notified to the camera 100 through I2C communication in step S604. Thus, communication suitable for the SPI communication function of the accessory 200 becomes available. When the accessory control circuit 201 supports SPI protocol B, the D1 data at address 0x0C in the accessory information is 1, so perform SPI communication according to the Figure 2F flowchart above.

[0242] As described above, in step S212, the accessory control circuit 201 confirms whether SPI communication is available and changes the level of the MISO signal according to the confirmation result (steps S213 and S214). For example, when the accessory 200 is a flash device, in order to control the light emission timing with an accuracy of several μs, it is necessary not to accept communication with the camera 100 during the light emission control. In this case, the accessory control circuit 201 performs control to change the MISO signal to a low level so that the camera 100 can wait for communication, and can receive the following commands by performing control to change the MISO signal to a high level after the light emission control is completed. Therefore, control using SPI protocol B can be executed in accessories that require precise control of the operation timing of the accessory 200 on the order of several microseconds.

[0243] In this embodiment, an example is illustrated in which the D7 data at address 0x05 in the accessory information is 0 (i.e., the accessory 200 is not in the firmware update mode state). On the other hand, when the D7 data at address 0x05 in the accessory information is 1, the camera 100 performs Figure 8B the time waiting process of the communication interval corresponding to the D7-D0 data at address 0x0E in the accessory information as shown, and performs SPI communication with the accessory 200. For example, when the D7-D0 data at address 0x0E in the accessory information is 7, a 100 ms waiting process is notified to the camera 100.

[0244] Generally, program operations in a non-volatile memory such as a flash microcomputer are required in the firmware update operation. Since the processing time required for the program operation may be longer than the processing time required for the accessory function processing, the accessory information for obtaining the firmware update mode state enables SPI communication suitable for the firmware update operation.

[0245] Figure 12A Examples illustrating the relationship between the communication content in SPI protocol A and the operation of the accessory 200 are given, and Figure 12B examples illustrating the relationship between the communication content in SPI protocol B and the operation of the accessory 200 are given. Figure 12A Examples are given in which the camera 100 notifies the accessory 200 of command 0x11 and command 0x12, respectively. In this embodiment, the accessory 200 is a microphone device. These examples illustrate communication with a communication interval of 50 μs (the D7-D0 data of 0x0D is 6).

[0246] Command 0x11 is a command indicating a volume change instruction, and the MOSI data of the second byte represents the volume value. In Figure 12AIn the example, 0x60 is specified as the volume value. The accessory control circuit 201 that receives the volume change indication controls the codec. This embodiment assumes that the time required to control the codec is 20 μs.

[0247] Command 0x12 is a command for indicating the turn-on and turn-off of voice data output. When the MOSI data in the second byte is 0, this means turning off the voice data output, and when the MOSI data is 1, this means turning on the voice data output. In Figure 12A the example, an indication to turn off the audio data output is issued. The accessory control circuit 201 that receives the indication to turn off the audio data output controls the codec. Similar to command 0x11, the time required to control the codec is 20 μs.

[0248] Generally, compared with the accessory control circuit 201 for implementing SPI protocol B, the accessory control circuit 201 for implementing SPI protocol A can be manufactured at a lower cost, so that for accessories with a small difference in processing time in response to an indication from the camera 100, control using SPI protocol A can be used.

[0249] Figure 12B An example of issuing command 0x01 from the camera 100 to the accessory 200 twice is illustrated. In this embodiment, the accessory 200 is a flash device.

[0250] Command 0x01 is a command representing a light emission indication, and the MOSI data in the second byte means the light emission amount. In Figure 12B the example, the first command indicates 0x80 as the light emission amount, and the second command indicates 0x10 as the light emission amount. The accessory control circuit 201 that receives the light emission indication prepares for light emission. The time required to prepare for light emission depends on the light emission amount, and it is assumed that 100 μs is required when the light emission amount is 0x80 and 70 μs is required when the light emission amount is 0x10. The accessory control circuit 201 performs control to change MISO to a low level until the light emission preparation is completed, and notifies the camera control circuit B 102 that SPI communication is unavailable. When the light emission preparation is completed, the accessory control circuit 201 performs control to change MISO to a Hi level, and notifies the camera control circuit B 102 that SPI communication is available.

