Electronic equipment and accessories

Abstract

To improve responsiveness at startup in a system in which an accessory is attached to an electronic device. [Solution] An electronic device (100) has a first processing means (101) capable of communicating with an accessory (200) using a first communication method, and a second processing means (102) capable of communicating with the accessory using a second communication method different from the first communication method. In response to detecting that the accessory has been attached to the electronic device, the first processing means receives accessory information from the accessory using the first communication method to identify the accessory, and then notifies the second processing means of the accessory information. Based on the notified accessory information, the second processing means communicates with the accessory using the second communication method to control the accessory.

Description

Technical Field

[0006] ,

[0001] The present invention relates to an electronic device such as an imaging device to which an accessory can be attached.

Background Art

[0002] When an imaging device is activated (powered on) in an imaging system in which an accessory such as a lighting device is attached to the imaging device, the imaging device generally detects the attachment of the accessory by switch detection or communication detection after the activation is completed, and then acquires necessary information from the accessory. Patent Document 1 discloses an imaging device that acquires specific information from an accessory having a display function and then instructs information to be displayed on the accessory.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The imaging device may be activated from a state where communication with the accessory is impossible, such as a power-off state or a low-power (sleep) state. However, if the imaging device can only acquire information from the accessory after it has been fully activated, it takes time to acquire the information necessary for controlling the accessory. In particular, when the imaging device makes a control-related determination using information from the accessory, the responsiveness of the imaging system is impaired by the above-mentioned time.

[0005] The present invention provides an electronic device and an accessory capable of enhancing the responsiveness at startup in a system in which an accessory is attached to an electronic device.

Means for Solving the Problems

[0006] One aspect of the present invention is an electronic device to which an accessory is detachably attached. The electronic device has a first processing means capable of communicating with the accessory using a first communication method, and a second processing means capable of communicating with the accessory using a second communication method different from the first communication method. The electronic device has a first power state in which it is capable of communicating with the accessory, and a second power state in which it consumes less power than the first power state. The first processing means is comprised of a processor that operates at lower power than the processor comprising the second processing means. The first processing means communicates with the accessory using a first communication method in a first power state and a second power state, and the second processing means communicates with the accessory using a second communication method in the first power state and does not send or receive information with the accessory using the second communication method in the second power state, characterized in that the contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different. A system having the above-mentioned electronic device and an accessory detachably attached thereto also constitutes another aspect of the present invention.

[0007] Furthermore, an accessory, as another aspect of the present invention, is detachably attached to an electronic device. The accessory has an accessory processing means capable of communicating with the electronic device using a first communication method and a second communication method different from the first communication method. The accessory processing means communicates with the electronic device using the first communication method in a first power state in which it is capable of communicating with the accessory and in a second power state in which the power consumption is lower than that of the first power state, the electronic device communicates with the electronic device using the second communication method in the first power state, and the electronic device does not send or receive information to or from the electronic device using the second communication method in the second power state, and the contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different. The first communication method has a lower communication speed than the second communication method. It is characterized by the following.

[0008] Furthermore, another aspect of the present invention, a control method, is applied to an electronic device having an accessory that is detachably attached and comprising a first processing means and a second processing means. The electronic device has a first power state in which it is in a state in which it can communicate with the accessory, and a second power state in which it consumes less power than the first power state, and the control method provides the first processing means with a first communication means in the first power state and the second power state. formula The invention is characterized in that the first processing means communicates with an accessory, and in the first power state, it communicates with the accessory using a second communication method different from the first communication method, and in the second power state, it does not send or receive information with the accessory using the second communication method, and the contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different, and the first processing means is composed of a processor that operates at lower power than the processor that constitutes the second processing means. Furthermore, a program that causes the computer of an electronic device to execute processing according to the above control method also constitutes another aspect of the present invention.

[0009] Furthermore, another aspect of the present invention, the control method, is applied to an accessory that is detachably attached to an electronic device. The control method causes the accessory to communicate with the electronic device using a first communication method in a first power state in which the accessory is capable of communicating with the accessory and in a second power state in which the power consumption is lower than that of the first power state, and causes the accessory to communicate with the electronic device using a second communication method different from the first communication method in the first power state, and does not cause the electronic device to send or receive information with the electronic device using the second communication method in the second power state, and the contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different. The first communication method has a lower communication speed than the second communication method. This is a characteristic feature. Furthermore, a program that causes the accessory's computer to execute processing according to the above control method also constitutes another aspect of the present invention. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve the responsiveness during startup in systems in which accessories are attached to electronic devices. [Brief explanation of the drawing]

[0011] [Figure 1] A diagram showing the configuration of the camera system (camera, lens unit, and accessories) in Example 1. [Figure 2] A diagram showing the SPI communication protocol in Example 1. [Figure 3]Flowchart showing the processes performed by the camera and the accessory in Example 1. [Figure 4] Diagram showing communication data in SPI communication in Example 1. [Figure 5] Diagram showing accessory information in Example 1. [Figure 6] Diagram showing the processing sequence of the camera system in Example 1. [Figure 7] Diagram showing accessory type information in Example 1. [Figure 8] Diagram showing the causes of communication requests in Example 1. [Figure 9] Diagram showing the communication interval in SPI communication in Example 1. [Figure 10] Flowchart showing the startup process performed by the camera (camera control circuit A) in Example 1. [Figure 11] Flowchart showing the startup process performed by the camera (camera control circuit B) in Example 1. [Figure 12] Flowchart showing the processes performed by the accessory in Example 1. [Figure 13] Diagram showing the startup sequence of the camera system in Example 1. [Figure 14] Diagram showing the startup sequence from the low power consumption mode in Example 2. [Figure 15] Diagram showing an example of an I2C communication waveform. [Figure 16] Diagram showing the processes performed by the camera when transmitting N bytes of data from the camera to the accessory in Example 1. [Figure 17] Diagram showing the processes performed by the camera when receiving N bytes of data from the accessory by the camera in Example 1. [Figure 18] Diagram showing the processes performed by the accessory when transmitting and receiving N bytes of data between the camera and the accessory in Example 1. [Figure 19] Flowchart showing the processes when SW1 / SW2 are turned on simultaneously in Example 3. [Figure 20]Flowchart showing the processing when SW1 / SW2 are both ON as a comparative example. [Figure 21] Flowchart showing the live view display processing in Example 4. [Figure 22] Flowchart showing the live view display processing as a comparative example.

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment

[0013] FIG. 1 shows the electrical configuration of an imaging system composed of an imaging device (hereinafter referred to as a camera) 100, which is an electronic device according to Embodiment 1 of the present invention, and an accessory 200 that is detachably attached thereto. The accessory 200 is, for example, a microphone device or a lighting (strobe or flash) device, and includes various devices that can be attached to the camera 100. The camera 100 and the accessory 200 are electrically connected by the plurality of contacts (terminals) TC01 to TC21 of the camera connection portion 141 provided in the camera 100 and the plurality of contacts TA01 to TA21 of the accessory connection portion 211 provided in the accessory 200 coming into one-to-one contact with each other. Note that the accessory 200 may not have some of the plurality of contacts TA01 to TA21.

[0014] The camera 100 is supplied with power from a battery 111. The battery 111 is detachable from the camera 100. The camera control circuit A101 as the first processing means and receiving means in the camera 100 and the camera control circuit B102 as the second processing means are circuits that control the entire camera 100, and are constituted by a processor (microcomputer) such as a CPU. The camera control circuit A101 and the camera control circuit B102 execute various controls and processes according to a computer program.

[0015] The camera control circuit A101 monitors the operation of switches and other controls for camera operation (not shown) and controls the system power supply in response to user operations. The camera control circuit A101 is composed of a low-power type processor that can operate even when the camera 100 is in a low-power mode (second power state) as a standby state. On the other hand, the camera control circuit B102 is responsible for controlling the imaging sensor 122 and the display circuit 127. The camera control circuit B102 is composed of a processor that stops operating in the low-power mode and operates in the normal operation mode (first power state).

[0016] In this embodiment, the case in which camera control circuit A101 and camera control circuit B102 are configured using separate processors is described, but they may also be provided within a single processor.

[0017] The system power supply circuit 112 is a circuit that generates the power supplied to each circuit of the camera 100, and is composed of a DC / DC converter circuit, an LDO (Low Drop Out), and a charge pump circuit, etc. The camera control circuit A101 is constantly supplied with 1.8V, a voltage generated by the system power supply circuit 112 that receives power from the battery 111, as the camera microcontroller power supply VMCU_C. In addition, the camera control circuit B102 is supplied with several types of voltages generated by the system power supply circuit 112 as the camera microcontroller power supply VMCU2_C at arbitrary timings. The camera control circuit A101 controls the on / off switching of power supply to each circuit of the camera 100 by controlling the system power supply circuit 112.

[0018] The optical lens 121 is detachable from the camera 100. Light from the subject entering through the optical lens 121 is imaged onto the image sensor 122, which is made up of a CMOS sensor, CCD sensor, or the like. The optical lens 121 and the camera 100 may be configured as an integrated unit. The subject image formed on the image sensor 122 is encoded into a digital imaging signal. The image processing circuit 123 performs image processing such as noise reduction and white balance processing on the digital imaging signal to generate image data, and converts the image data into an image file such as JPEG format for recording in the recording memory 126. The image processing circuit 123 also generates VRAM image data from the image data for display on the display circuit 127.

[0019] The memory control circuit 124 controls the transmission and reception of image data and other data generated by the image processing circuit 123, etc. The volatile memory 125 is a high-speed read and write memory such as DDR3 SDRAM, and is used as a workspace for image processing performed by the image processing circuit 123. The recording memory 126 is a read / write recording medium such as an SD card or 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 located on the back of the camera 100 and is composed of an LCD panel or an organic EL display panel, etc. The backlight circuit 128 adjusts the brightness of the display circuit 127 by changing the light intensity of the backlight of the display circuit 127.

[0020] Accessory power supply circuits A131 and B132 are voltage conversion circuits that convert the voltage supplied from the system power supply circuit 112 to a predetermined voltage. In this embodiment, they generate 3.3V as the accessory power supply VACC. However, configurations that convert to other voltages are also possible.

[0021] The accessory power supply circuit A131 is a power supply circuit with low self-power consumption, consisting of an LDO, etc. The accessory power supply circuit B132 is a circuit consisting of a DC / DC converter circuit, etc., and can supply a larger current than the accessory power supply circuit A131. However, the self-power consumption of the accessory power supply circuit B132 is greater than that of the accessory power supply circuit A131. Therefore, when the load current is small, the accessory power supply circuit A131 is more efficient than the accessory power supply circuit B132, and when the load current is large, the accessory power supply circuit B132 is more efficient than the accessory power supply circuit A131. The camera control circuit A101 controls the on / off switching of the voltage output of the accessory power supply circuit A131 and the accessory power supply circuit B132 according to the operating state of the accessory 200.

[0022] The protection circuit 133 is composed of a current fuse element, a polyswitch element, or an electronic fuse circuit combining a resistor, amplifier, and switch element. The protection circuit 133 outputs an overcurrent detection signal DET_OVC when the power supply current value supplied to the accessory 200 from the accessory power supply circuit A131 and accessory power supply circuit B132 exceeds a predetermined value and becomes excessive (abnormal). In this embodiment, the protection circuit 133 is an electronic fuse circuit and notifies the camera control circuit A101 with an overcurrent detection signal DET_OVC when a current of 1A or more flows. The overcurrent detection signal DET_OVC indicates an overcurrent by being at a Hi level. Note that the predetermined value may be different from 1A.

[0023] The camera connection section 141 is a connector for making an electrical connection to the accessory 200 via 21 contacts TC01 to TC21 arranged in a row. The contacts TC01 to TC21 are arranged in this order from one end to the other in the direction of their arrangement.

[0024] TC01 is connected to ground (GND) and serves not only as a reference potential contact but also as a contact that controls the wiring impedance of differential signals D1N and D1P. TC01 corresponds to a third ground contact.

[0025] The differential signal D1N connected to TC02 and the differential signal D1P connected to TC03 are differential data communication signals that work together as a pair for data communication, and are connected to the camera control circuit B102. TC02, TC03, and TC07-TCA10, TC12-TC17, TC19, and TC20 (described later) are communication contacts.

[0026] TC04, acting as the first ground contact, is connected to GND and serves as the reference potential contact for camera 100 and accessory 200. TC04 is positioned further outward in the contact arrangement direction than TC05, which will be described next.

[0027] The accessory power supply (output signal) VACC, generated by the accessory power supply circuits A131 and B132, is connected to TC05, which acts as a power supply contact, via the protection circuit 133.

[0028] The accessory mounting detection signal (first input signal) / ACC_DET is connected to TC06, which serves as the mounting detection contact. The accessory mounting detection signal / ACC_DET is pulled up to the camera microcontroller power supply VMCU_C via a resistor Rp134 (e.g., 10kΩ). The camera control circuit A101 can detect whether accessory 200 is mounted by reading the signal level of the accessory mounting detection signal / ACC_DET. If the signal level (potential) of accessory mounting detection signal / ACC_DET is at a Hi level (predetermined potential), it is detected that accessory 200 is not mounted, and if it is at a Lo level (GND potential) as the active potential, it is detected that accessory 200 is mounted.

[0029] When the camera 100 is powered on, the signal level (potential) of the accessory installation detection signal / ACC_DET changes from a high level to a low level, which triggers various communications between the camera 100 and the accessory 200 via contacts.

[0030] The camera control circuit 101 detects that the accessory 200 is attached and supplies power to the accessory 200 via the TC05, which acts as a power contact.

[0031] The SCLK connected to the communication contact TC07, the MOSI connected to TC08, the MISO connected to TC09, and the CS connected to TC10 are signals for the camera control circuit B102 to act as the communication master and perform communication using the second communication method, SPI (Serial Peripheral Interface) communication method (hereinafter referred to as SPI communication). SCLK is the clock signal, MOSI is the transmit signal, MISO is the receive signal, and CS (Chip Select) is the communication selection signal, which is used to select the communication partner. In this embodiment, the communication clock frequency for SPI communication is 1 MHz, the data length is 8 bits (1 byte), the bit order is MSB first, and it is a full-duplex communication method.

[0032] In this embodiment, the camera 100 and accessory 200 can support two types of communication protocols as SPI communication methods. Communication protocol A is a communication method in which the camera 100 does not check whether the accessory 200 is in a communication-ready state before outputting SCLK, and will be referred to as SPI protocol A in the following description. Figure 2(a) shows a schematic of the communication waveform of SPI protocol A. In the figure, CS is set to Lo active.

[0033] The camera control circuit B102 changes CS to a Lo level (active) at timing A1 and requests SPI communication from the accessory control circuit 201.

[0034] At timing A2, a predetermined time T_CS after timing A1, the camera control circuit B102 starts outputting SCLK and MOSI. Additionally, when the accessory control circuit 201 detects a falling edge change in SCLK, it starts outputting MISO.

[0035] The camera control circuit B102 stops outputting SCLK at timing A3, when the output of one byte of SCLK has been completed.

[0036] Furthermore, the camera control circuit B102 stops the output of SCLK from timing A3 until a predetermined time T_INTERVAL has elapsed, and then resumes the output of SCLK at timing A4 after T_INTERVAL has elapsed to perform the next 1-byte communication.

[0037] The flowchart in Figure 3(a) shows the processing performed by the camera control circuit B102 in SPI protocol A. S stands for step.

[0038] In S101, the camera control circuit B102 stores a numerical value indicating the number of bytes to communicate in its internal variable N. For example, if 3 bytes are to be communicated, it stores 3.

[0039] In S102, the camera control circuit B102 changes CS to a low level to request SPI communication.

[0040] In S103, the camera control circuit B102 changes CS to a low level and then performs a wait process until a predetermined time T_CS has elapsed. After the predetermined time T_CS has elapsed, the process proceeds to S104.

[0041] In S104, the camera control circuit B102 controls the output of SCLK, as well as the output of MOSI data and the input of MISO data, in order to communicate 1-byte data.

[0042] In S105, the camera control circuit B102 checks whether the internal variable N, which indicates the number of communication bytes, is 0. If the internal variable N is 0, the process proceeds to S106; otherwise, the process proceeds to S107.

[0043] In S107, the camera control circuit B102 stores a new internal variable N, which is the value obtained by subtracting 1 from the value of the internal variable N that indicates the number of communication bytes.

[0044] In S108, the camera control circuit B102 waits until a predetermined time T_INTERVAL has elapsed since the completion of 1-byte data communication in S104. After the predetermined time T_INTERVAL has elapsed, it returns to the process in S104 and executes the same process again.

[0045] In S106, the camera control circuit B102 changes CS to a high level, ending the series of SPI communications.

[0046] The flowchart in Figure 3(b) shows the processing performed by the accessory control circuit 201 in SPI protocol A.

[0047] In S201, the accessory control circuit 201 checks whether CS has changed to Lo. If CS has changed to Lo, the process proceeds to S202; otherwise, it returns to S211.

[0048] In S202, the accessory control circuit 201 performs 1-byte data communication by controlling the input of MOSI data and the output of MISO data in response to the input of the SCLK signal.

[0049] In S203, the accessory control circuit 201 checks whether CS has changed to Hi. If CS has changed to Hi, it determines that SPI communication has ended; if CS has not changed to Hi, it returns to S202 to perform the next 1-byte communication.

[0050] Furthermore, communication protocol B in the SPI communication method is a communication method in which camera 100 checks whether accessory 200 is in a communication-ready state before outputting SCLK, and will be referred to as SPI protocol B in the following explanation. Figure 2(b) shows a schematic of the communication waveform of SPI protocol B.

[0051] The camera control circuit B102 changes CS to a low level at timing B1 and requests SPI communication from the accessory control circuit 201. In addition to requesting communication, the camera control circuit B102 also checks the potential of MISO. If MISO is at a high level, it is determined that the accessory control circuit 201 is ready to communicate; if it is at a low level, it is determined that the accessory control circuit 201 is not ready to communicate.

[0052] On the other hand, when the accessory control circuit 201 detects the falling edge of CS at timing B2, it controls MISO to a high level if SPI communication is possible, and controls MISO to a low level if communication is not possible.

[0053] Furthermore, when the camera control circuit B102 confirms that MISO is at a high level at timing B3, it starts outputting SCLK and MOSI. Also, when the accessory control circuit 201 detects a falling edge change in SCLK, it starts outputting MISO.

[0054] The camera control circuit B102 stops outputting SCLK when it has completed outputting one byte of SCLK at timing B4.

[0055] After sending and receiving one byte of data, the accessory control circuit 201 controls MISO to a high level if SPI communication is possible, and to a low level if SPI communication is not possible, as shown in timings B5 and B6.

[0056] The camera control circuit B102 checks 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 state where communication is possible; if it is at a low level, it is determined that the accessory control circuit 201 is in a state where communication is not possible.

[0057] The flowchart in Figure 3(c) shows the processing performed by the camera control circuit B102 in SPI protocol B.

[0058] In S111, the camera control circuit B102 stores a numerical value indicating the number of bytes to communicate in its internal variable N. For example, if 3 bytes are to be communicated, it stores 3.

[0059] In S112, the camera control circuit B102 changes CS to a low level to request SPI communication.

[0060] In S113, the camera control circuit B102 checks whether the MISO has changed to a Hi level. If the MISO is at a Hi level, the process proceeds to S114; otherwise, it returns to S113.

[0061] In S114, the camera control circuit B102 controls the output of SCLK, as well as the output of MOSI data and the input of MISO data, in order to communicate 1-byte data.