[0251] When the transfer of the fourth byte is completed, the accessory control circuit 201 performs a light-emitting process. The time required for the light-emitting process depends on the amount of light emission, and it is assumed that 150 μs is required when the amount of light emission is 0x80 and 30 μs is required when the amount of light emission is 0x10. The accessory control circuit 201 performs control to change MISO to a low level until the light-emitting process is completed, and notifies the camera control circuit B 102 that SPI communication is unavailable. When the light-emitting process is completed, the accessory control circuit 201 performs control to change MISO to a high level, and notifies the camera control circuit B 102 that SPI communication is available.

[0252] Therefore, if an accessory with time fluctuations in command processing is controlled using SPI protocol A, it is necessary to set the communication interval to the longest processing time, so the control becomes redundant. Therefore, an accessory with time fluctuations in command processing can be controlled using SPI protocol B.

[0253] As described above, it is possible to control communication suitable for the SPI communication function of the accessory by using I2C communication to notify accessory information related to the SPI communication function of the accessory 200 and performing SPI communication control based on this accessory information.

[0254] As described above, in the present embodiment, the imaging device (camera 100) can be attached to and detached from the accessory 200, and includes a first control unit (camera control circuit A 101) and a second control unit (camera control circuit B 102). The first control unit can communicate with the accessory by a first communication method, and the second control unit can communicate with the accessory by a second communication method. The first control unit obtains control information related to the second communication method from the accessory. The second control unit determines the control method for communicating with the accessory based on the control information obtained by the first control unit. The first control unit and the second control unit can be configured as an integrated control unit.

[0255] In the present embodiment, the accessory 200 can be attached to and detached from the imaging device (camera 100), and includes a control unit (accessory control circuit 201) that can communicate with the imaging device by a first communication method and a second communication method. The control unit sends control information related to the second communication method to the imaging device by the first communication method, and communicates with the imaging device by the second communication method according to the control method determined by the imaging device based on this control information.

[0256] The second communication method can provide communication at a communication speed higher than that of the first communication method. The first communication method can be an I2C communication method including two signals (i.e., a clock signal (SCL) and a data signal (SDA)). The second communication method can be an SPI communication method including a clock signal (SCLK), a chip select (CS) signal, a master output signal (MOSI), and a master input signal (MISO).

[0257] The control method determined based on the control information can include a first control method that provides communication without confirming the communicable state of the accessory, and a second control method that provides communication after confirming the communicable state of the accessory. The second control unit can communicate with the accessory by the first control method or the second control method determined based on the control information. The second control method can be a control method for determining whether the accessory is in a communicable state by the second communication method based on the level (potential level) of the master input signal.

[0258] The control information can include information indicating the transmission interval of communication data by the first control method. The control information can include information indicating the mode (operation mode) of the accessory.

[0259] In each of the above embodiments, the accessory 200 is directly attached to the camera 100, but another implementation can also be used. For example, the camera 100 and the main accessory corresponding to the accessory 200 can communicate with each other via an intermediate accessory (such as an adapter device attached to the camera 100) and the main accessory. In this implementation, the intermediate accessory can perform at least a part of the communication control similar to the communication control performed by the accessory 200 and the communication control performed by the camera 100 in the above embodiments. The intermediate accessory can be used as an information transmission path such that the accessory outputs information corresponding to the information input from the camera 100 to the main accessory, and the main accessory outputs information corresponding to the input information to the camera 100. Therefore, the accessory according to the present invention includes various accessories such as a microphone device, a lighting device, and an adapter device. In addition, the adapter device can also be included in the electronic device.

[0260] Each of the above embodiments can provide an electronic device, a control method of the electronic device, an accessory, and a control method of the accessory, each of which can enhance the responsiveness at startup in a system where the accessory is attached to the electronic device.