[0062] In S115, the camera control circuit B102 checks whether all data communication is complete (i.e., the internal variable N, which indicates the number of bytes communicated, is 0). If the internal variable N is 0, the process proceeds to S116; otherwise, the process proceeds to S117.

[0063] In S117, the camera control circuit B102 stores a new internal variable N, which is the value obtained by subtracting 1 from the value of the internal variable N that indicates the number of communication bytes.

[0064] In S118, the camera control circuit B102 checks whether the MISO has changed to a Hi level. If the MISO is at a Hi level, the process proceeds to S114; otherwise, it returns to S118.

[0065] In S116, the camera control circuit B102 changes CS to a high level, ending the series of SPI communications.

[0066] The flowchart in Figure 3(d) shows the processing performed by the accessory control circuit 201 in SPI protocol B.

[0067] In S211, the accessory control circuit 201 checks whether CS has changed to Lo. If CS has changed to Lo, the process proceeds to S212; otherwise, it returns to S211.

[0068] In S212, the accessory control circuit 201 checks whether it is capable of SPI communication. If SPI communication is possible, the process proceeds to S213; otherwise, it proceeds to S214.

[0069] In S213, the accessory control circuit 201 controls MISO to a high level and proceeds to S215.

[0070] In S214, the accessory control circuit 201 controls MISO to a low level and returns to S212.

[0071] In S215, the accessory control circuit 201 performs 1-byte data communication by controlling the input of MOSI data and the output of MISO data in response to the SCLK signal input.

[0072] In S216, the accessory control circuit 201 checks whether CS has changed to Hi. If CS has changed to Hi, it determines that SPI communication has ended; if CS has not changed to Hi, it returns to S212 to perform the next 1-byte communication.

[0073] Figure 4 shows the communication content when an operation execution command is sent from the camera 100 to the accessory 200 via SPI communication in this embodiment.

[0074] In the first byte of communication, the camera control circuit B102 sends information CMD, indicating the command number, as MOSI data to the accessory control circuit 201. The accessory control circuit 201 sends the value 0xA5, which indicates that communication is possible, as MISO data to the camera control circuit B102. If the accessory control circuit 201 is unable to perform the first byte of communication processing, it sends a value other than 0xA5 as MISO data to the camera control circuit B102.

[0075] In the second byte of communication, the camera control circuit B102 sends the argument MOSI_DATA1, corresponding to the command number CMD, to the accessory control circuit 201. Similarly, from the third byte onward (N-2) bytes, it sends the arguments MOSI_DATA2 to MOSI_DATA[N-3], corresponding to the command number CMD, to the accessory control circuit 201.

[0076] In the second byte of communication, the accessory control circuit 201 sends the command number CMD received in the first byte as MISO data to the camera control circuit B102. This allows the camera control circuit B102 to determine that the accessory control circuit 201 has correctly received the MOSI data.

[0077] Furthermore, in the third byte of communication, the accessory control circuit 201 sends the return value MISO_DATA1, corresponding to the command number CMD, as MISO data to the camera control circuit B102. Then, from the fourth byte onward (N-2) bytes, it similarly sends the arguments MISO_DATA2~MISO_DATA[N-4], corresponding to the command number CMD, to the camera control circuit B102.

[0078] The number of arguments and return values ​​is predetermined for each command number. Furthermore, either an argument or a return value, or both, may be omitted.

[0079] The camera control circuit B102 sends the checksum data CheckSum_C as MOSI data to the accessory control circuit 201 during the (N-1)th byte of communication. The checksum data CheckSum_C is a value calculated using the following formula. CheckSum_C=EXOR(AND( SUM(CMD, MOSI_DATA1, …, MOSI_DATA[N-3]), 0xFF ), 0xFF ) Additionally, the accessory control circuit 201 transmits 0x00 as MISO data.

[0080] Next, in the Nth byte of communication, the camera control circuit B102 sends 0x00 as MOSI data to the accessory control circuit 201.

[0081] Furthermore, the accessory control circuit 201 transmits checksum data CheckSum_A as MISO data. The checksum data CheckSum_A is calculated using the following formula if the value of CheckSum_C received by the camera control circuit B102 in the (N-1)th byte of communication matches the value of CheckSum_C calculated by the camera control circuit B102. CheckSum_A=EXOR(AND(SUM(0xA5, CMD,MIS0_DATA1,…, MOSI_DATA[N-4]), 0xFF ), 0xFF ) On the other hand, if the value of CheckSum_C received by the camera control circuit B102 in the (N-1)th byte of communication does not match the value of CheckSum_C calculated by the camera control circuit B102, it is calculated using the following formula. CheckSum_A=AND(SUM(0xA5, CMD, MIS0_DATA1, …, MOSI_DATA[N-4] ), 0xFF ) The signal contact (communication request contact) TC11 shown in Figure 1 is connected to a communication request signal (second input signal) / WAKE, which is used by accessory 200 to request communication from camera 100 (camera control circuit A101). The communication request signal / WAKE is pulled up to the camera microcontroller power supply VMCU_C via a resistor. The camera control circuit A101 can detect the communication request from accessory 200 by detecting the change (falling edge) of the communication request signal / WAKE.

[0082] SDA, connected to the communication contact TC12, and SCL, connected to TC13, are signals for the camera control circuit A101 to act as the communication master and perform communication using the first communication method, I2C (Inter-Integrated Circuit) communication method (hereinafter referred to as I2C communication). SDA is a data signal, and SCL is a clock signal. SDA and SCL are connected via open-drain communication pulled up to the camera microcontroller power supply VMCU_C, and in this embodiment, the communication frequency is 100kbps.

[0083] In I2C communication, both data transmission from camera 100 and data transmission from accessory 200 are performed via SDA. Comparing SPI communication and I2C communication, I2C communication is slower than SPI communication. Also, since SPI communication is faster than I2C communication, it is suitable for transmitting large amounts of data. Therefore, in the communication between camera 100 and accessory 200 in this embodiment, large amounts of data are transmitted using SPI communication, and small amounts of data are transmitted using I2C communication. For example, data is first transmitted using I2C communication, and then, based on this data, if SPI communication is possible or necessary, it can be controlled to execute SPI communication.

[0084] Figures 15(a) and (b) show examples of I2C communication waveforms. Figure 15(a) shows an example waveform when the camera sends N bytes of data (DATA[1] to DATA[N]) to the accessory, and Figure 15(b) shows an example waveform when the camera receives N bytes of data (DATA[1] to DATA[N]) from the accessory. In Figures 15(a) and 15(b), the upper waveform is SCL, and the lower waveform is SDA.

[0085] Below the SDA waveform, the meaning of the signal at each timing point and whether the control circuit controlling the output level of the SDA signal is the camera control circuit A101 or the accessory control circuit 201 are indicated. Furthermore, the communication data consists of 1-byte data and 1-bit information indicating the response. The top of the diagram shows which byte of data it is from the start of communication.

[0086] Details of the communication content will be described later using Figures 16-18, so Figures 15(a) and 15(b) will only provide an overview.

[0087] In Figure 15(a), during the first and second byte communications, the camera control circuit A101 notifies the accessory control circuit 201 of the storage address information of the data to be transmitted. During the third to (N+2) byte communications, the camera control circuit A101 transmits N bytes of data (DATA[ADDRESS]~DATA[ADDRESS+N]) to the accessory control circuit 201.

[0088] In Figure 15(b), during the first and second bytes of communication, the camera control circuit A101 notifies the accessory control circuit 201 of the storage address information of the data to be received. During the third to (N+3)th byte of communication, the camera control circuit A101 receives N bytes of data (DATA[ADDRESS]~DATA[ADDRESS+N]) from the accessory control circuit 201.

[0089] The flowchart in Figure 16 shows the process that camera control circuit A101 performs when it sends N bytes of data from camera control circuit A101 to accessory control circuit 201.

[0090] In S3001, the camera control circuit A101 stores a numerical value indicating the number of bytes to be transmitted in the internal variable N. For example, if 3 bytes are to be transmitted, 3 is stored. In this embodiment, 3 is stored.

[0091] In S3002, the camera control circuit A101 changes SDA to a low level (START condition) while SCL is at a high level. This notifies the accessory control circuit 201 to start communication.

[0092] In S3003, the camera control circuit A101 sets the slave address information, which indicates the slave address of the accessory control circuit 201, in the upper 7 bits of the transmitted data. In this embodiment, the slave address of the accessory control circuit 201 is assumed to be 1010000 in binary.

[0093] In S3004, the camera control circuit A101 sets information indicating that it is a WRITE communication in the lower 1 bit of the transmitted data. Setting this bit to 0 means it is a WRITE communication.

[0094] In S3005, the camera control circuit A101 transmits the data (10100000 in binary, 0xA0 in hexadecimal) that was set as the data to be transmitted in S3003 and S3004 to the accessory control circuit 201.

[0095] In S3006, the camera control circuit A101 outputs SCL for one clock cycle after transmitting one byte of data and checks the signal level of SDA. If the SDA signal level is low, it is determined to be a data reception notification (ACK) from the accessory control circuit 201 and the process proceeds to S3007. On the other hand, if the SDA signal level is high, it is determined that the accessory control circuit 201 has not received the data properly and the process proceeds to S3014.

[0096] In S3007, the camera control circuit A101 sets the data storage address information (start address information) to be sent to the accessory control circuit 201 as the data to be transmitted. In this embodiment, the size of the start address information is 1 byte and the value is 0x00.

[0097] In S3008, the camera control circuit A101 transmits the set 1-byte start address information (value 0x00) to the accessory control circuit 201.

[0098] In S3009, the camera control circuit A101 outputs SCL for one clock cycle after transmitting one byte of start address information data, and checks the signal level of SDA. If the SDA signal level is low, it is determined to be a data reception notification (ACK) from the accessory control circuit 201, and the process proceeds to S3010. On the other hand, if the SDA signal level is high, it is determined that the accessory control circuit 201 has not received the data properly, and the process proceeds to S3014.

[0099] In S3010, the camera control circuit A101 stores 1 in the internal variable M. The internal variable M is a variable used to count the number of transmitted data.

[0100] In S3011, the camera control circuit A101 outputs one byte of SCL and, while SCL is low, changes SDA to a desired signal level, thereby sending one byte of data to the accessory control circuit 201. Here, the starting address information is 0x00 and the internal variable M is 1, so one byte of data corresponding to address 0x00 is sent.

[0101] In S3012, the camera control circuit A101 outputs SCL for one clock cycle after transmitting one byte of data and checks the signal level of SDA. If the SDA signal level is low, it is determined to be a data reception notification (ACK) from the accessory control circuit 201 and proceeds to S3013. On the other hand, if the SDA signal level is high, it is determined that the accessory control circuit 201 has not received the data properly and proceeds to S3014.

[0102] In S3013, the camera control circuit A101 checks if the internal variable M has the same value as the internal variable N. If the internal variable M has the same value as the internal variable N, it determines that all data transmission is complete and proceeds to S3014. If the internal variable M does not have the same value as the internal variable N, it determines that there is still data to transmit and proceeds to S3015.

[0103] In S3015, the camera control circuit A101 adds 1 to the internal variable M and returns to S3011.

[0104] In this way, after returning to S3011, the camera control circuit A101 sequentially increments the address of the data to be transmitted and transmits 1 byte of data corresponding to each address. By repeatedly transmitting 1 byte of data in this way until the internal variables M and N have the same value in the S3013 process, the camera control circuit A101 transmits N bytes of data to the accessory control circuit 201. In this embodiment, if the internal variable N is set to 3, 3 bytes of data can be transmitted.

[0105] In S3014, the camera control circuit A101 changes SDA to a high level (STOP condition) while SCL is at a high level. This notifies the accessory control circuit 201 that communication has ended.

[0106] The flowchart in Figure 17 shows the process that camera control circuit A101 performs when it receives N bytes of data from accessory control circuit 201.

[0107] In S3101, the camera control circuit A101 stores a numerical value indicating the number of bytes to be received in the internal variable N. For example, if 3 bytes are received, 3 is stored. In this embodiment, 3 is stored.

[0108] In sections S3102 to S3106, the camera control circuit A101 performs the same processing as in sections S3002 to S3006, so the explanation is omitted.

[0109] In S3107, the camera control circuit A101 sets the data storage address information (start address information) received from the accessory control circuit 201 as transmission data. In this embodiment, the size of the start address information is 1 byte, and its value is 0x00.

[0110] In S3108, the camera control circuit A101 transmits the set 1-byte start address information (value 0x00) to the accessory control circuit 201.

[0111] In S3109, the camera control circuit A101 outputs SCL for one clock cycle after transmitting one byte of start address information data, and checks the signal level of SDA. If the SDA signal level is low, it is determined to be a data reception notification (ACK) from the accessory control circuit 201, and the process proceeds to S3110. On the other hand, if the SDA signal level is high, it is determined that the accessory control circuit 201 has not received the data properly, and the process proceeds to S3122.

[0112] In S3110, the camera control circuit A101, similar to S3102, changes SDA to a low level while SCL is at a high level, and notifies the accessory control circuit 201 of the START condition.

[0113] In S3111, the camera control circuit A101 sets the slave address information, which indicates the slave address of the accessory control circuit 201, in the upper 7 bits of the transmitted data. In this embodiment, the slave address of the accessory control circuit 201 is assumed to be 1010000 in binary.

[0114] In S3112, the camera control circuit A101 sets information indicating that it is a READ communication in the lower 1 bit of the transmitted data. Setting this bit to 1 means it is a READ communication.

[0115] In S3113, the camera control circuit A101 transmits the data (10100001 in binary, 0xA1 in hexadecimal) that was set as the data to be transmitted in S3003 and S3004 to the accessory control circuit 201.

[0116] In S3114, the camera control circuit A101 outputs SCL for one clock cycle after transmitting one byte of data and checks the signal level of SDA. If the SDA signal level is low, it is determined to be a data reception notification (ACK) from the accessory control circuit 201 and the process proceeds to S3115. On the other hand, if the SDA signal level is high, it is determined that the accessory control circuit 201 has not received the data properly and the process proceeds to S3122.

[0117] In S3115, the camera control circuit A101 stores 1 in the internal variable M. The internal variable M is a variable used to count the number of received data.

[0118] In S3116, the camera control circuit A101 outputs one byte of SCL and reads the SDA signal level at the moment SCL changes from Lo to Hi. This makes it possible to receive one byte of data from the accessory control circuit 201. The received one byte of data can be stored in the volatile memory 125 as data corresponding to address 0x00 or used for predetermined processing.

[0119] In S3117, the camera control circuit A101 determines whether it has successfully received 1 byte of data. If it has been successfully received, it proceeds to S3118. If it has not been successfully received, it proceeds to S3119.

[0120] In S3118, the camera control circuit A101 checks if the internal variable M has the same value as the internal variable N. If the internal variable M has the same value as the internal variable N, it determines that all data has been received and proceeds to S3119. If the internal variable M does not have the same value as the internal variable N, it determines that there is still data to be received and proceeds to S3120.

[0121] In S3120, the camera control circuit A101 outputs one byte of SCL and controls SDA to a low level, thereby sending a data reception notification (ACK) to the accessory control circuit 201 and informing it that data communication will continue.

[0122] In S3121, the camera control circuit A101 adds 1 to the internal variable M and returns to S3116.

[0123] In this way, after returning to S3116, the camera control circuit A101 sequentially increments the address of the data to be received and receives 1 byte of data corresponding to each address. By repeatedly receiving 1 byte of data in this way until the internal variables M and N have the same value in the process of S3118, the camera control circuit A101 receives N bytes of data from the accessory control circuit 201. In this embodiment, if the internal variable N is set to 3, 3 bytes of data can be received.

[0124] In S3119, the camera control circuit A101 outputs one byte of SCL and controls SDA to a high level to notify the accessory control circuit 201 that data communication is complete (NACK).

[0125] In S3122, the camera control circuit A101 changes SDA to a high level (STOP condition) while SCL is at a high level. This notifies the accessory control circuit 201 that communication has ended.

[0126] The flowchart in Figure 18 shows the processes that the accessory control circuit 201 performs when the camera control circuit A101 sends N bytes of data to the accessory control circuit 201 and when the camera control circuit A101 receives N bytes of data from the accessory control circuit 201.

[0127] In S3201, the accessory control circuit 201 waits for SDA to change to a low level (START condition) while SCL is at a high level. Once the accessory control circuit 201 detects the START condition, it proceeds to S3202.

[0128] In 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 and received data.

[0129] In S3203, the accessory control circuit 201 receives 1 byte of data transmitted from the camera control circuit A101.

[0130] In S3204, the accessory control circuit 201 determines whether the upper 7 bits of the 1-byte data received in S3203 match the slave address of the accessory control circuit 201 (0x50 in this embodiment). If it matches the slave address of the accessory control circuit 201, the process proceeds to S3205. If it does not match the slave address of the accessory control circuit 201, the process proceeds to S3221.

[0131] In S3205, the accessory control circuit 201 notifies the camera control circuit A101 of data reception (ACK) by controlling the SDA to a low level for the next SCL clock output after receiving one byte.

[0132] In S3206, the accessory control circuit 201 determines the type of data to be transmitted in the next 1-byte communication based on the lower bit of the 1-byte data received in S3203. If the lower bit is 0, it determines that the data to be transmitted in the next 1-byte communication is start address information from the camera control circuit A101 to the accessory control circuit 201, and proceeds to S3207. If the lower bit is 1, it determines that the data to be transmitted in the next 1-byte communication is transmission data from the accessory control circuit 201 to the camera control circuit A101, and proceeds to S3209.

[0133] In S3207, the accessory control circuit 201 receives one byte of data transmitted from the camera control circuit A101. The received one byte of data is information indicating the address where the data to be transmitted and received in subsequent communications is stored. In this embodiment, as explained in Figures 16 and 17, the starting address information is assumed to be 0x00.

[0134] On the other hand, in S3209, the accessory control circuit 201 uses either address information that the accessory control circuit 201 has stored in advance or address information that has been previously notified by the camera control circuit A101 as the starting address information.

[0135] In S3208, if the accessory control circuit 201 determines that it has successfully received one byte of data, it proceeds to S3210. If it determines that it has not successfully received one byte of data, it proceeds to S3221.

[0136] In S3210, the accessory control circuit 201 notifies the camera control circuit A101 of data reception (ACK) by controlling the SDA to a low level for the next SCL clock output after receiving one byte of data.

[0137] In S3211, the accessory control circuit 201 checks whether SDA has changed to a low level (START condition) while SCL is at a high level. If the START condition is detected, the accessory control circuit 201 determines that the next 1 byte of data to be communicated is data to be sent from the camera control circuit A101 to the accessory control circuit 201, and that it is data indicating the slave address and communication type, and proceeds to S3212. If the START condition is not detected, the accessory control circuit 201 determines that the next 1 byte of data to be communicated is data information to be received by the accessory control circuit 201 from the camera control circuit A101, and proceeds to S3216.

[0138] In S3212, the accessory control circuit 201 receives 1 byte of data transmitted from the camera control circuit A101.

[0139] In S3213, the accessory control circuit 201 determines whether the upper 7 bits of the 1-byte data received in S3212 match the slave address of the accessory control circuit 201 (0x50 in this embodiment). If it matches the slave address of the accessory control circuit 201, the process proceeds to S3214. If it does not match the slave address of the accessory control circuit 201, the process proceeds to S3221.

[0140] In S3214, the accessory control circuit 201 determines the type of data to be transmitted in the next 1-byte communication based on the lower bit of the 1-byte data received in S3203. If the lower bit is 0, the process proceeds to S3221. If the lower bit is 1, the process determines that the data to be transmitted in the next 1-byte communication is data to be sent from the accessory control circuit 201 to the camera control circuit A101, and proceeds to S3215.