[0261] Other embodiments

[0262] Embodiments of the present invention can also be implemented by the following method, that is, software (program) that executes the functions of the above embodiments is provided 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.

[0263] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims is to be accorded the broadest interpretation so as to encompass all such modifications, equivalent structures and functions.

Claims

1. A camera device that can be attached to an accessory and detached from the accessory, the camera device comprises: a first control unit capable of communicating with the accessory by a first communication method; and a second control unit capable of communicating with the accessory by a second communication method, characterized in that the first control unit obtains control information related to the second communication method from the accessory, wherein the second control unit determines a control method for communicating with the accessory based on the control information obtained by the first control unit, wherein the control method includes: a first control method for communicating without checking whether the accessory can communicate; and a second control method for communicating after checking whether the accessory can communicate, wherein the second control unit communicates with the accessory by the first control method or the second control method determined based on the control information.

2. The camera device according to claim 1, characterized in that the second communication method has a higher communication speed than the first communication method.

3. The camera device according to claim 1, characterized in that the first communication method is an I2C communication method including a clock signal and a data signal.

4. The camera device according to claim 1, characterized in that the second communication method is an SPI communication method including a clock signal, a chip select signal, a master output signal, and a master input signal.

5. The camera device according to claim 1, characterized in that the second control method is a control method for determining information related to whether communication with the accessory can be performed by the second communication method based on the level of the master input signal.

6. The camera device according to claim 1, characterized in that the control information includes information indicating the transmission interval between communication data in the first control method.

7. The camera device according to any one of claims 1 to 6, characterized in that the control information includes information indicating the mode of the accessory.

8. An accessory that can be attached to a camera device and detached from the camera device, the accessory comprises: a control unit capable of communicating with the camera device by a first communication method and a second communication method, characterized in that the control unit: sends control information related to the second communication method to the camera device by the first communication method, and communicates with the camera device by the second communication method according to the control method determined by the camera device based on the control information, wherein the control method includes: a first control method for communicating without checking whether the accessory can communicate; and a second control method for communicating after checking whether the accessory can communicate, wherein the control unit communicates with the camera device by the first control method or the second control method determined based on the control information.

9. The accessory according to claim 8, characterized in that The second communication method has a communication speed higher than that of the first communication method.

10. The accessory according to claim 8, wherein, the first communication method is an I2C communication method including a clock signal and a data signal.

11. The accessory according to claim 8, wherein, the second communication method is an SPI communication method including a clock signal, a chip select signal, a master device output signal, and a master device input signal.

12. The accessory according to claim 8, wherein, the second control method is a control method for determining information related to whether the accessory can communicate via the second communication method based on the level of the master device input signal.

13. The accessory according to claim 8, wherein, the control information includes information indicating the transmission interval between communication data in the first control method.

14. The accessory according to any one of claims 8 to 13, wherein, the control information includes information indicating the mode of the accessory.

15. A control method for a camera device that can be attached to and detached from an accessory, the control method comprising the following steps: obtaining control information related to a second communication method from the accessory via a first communication method; determining a control method for communicating with the accessory via the second communication method based on the control information; and communicating with the accessory via the second communication method according to the control method for communicating with the accessory, wherein the control method for communicating with the accessory includes: a first control method for communicating without checking whether the accessory can communicate; and a second control method for communicating after checking whether the accessory can communicate, wherein communication with the accessory is performed via the first control method or the second control method determined based on the control information.

16. A control method for an accessory that can be attached to and detached from a camera device, the control method comprising the following steps: sending control information related to a second communication method to the camera device via a first communication method; and communicating with the camera device via the second communication method according to the control method determined by the camera device based on the control information, wherein the control method determined based on the control information includes: a first control method for communicating without checking whether the accessory can communicate; and a second control method for communicating after checking whether the accessory can communicate, wherein communication with the camera device is performed via the first control method or the second control method determined based on the control information.

17. A non-transitory computer-readable storage medium storing a program for causing a computer of a camera device to execute the control method according to claim 15.

18. A non-transitory computer-readable storage medium stores a program for causing a computer of an accessory to execute the control method according to claim 16.

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