[0141] In S3215, the accessory control circuit 201 sends a data reception acknowledgment (ACK) to the camera control circuit A101 by controlling the SDA to a low level for the next SCL clock output after receiving one byte.

[0142] In S3222, the accessory control circuit 201 transmits 1 byte of data corresponding to the start address information received from the camera control circuit A101 in S3207 or the start address information determined in S3209 to the camera control circuit A101.

[0143] In S3223, the accessory control circuit 201 adds 1 to the internal variable M and proceeds to S3224.

[0144] In S3224, the accessory control circuit 201 checks the SDA signal level after transmitting one byte of data. If the SDA signal level is high, it determines that the camera control circuit A101 has notified it that it has received all the data (NACK) and proceeds to S3225. On the other hand, if the SDA signal level is high, it determines that the camera control circuit A101 is still requesting data transmission from the accessory control circuit 201 and returns to S3222. In this way, after returning to S3222, the accessory control circuit 201 sequentially increments the address of the data to be transmitted and transmits one byte of data corresponding to each address. In this way, by repeatedly transmitting one byte of data in the S3224 process until a NACK is notified from the camera control circuit A101, the accessory control circuit 201 transmits N bytes of data to the camera control circuit A101.

[0145] In 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, it terminates communication.

[0146] Meanwhile, in S3216, the accessory control circuit 201 receives one byte of data, and in S3207, this one byte of data is stored in a non-volatile memory (not shown) or used for predetermined processing as data corresponding to the start address information received from the camera control circuit A101.

[0147] In S3217, the accessory control circuit 201 adds 1 to the internal variable M and proceeds to S3218.

[0148] In S3218, if the accessory control circuit 201 determines that it has successfully received one byte of data, it proceeds to S3219. If it determines that it has not successfully received one byte of data, it proceeds to S3221.

[0149] In S3219, the accessory control circuit 201 sends a data reception acknowledgment (ACK) to the camera control circuit A101 by controlling the SDA to a low level for the next SCL clock output after receiving one byte.

[0150] In S3230, the accessory control circuit 201 checks whether it has detected a STOP condition in which SDA changes to a high level while SCL is at a high level. If the accessory control circuit 201 detects a STOP condition, it terminates communication. On the other hand, if the accessory control circuit 201 does not detect a STOP condition, it determines that the camera control circuit A101 will continue to transmit data to the accessory control circuit 201 and returns to S3216.

[0151] In this way, after returning to S3216, the accessory control circuit 201 sequentially increments the address of the data to be received and receives 1 byte of data corresponding to each address. By repeatedly receiving 1 byte of data in this manner until the STOP condition is notified in S3220, the accessory control circuit 201 receives N bytes of data from the camera control circuit A101.

[0152] Thus, the camera connection section 141 includes a contact TC12 for I2C communication data signals and a contact TC13 for I2C communication clock signals located on one side of the data signal contact (adjacent on one side). Furthermore, it includes a contact TC11 for a second input signal, a contact TC10 for an SPI communication input selection signal, a contact TC09 for SPI communication reception, a contact TC08 for SPI communication transmission, a contact TC07 for an SPI communication clock signal, a contact TC06 for a first input signal, and a contact TC05 for an output signal, all located on the other side of the data signal contact TC12 (in order from adjacent positions on the other side).

[0153] Accessory 200 stores accessory information in a non-volatile memory (not shown). This accessory information allows camera 100 to identify the type of accessory 200 and its specifications regarding communication and operation (function). Figure 5 shows an example of accessory information. The accessory information is mapped to a memory space at addresses 0x00 to 0x0F, and can be read from accessory 200 via I2C communication. Details of the accessory information will be described later. In this embodiment, a checksum value is added to the read data as the final data of the communication.

[0154] The FNC1 signal connected to TC14, the FNC2 signal connected to TC15, the FNC3 signal connected to TC16, and the FNC4 signal connected to TC17, which are communication contacts shown in Figure 1, are function signals whose function can be changed depending on the type of accessory 200 attached. For example, if accessory 200 is a microphone device, the signal communicated via TC15 will be a signal related to audio data, and if accessory 200 is a strobe device, the signal communicated via TC14 will be a signal that notifies the timing of the flash.

[0155] Furthermore, depending on the type of accessory installed, signals that realize different functions may be communicated via the same contact. For example, if accessory 200 is an accessory other than lighting, a synchronization signal for controlling a timing different from the light emission timing may be communicated via TC14. TC14 to TC17 correspond to function signal contacts. Communication using at least one of the function signal contacts is also called function signal communication. Function signal communication can be performed in parallel with I2C communication and SPI communication, and at a timing independent of I2C communication and SPI communication.

[0156] The accessory types referred to here are the microphone equipment, lighting equipment, etc., as described above. Accessories that perform the same function for the same purpose, such as lighting fixtures with different performance characteristics, are of the same accessory type. Accessories that perform different functions for different purposes, such as microphone equipment and lighting equipment, are of different accessory types. Functional signal communication is performed based on information obtained by I2C communication or SPI communication. TC18, which serves as a second ground contact, is also connected to GND and, like TC04, is a contact that serves as the reference potential for camera 100 and accessory 200. The differential signal D2N connected to TC19 and the differential signal D2P connected to TC20 are data communication signals that work together as a pair to perform data communication and are connected to the camera control circuit B102. It is possible to perform, for example, USB communication via TC19 and TC20.

[0157] TC21 is connected to GND and serves not only as a reference potential contact but also as a contact that controls the wiring impedance of differential signals D2N and D2P. TC21 corresponds to the fourth ground contact. Contacts TC01, TC04, TC06, TC18, and TC21 are connected, for example, to the GND portion of a flexible circuit board, and the GND portion of the flexible circuit board is fixed to a metallic component that is at the GND level of the camera 100 with screws or the like. Examples of metallic components that are at the GND level include an engagement member that engages with the accessory 200 in the accessory shoe portion, and an unillustrated base plate inside the camera 100.

[0158] In this embodiment, an accessory installation detection contact TC06, to which the accessory installation detection signal / ACC_DET is connected, is placed next to the contact TC07 (first clock contact) that transmits the 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 clock signal contact, and this can cause malfunctions. In particular, in a configuration with a large number of contacts and short distances between contacts, as in this embodiment, the effect becomes even greater. Therefore, by placing the installation detection contact TC06 next to the SCLK contact TC07, the effect of clock noise can be suppressed.

[0159] The accessory installation detection signal / ACC_DET is pulled up before the accessory is installed, but is set to GND potential after the accessory is installed. On the other hand, the SCLK contact TC07, which transmits the clock signal, does not transmit the clock signal before the accessory is installed, so there is no potential fluctuation, and the potential fluctuates only after the accessory is installed because it transmits the clock signal.

[0160] When the SCLK contact TC07 transmits the clock signal, the attachment detection contact TC06 is at GND potential. Therefore, even if the attachment detection contact TC06 is affected by clock noise, the potential of the control circuits of the camera 100 and accessory 200 is less likely to fluctuate, thus preventing malfunctions. In addition, it is possible to suppress the transmission of clock noise to locations further away from the attachment detection contact TC06. As a result, it is not necessary to provide a GND terminal, and the effects of clock noise can be suppressed without increasing the number of contacts.

[0161] Furthermore, the SCL (second clock signal) is also transmitted as a clock signal to the contact (second clock contact) TC13. However, the SCLK transmitted to the SCLK contact TC07 has a higher frequency than SCL, and therefore generates more clock noise from the SCLK contact TC07 than from the SCL contact TC13. For this reason, placing the mounting detection contact TC06 next to the SCLK contact TC07 rather than next to the SCL contact TC13 is more effective in preventing malfunctions caused by clock noise.

[0162] Furthermore, in addition to the difference in frequency, the SCL transmitted by the SCL contact TC13 is the clock signal of the I2C communication standard, and the voltage fluctuations of the signal line are driven by an open-drain connection. On the other hand, the SCLK transmitted by the SCLK contact TC07 is the clock signal of the SPI communication standard, and the voltage fluctuations of the signal line are driven by a CMOS output. For this reason, the voltage fluctuation edges of the SCL contact TC13 tend to be smoother than those of the SCLK contact TC07, and clock noise is less likely to occur. Therefore, placing the attachment detection contact TC06 next to the SCLK contact TC07 rather than next to the SCL contact TC13 is more effective in preventing malfunctions due to clock noise.

[0163] Furthermore, the first and second differential signal contacts TC19 and TC20 may also transmit differential signals D1N and D1P in pairs to transmit a clock signal. In this case, a clock signal with a higher frequency than that transmitted by the SCLK contact TC07 and SCL contact TC13 (a third clock signal) may be transmitted. However, because the differential signals D1N and D1P are paired signals, they emit less clock noise than the SCLK contact TC07 and SCL contact TC13, which transmit single-ended signals. For this reason, placing the mounting detection contact TC06 next to the SCLK contact TC07 rather than next to the first and second differential signal contacts TC19 and TC20 is more effective in preventing malfunctions due to clock noise.

[0164] Furthermore, the contact TC08 (the first data contact), located adjacent to the mounting detection contact TC06 on the opposite side of the SCLK contact TC07, transmits MOSI (the first data signal). Since MOSI is a data signal, it might seem susceptible to clock noise. However, because MOSI is a data signal using the same SPI communication standard as the clock signal transmitted by the SCLK contact TC07, the timing of its potential fluctuations is synchronized with the clock signal, making it less susceptible to clock noise. For this reason, contact TC08 does not need to be fixed to GND potential and can be used as a MOSI contact.

[0165] Accessory 200 has a battery 205 and receives power from the battery 205, as well as power from the camera 100 via the camera connection part 141 and the accessory connection part 211. The accessory control circuit 201, which serves as an accessory processing means in accessory 200, is a circuit that controls the entire accessory 200 and is composed of a processor (microcomputer) such as a CPU. The accessory control circuit 201 performs various controls and processes according to a computer program.

[0166] The accessory power supply circuit 202 is a circuit that generates power to supply each circuit of the accessory 200, and is composed of a DC / DC converter circuit, an LDO, a charge pump circuit, etc. The accessory control circuit 201 is constantly supplied with 1.8V, a voltage generated by the accessory power supply circuit 202, as the accessory microcontroller power supply VMCU_A. Note that the voltage generated by the accessory power supply circuit 202 may be a value other than 1.8V. By controlling the accessory power supply circuit 202, the on / off control of the power supply to each circuit of the accessory 200 is performed.

[0167] The charging circuit 204 is a circuit for charging the battery 205 using power supplied from the camera 100. The accessory control circuit 201 controls the charging circuit 204 to charge the battery 205 when it determines that sufficient power is being supplied from the camera 100 to perform the charging operation. In this embodiment, the case in which the battery 205 is attached to the accessory 200 is described, but the accessory 200 may operate using only power supplied from the camera 100 without the battery 205 being attached. In this case, the charging circuit 204 is not necessary.

[0168] The differential communication circuit 207 is a circuit for performing differential communication with the camera 100 and can send and receive data between it and the camera 100. The external communication IF circuit 208 is an IF circuit for performing data communication with external devices (not shown), such as an Ethernet communication IF, a wireless LAN communication IF, and a public network communication IF. The accessory control circuit 201 controls the differential communication circuit 207 and the external communication IF circuit 208, enabling it to transmit data received from the camera 100 to external devices and transmit data received from external devices to the camera 100.

[0169] The functional circuit 206 is a circuit that has different functions depending on the type of accessory 200. For example, if the accessory 200 is a strobe device, the functional circuit 206 may include a light emission circuit, a charging circuit, etc. If the accessory 200 is a microphone device, it may include an audio codec circuit, a microphone circuit, etc.

[0170] The external connection terminal 209 is a connector terminal for connecting to an external device, and in this embodiment, it is a USB TYPE-C connector. The connection detection circuit 210 is a circuit for detecting when an external device is connected to the external connection terminal 209. The accessory control circuit 201 can detect the connection of an external device to the external connection terminal 209 by receiving the output signal of the connection detection circuit 210.

[0171] The power switch 203 is a switch operated by the user to turn the power (i.e., operation) of the accessory 200 on or off. The accessory control circuit 201 can detect the on / off position by reading the signal level of the terminal to which the power switch 203 is connected.

[0172] The operation switch 212 is a switch operated by the user to give various instructions or make various settings to the accessory 200, and includes buttons, directional keys, slide switches, dial switches, touch sensors, etc. When the operation switch 212 is operated, the accessory control circuit 201 detects the operation and executes a predetermined process corresponding to the operation.

[0173] The accessory connection section 211 is a connector for making an electrical connection to the camera 100 via 21 contacts TA01 to TA21 arranged in a row. The contacts TA01 to TA21 are arranged in this order from one end to the other in the direction of their arrangement.

[0174] TA01 is connected to GND and serves not only as a reference potential contact but also as a contact that controls the wiring impedance of differential signals D1N and D1P. TA01 corresponds to a third ground contact.

[0175] The differential signal D1N connected to TA02 and the differential signal D1P connected to TA03 are data communication signals that work together as a pair to perform data communication, and are connected to the differential communication circuit 207. TA02, TA03, and TA07-TA10, TA12-17, TA19, and TA20 (described later) are communication contacts.

[0176] TA04, acting as the first ground contact, is connected to GND and serves as the reference potential contact for camera 100 and accessory 200. TA04 is positioned further outward in the contact arrangement direction than TA05, which will be described next.

[0177] The TA05, which serves as a power contact, is connected to the accessory power circuit 202 and the charging circuit 204, and the accessory power supply VAC supplied from the camera 100 is connected to it.

[0178] TA06, which acts as the attachment detection contact, is directly connected to GND. When accessory 200 is attached to camera 100, the accessory control circuit 201 sets the aforementioned accessory attachment detection signal / ACC_DET to a low level (GND potential) as the active potential. This causes camera 100 to detect that accessory 200 has been attached.

[0179] The SCLK connected to the communication contact TA07, the MOSI connected to TA08, the MISO connected to TA09, and the CS connected to TA10 are signals that enable the accessory control circuit 201 to act as a communication slave and perform SPI communication.

[0180] The TA11, which is a signal contact (communication request contact), is connected to a communication request signal / WAKE from the accessory control circuit 201 to request communication from the camera 100. When the accessory control circuit 201 determines that communication with the camera 100 is necessary, it changes the communication request signal / WAKE from a Hi level to a Lo level, thereby making a communication request to the camera 100.

[0181] When the camera control circuit 101 detects that the accessory 200 is attached and supplies power to the accessory 200 via TC5, the accessory control circuit 201 notifies the camera control circuit 101 that power has been supplied by changing the signal level (potential) of the communication request signal / WAKE from a Hi level to a Lo level.

[0182] The accessory control circuit 201 can notify the camera 100 that an event has occurred that requires the accessory 200 to communicate with the camera 100, by changing the signal level (potential) of the communication request signal / WAKE from a Hi level to a Lo level, even without a request from the camera. With this configuration, the camera control circuit 101 can omit the operation of periodically checking whether an event requiring communication has occurred by polling the accessory 200. In addition, the accessory 200 can communicate this to the camera 100 in real time when an event requiring communication occurs.

[0183] The SDA signal connected to the TA12 communication contact and the SCL signal connected to the TA13 communication contact are signals that enable the accessory control circuit 201 to act as a communication slave and perform I2C communication.

[0184] Thus, the accessory connection section 211 includes a contact TA12 for I2C communication data signals and a contact TA13 for I2C communication clock signals adjacent to the data signal contact on one side. Furthermore, it includes a contact TA11 for a second input signal, a contact TA10 for an SPI communication input selection signal, a contact TA09 for SPI communication transmission, a contact TA08 for SPI communication reception, a contact TA07 for an SPI communication clock signal, a contact TA06 for a first input signal, and a contact TA06 for an output signal, all arranged in order from a position adjacent to the data signal contact TAB12 on the other side.

[0185] The FNC1 signal connected to TA14, the FNC2 signal connected to TA15, the FNC3 signal connected to TA16, and the FNC4 signal connected to TA17, which are communication contacts (functional signal contacts), are functional signals whose function can be changed depending on the type of accessory 200. For example, if accessory 200 is a microphone device, these signals will be used for audio data, and if accessory 200 is a strobe device, these signals will be used to notify the timing of the flash.

[0186] TA18, acting as a second ground contact, is also connected to GND and, like TA04, serves as the reference potential contact for camera 100 and accessory 200. The differential signal D2N connected to TA19 and the differential signal D2P connected to TA20 are data communication signals that work together as a pair to perform data communication, and are connected to the external connection terminal 209.

[0187] TA21 is connected to GND and serves not only as a reference potential contact but also as a terminal that controls the wiring impedance of differential signals D2N and D2P. TA21 corresponds to the fourth ground contact.

[0188] Contacts TA01, TA04, TA06, TA18, and TA21 are connected, for example, to the GND portion of the flexible circuit board, and the GND portion of the flexible circuit board is fixed to a metallic component that is at the GND level of the accessory 200 with screws (not shown). The metallic component that is at the GND level may be, for example, a shoe mounting leg that engages with the accessory shoe portion of the camera 100 or a base plate (not shown) inside the accessory 200.

[0189] Figure 6 shows the sequence of processes that occur when accessory 200 is attached to camera 100. Here, we will explain the general processes of camera 100 (camera control circuits A101, B102) and accessory 200 (accessory control circuit 201), and further details will be described later.

[0190] When accessory 200 is attached to camera 100, the accessory attachment detection signal / ACC_DET becomes low. As a result, camera control circuit A101 determines that accessory 200 has been attached to camera 100. Having determined that accessory 200 has been attached, camera control circuit A101 sets the power control signal CNT_VACC1 to high in order to turn on the output of accessory power supply circuit A131. In response to the power control signal CNT_VACC1 becoming high, accessory power supply VACC is output by accessory power supply circuit A131.

[0191] The accessory power supply circuit 202, which receives power from VACC, generates power supply VMCU_A for the accessory control circuit 201. This starts up the accessory control circuit 201. The started accessory control circuit 201 initializes each block within the accessory 200. Subsequently, when the accessory control circuit 201 is ready to communicate with the camera 100, it sets the communication request signal / WAKE to a low level.

[0192] The camera control circuit A101 detects that accessory 200 is ready to communicate when the communication request signal / WAKE goes to a low level. The camera control circuit A101 requests accessory information from accessory 200 via I2C communication. Upon receiving the accessory information request, accessory control circuit 201 transmits the accessory information to camera control circuit A101. After transmitting the accessory information, accessory control circuit 201 sets the communication request signal / WAKE to a high level.

[0193] The camera control circuit A101 determines whether or not the attached accessory can be controlled based on the received accessory information. It also turns on the accessory power supply circuit B132. Then, the camera control circuit A101 performs various settings on the camera 100, and once this is complete, it notifies the camera control circuit B102 of the accessory information.

[0194] Based on the notified accessory information, the camera control circuit B102 notifies the accessory 200 of control commands via SPI communication (accessory control communication) and performs control corresponding to function signals (function signal control). In other words, it controls the accessory 200 via SPI communication.

[0195] The accessory control circuit 201 responds to control commands from the camera 100 via SPI communication and performs operations according to function signals.

[0196] Here, we will explain the accessory information illustrated in Figure 5. The D7-D0 data at address 0x00 is information indicating the type of accessory (hereinafter referred to as accessory type information). Figure 7 shows an example of accessory type information. For example, 0x81 indicates a strobe 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.

[0197] Adapter devices are intermediate accessories that are attached between the camera 100 and accessories such as strobes and microphones. Interface conversion adapter devices are adapter devices that convert the interface between the camera 100 and the accessory to ensure compatibility when the interface of the camera 100 and the accessory's interface are different. Multi-accessory connection adapter devices are adapter devices that can accommodate multiple accessories.

[0198] The D7-D0 data at address 0x01 in Figure 5 indicates the model (model number) of accessory 200. By combining this information with the accessory type information described earlier, it is possible to identify the type and model of the accessory.

[0199] The D7-D0 data at address 0x02 contains information indicating the firmware version of accessory 200.

[0200] The D7-D6 data at address 0x03 is specification information indicating whether or not accessory power supply VAC is requested to accessory 200 when the camera 100 has its power switch (not shown) turned off. If this information is 0, it indicates that no power supply is required; if it is 1, it indicates a power supply request by accessory power supply circuit A131; and if it is 2, it indicates a power supply request by accessory power supply circuit B132.

[0201] The D5-D4 data at address 0x03 is specification information (hereinafter referred to as "auto power off power supply requirement information") indicating whether or not the camera 100 requests the supply of accessory power VAC to accessory 200 when it enters a power-saving state (hereinafter referred to as "auto power off state") due to the auto power off function. The camera 100 has an auto power off function that automatically turns off the power if no operation is performed for a predetermined period of time in order to reduce power consumption. If this information is 0, it indicates that no power supply is required; if it is 1, it indicates a power supply request by accessory power supply circuit A131; and if it is 2, it indicates a power supply request by accessory power supply circuit B132.

[0202] The D3-D2 data at address 0x03 contains specification information indicating whether accessory 200 has a battery 205. A value of 0 indicates that the battery is not present, while a value of 1 indicates that the battery is present.

[0203] The D1-D0 data at address 0x03 contains specification information indicating whether or not accessory 200 has a charging function for battery 205. A value of 0 indicates that it does not have a charging function, while a value of 1 indicates that it does.

[0204] The D7-D0 data at address 0x04 is specification information indicating the power request of accessory 200 to the accessory power supply VAC supplied by camera 100. For example, multiplying this information by 10 indicates the current value; if this information is 10, it indicates 100mA, and if this information is 100, it indicates 1A. Alternatively, to reduce the amount of information, this information may be simplified and associated with the current value. For example, if this information is 0, it may indicate 100mA; if this information is 1, it may indicate 300mA; if this information is 3, it may indicate 450mA; and if this information is 4, it may indicate 600mA.

[0205] The D7 data at address 0x05 contains specification information indicating whether accessory 200 is in firmware update mode or not. A value of 0 indicates that it is not in firmware update mode, while a value of 1 indicates that it is in firmware update mode.

[0206] The D6 data at address 0x05 is specification information indicating whether or not accessory 200 has a firmware update function. If this information is 0, it indicates that it does not have a firmware update function, and if it is 1, it indicates that it does have a firmware update function.

[0207] The D5-D4 data at address 0x05 contains specification information indicating whether or not operation is permitted when accessory 200 is attached to an intermediate connection accessory. A value of 0 indicates that operation is not permitted, and a value of 1 indicates that operation is permitted.

[0208] The D3-D2 data at address 0x05 is specification information indicating whether accessory 200 requires camera 100 to confirm the attachment of the intermediate connection accessory when camera 100 is activated. If this information is 0, it indicates that confirmation is not required, and if it is 1, it indicates that confirmation is required.

[0209] The D1-D0 data at address 0x05 is specification information indicating whether accessory 200 supports command notification via I2C communication. A value of 0 indicates that command notification is not supported, while a value of 1 indicates that command notification is supported.

[0210] The D5-D4 data at address 0x06 is specification information indicating the communication method used to notify the camera 100 of the cause of the communication request after the accessory 200 has notified the camera 100 of the communication request signal / WAKE. If this information is 0, it indicates that the I2C communication method is the cause of the communication request; if it is 1, it indicates that the SPI communication method is the cause of the communication request; and if it is 2, it indicates that both the I2C communication method and the SPI communication method are the cause of the communication request.

[0211] The D3-D0 data at address 0x06 is specification information indicating whether accessory 200 has the functions corresponding to the FNC1 signal (function signal 1), FNC2 signal (function signal 2), FNC3 signal (function signal 3), and FNC4 signal (function signal 4). The D0 data corresponds to the FNC1 signal, the D1 data to the FNC2 signal, the D2 data to the FNC3 signal, and the D3 data to the FNC4 signal. A value of 0 indicates that the function is not present, and a value of 1 indicates that the function is present.

[0212] The D7 data at address 0x0A is specification information indicating whether or not accessory 200 requests camera 100 to start up when it notifies camera 100 of a communication request signal / WAKE. If this information is 0, it indicates that a start-up is requested, and if it is 1, it indicates that a start-up is not requested.

[0213] The D6-D0 data at address 0x0A contains information indicating the cause of the communication request signal / WAKE that accessory 200 notified camera 100 of.

[0214] Figure 8 shows an example of a cause of a communication request signal / WAKE (hereinafter also referred to as a communication request cause). Here, an example is shown where accessory 200 is a microphone device. For example, cause number 0x00 indicates that the menu call switch among the operation switches 212 has been operated (pressed). Cause number 0x01 indicates that accessory 200 has completed control of the audio signal output. Cause number 0x02 indicates that accessory 200 has completed the muting process of the audio signal (unmuted). In this embodiment, information on the communication request cause (number) as information on the cause of a communication request signal / WAKE is made available from accessory 200 to camera 100 as part of the accessory information.

[0215] In Figure 5, the D1 data at address 0x0C is specification information indicating the SPI communication protocol supported by accessory 200. A value of 0 indicates support for SPI protocol A, and a value of 1 indicates support for SPI protocol B.

[0216] The D0 data at address 0x0C is specification information indicating the control logic of the CS for SPI communication supported by accessory 200. If this information is 0, it indicates that CS is Lo active logic, and if it is 1, it indicates that CS is Hi active logic.

[0217] The D7-D0 data at address 0x0D is specification information indicating the time required as the communication byte interval when accessory 200 communicates using SPI protocol A and the D7 data at address 0x05 is 0, i.e., when accessory 200 is not in firmware update mode.

[0218] The D7-D0 data at address 0x0E is specification information indicating the time required as the communication byte interval when accessory 200 is communicating using SPI protocol A and the data at address 0x05D7 is 1, i.e., when accessory 200 is in firmware update mode.

[0219] Figures 9(a) and 9(b) show the time interval between communication bytes (communication intervals) corresponding to the data (0-7) at addresses 0x0D and 0x0E. Figure 9(a) shows the communication interval for the data at address 0x0D, and Figure 8(b) shows the communication interval for the data at address 0x0E.

[0220] In Figure 5, the data at address 0x0F is the checksum value data representing the sum of addresses from 0x00 to 0x0E.

[0221] Figure 10 shows the startup process performed by the camera control circuit A101 from the time the accessory 200 is attached to the camera 100 until the function of the accessory 200 is activated.

[0222] In S401, the camera control circuit A101 monitors the signal level of the accessory installation detection signal (first input signal) / ACC_DET and determines (detects) whether or not accessory 200 is installed. If the signal level of / ACC_DET is Hi, the camera control circuit A101 determines that accessory 200 is not installed and returns to S401 to determine installation again. If the signal level is Lo, it determines that accessory 200 is installed and proceeds to S402.

[0223] In S402, the camera control circuit A101 controls the power control signal CNT_VACC1 to a high level in order to turn on the output of the accessory power supply circuit A131. Then the process proceeds to S403. When the power control signal CNT_VACC1 reaches a high level, the accessory power supply circuit A131 outputs the accessory power (output signal) VAC.

[0224] In S403, the camera control circuit A101 monitors the signal level of the overcurrent detection signal DET_OVC to determine if an overcurrent is flowing. If the signal level of DET_OVC is low, the camera control circuit A101 determines that no overcurrent is flowing and proceeds to S404. If the signal level is high, it determines that an overcurrent is flowing and proceeds to S405 to perform error processing.

[0225] In S404, the camera control circuit A101 monitors the signal level of the communication request signal (second input signal) / WAKE, which is a notification signal from accessory 200, and determines whether or not the initialization of accessory 200 is complete. If the signal level of / WAKE is low (active), the camera control circuit A101 determines that initialization is complete and proceeds to S406. If the signal level is high, it determines that initialization is not complete and returns to S404 to determine if initialization is complete again.

[0226] In S406, the camera control circuit A101 performs I2C communication with accessory 200 as initial communication and reads 15 bytes of accessory information. Then it proceeds to S407.

[0227] In S407, the camera control circuit A101 determines, based on the accessory information read in S406, whether the installed accessory 200 is a device (compatible accessory) that corresponds to the camera 100. If the camera control circuit A101 determines that the installed accessory 200 is a compatible accessory, it proceeds to S408; if it determines that it is not a compatible accessory, it proceeds to S409 to perform error processing.

[0228] In S408, the camera control circuit A101 controls the power control signal CNT_VACC2 to a high level in order to turn on the output of the accessory power supply circuit B132. Then the process proceeds to S410. When the power control signal CNT_VACC2 reaches a high level, the accessory power supply circuit B132 outputs the accessory power supply VACC. In this embodiment, when both the power control signal CNT_VACC1 and the power control signal CNT_VACC2 reach a high level, the output from the accessory power supply circuit B132 is supplied to the accessory power supply VACC.

[0229] In S410, camera control circuit A101 notifies camera control circuit B102 of the accessory information read in S406. This completes the startup process on camera 100 associated with the attachment of accessory 200.

[0230] The flowchart in Figure 11 shows the activation process performed by the camera control circuit B102 from the time the accessory 200 is attached to the camera 100 until the functionality of the accessory 200 is activated.

[0231] In S501, the camera control circuit B102 determines whether or not accessory information has been notified from the camera control circuit A101. If accessory information has not been notified, the camera control circuit B102 returns to S501 to check for notification again, and if accessory information has been notified, proceeds to S502.

[0232] In S502, the camera control circuit B102 configures the function signals FNC1 to FNC4 based on the accessory information notified by the camera control circuit A101. For example, if accessory 200 is notified to be a microphone device, FNC1 is configured to function as the audio data clock signal BCLK, FNC2 as the audio data channel signal LRCLK, and FNC3 as the audio data signal SDATA. As another example, if accessory 200 is notified to be a strobe device, FNC4 is configured to function as the strobe flash synchronization signal XOUT. Function signals that do not require control for accessory 200 are also configured to ensure that the operation of camera 100 and accessory 200 is not affected.

[0233] In S503, the camera control circuit B102 sets the control logic for CS in SPI communication based on the accessory information notified from the camera control circuit A101.

[0234] In S504, the camera control circuit B102 determines whether a predetermined event has occurred for the accessory 200. If the event has not occurred, the camera control circuit B102 returns to S504 to determine if the event has occurred again; if the event has occurred, it proceeds to S505.

[0235] In S505, the camera control circuit B102 determines whether the event that occurred in S504 requires SPI communication with accessory 200. If the event requires SPI communication, the camera control circuit B102 proceeds to S506; otherwise, it proceeds to S507.

[0236] In S507, the camera control circuit B102 determines whether the event that occurred in S504 is an event that requires control of the accessory 200 using a function signal. If the event requires control using a function signal, the camera control circuit B102 proceeds to S508; otherwise, it proceeds to S509.

[0237] In S506, the camera control circuit B102 performs SPI communication with accessory 200. This SPI communication includes, for example, if accessory 200 is a microphone device, instructions to turn the microphone on, to turn the microphone off, to switch the microphone's pickup directionality, and to switch the microphone's equalizer function. If accessory 200 is a strobe device, this communication may include reading the strobe device's settings and notifying the strobe device of the settings. Once the SPI communication in S506 is complete, the camera control circuit B102 returns to S504 to determine if an event has occurred again.

[0238] In S508, the camera control circuit B102 controls the accessory 200 using function signals. For example, if the accessory 200 is a microphone device, it outputs the audio data clock signal BCLK from FNC1 and the audio data channel signal LRCLK from FNC2, and also receives the audio data signal SDATA from FNC3. This allows the camera 100 to acquire audio data from the microphone device. If the accessory 200 is a strobe device, it outputs the strobe flash synchronization signal XOUT from FNC4 at a predetermined timing. This allows the camera 100 to instruct the strobe device to flash. Once the control using these function signals is complete, the camera control circuit B102 returns to S504 to determine the occurrence of an event again.

[0239] Furthermore, in S509, the camera control circuit B102 performs predetermined in-camera control in response to the event that occurred in S504. For example, if accessory 200 is a microphone device, this control may include starting or stopping the recording of audio data to the recording memory 126, or performing equalizer processing on the audio data. If accessory 200 is a strobe device, this control may include photometering control to store and acquire the light emitted by the strobe device using the image sensor 122, or calculating the instruction value for the amount of light emitted by the strobe device. Once the in-camera control is complete, the camera control circuit B102 returns to S504 to determine if an event has occurred again.

[0240] The startup process by camera control circuit A101 and the activation process by camera control circuit B102 described above make it possible to control the accessory 200 to which the camera 100 is attached.

[0241] The flowchart in Figure 12 shows the processes that the accessory control circuit 201 executes from the time the accessory 200 is attached to the camera 100 until the various functions of the accessory 200 become available.

[0242] In S601, the accessory control circuit 201 waits for the accessory power supply VACC from the camera 100 to be turned on. If the accessory 200 does not have a battery 205, the accessory control circuit 201 can detect that the accessory power supply VACC has been turned on when power is supplied to the accessory control circuit 201 and the accessory control circuit 201 itself starts operating. If the accessory 200 has a battery 205, the accessory control circuit 201 may detect that the accessory power supply VACC has been turned on by monitoring the voltage value of the accessory power supply VACC.

[0243] In S602, the accessory control circuit 201 performs predetermined initial settings. For example, it sets the microcontroller's operating frequency, the microcontroller's input / output control ports, the microcontroller's timer function, and the microcontroller's interrupt function.

[0244] Once the initial setup in S602 is complete, in S603, the accessory control circuit 201 controls the communication request signal / WAKE to a low level. This notifies the camera 100 that the initial setup is complete.

[0245] In S604, the accessory control circuit 201 responds to I2C communication from the camera 100 by sending 15 bytes of accessory information to the camera 100 as initial communication. The accessory information includes various pieces of information as shown in Figure 5.

[0246] Once the initial communication in S604 is complete, in S605 the accessory control circuit 201 controls the communication request signal / WAKE to a high level.

[0247] In S606, the accessory control circuit 201 determines whether a predetermined event has occurred. If the event has not occurred, the accessory control circuit 201 returns to S606 to determine if the event has occurred again; if the event has occurred, it proceeds to S607.

[0248] In S607, the accessory control circuit 201 determines whether the event that occurred in S606 requires SPI communication with the camera 100. If the event requires SPI communication, the accessory control circuit 201 proceeds to S608; otherwise, it proceeds to S609.

[0249] In S609, the accessory control circuit 201 determines whether the event that occurred in S606 requires I2C communication with the camera 100. If the event requires I2C communication, the accessory control circuit 201 proceeds to S610; otherwise, it proceeds to S611.

[0250] In S611, the accessory control circuit 201 determines whether the event that occurred in S606 is an event that requires control using a function signal. If the event requires control using a function signal, the accessory control circuit 201 proceeds to S612; otherwise, it proceeds to S613.

[0251] In S613, the accessory control circuit 201 determines whether the event that occurred in S606 is an event that requires notification to the camera 100 via a communication request signal / WAKE. If the event requires notification to the camera 100 via a communication request signal / WAKE, the accessory control circuit 201 proceeds to S614; otherwise, it proceeds to S615.

[0252] In S608, the accessory control circuit 201 performs SPI communication with the camera 100. If the communication request signal / WAKE is at a low level when the SPI communication is performed, the communication request signal / WAKE is controlled to a high level after the SPI communication is completed. The SPI communication performed here may include, for example, if the accessory 200 is a microphone device, communications to turn on the microphone operation from the camera 100, communications to turn off the microphone operation, and communications to switch the microphone's pickup directionality. There may also be communications to switch the microphone's equalizer function. If the accessory 200 is a strobe device, there may be communications to read the strobe device's setting information and communications to notify the strobe device of the setting information. Once the predetermined SPI communication in S608 is completed, the accessory control circuit 201 returns to S606 and determines the occurrence of an event again.

[0253] In S610, the accessory control circuit 201 performs I2C communication with the camera 100. If the communication request signal / WAKE is at a low level when the I2C communication is performed, the communication request signal / WAKE is controlled to a high level after the I2C communication. The I2C communication performed here may include, for example, communication to read the communication request factor for the communication request signal / WAKE notified from the accessory control circuit 201 to the camera 100. Once the I2C communication in S610 is complete, the accessory control circuit 201 returns to S606 and determines the occurrence of an event again.

[0254] In S612, the accessory control circuit 201 controls the camera 100 using function signals. For example, if accessory 200 is a microphone device, it controls the reception of the audio data clock signal BCLK of FNC1 and the audio data channel signal LRCLK of FNC2 output from camera 100. Furthermore, it controls the output of the audio data signal SDATA of FNC3, which is synchronized with these signals. If accessory 200 is a strobe device, it controls the reception of the strobe flash synchronization signal XOUT of FNC4 and controls the strobe flash accordingly. Once the control using function signals in S612 is complete, the accessory control circuit 201 returns to S606 to determine the occurrence of an event again.

[0255] In S614, the accessory control circuit 201 stores the communication request factor number for the camera 100 corresponding to the event that occurred in S606 in the accessory 200's volatile memory (not shown), and controls the communication request signal / WAKE to a Lo level. The communication request factor number is a unique number assigned to each factor, as shown in Figure 8. Once the control of the communication request signal / WAKE to a Lo level in S614 is complete, the accessory control circuit 201 returns to S606 and determines the occurrence of another event.

[0256] In S615, the accessory control circuit 201 performs in-accessory control in response to the event that occurred in S606. This in-accessory control may include detecting the remaining battery level if the accessory 200 is equipped with a battery 205, or detecting the operation of the operation switch 212. Once the in-accessory control in S615 is complete, the accessory control circuit 201 returns to S606 to determine if an event has occurred again.

[0257] Through the processing performed by the accessory control circuit 201 described above, the accessory 200 can perform various functional operations after being attached to the camera 100.

[0258] Figure 13 shows the processes performed by camera control circuit A101 and camera control circuit B102 when the accessory 200 is attached to the camera 100 when the camera 100 is powered on, in the processing sequence shown in Figure 6. The same processes as in Figure 6 will not be explained.

[0259] Camera control circuit A101, in parallel with accessory detection processing using the accessory detection signal / ACC_DET, supplies the camera microcontroller power supply VMCU2_C to camera control circuit B, thereby turning on the power to camera control circuit B102. Upon power-on, camera control circuit B102 performs its own initialization process, and once the initialization process is complete, it notifies camera control circuit A101 that it is ready.

[0260] Upon receiving notification that preparation is complete, the camera control circuit 101A notifies the camera control circuit B102 of the accessory information it had obtained from the accessory 200.

[0261] Through the above process, the camera control circuit A101 can execute the process of detecting the attachment of accessory 200 to camera 100 and the process of activating camera control circuit B102 in parallel. Therefore, the startup time of accessory 200 (i.e., the imaging system) can be shortened. In other words, the responsiveness during startup can be improved. [Examples]

[0262] Next, Embodiment 2 of the present invention will be described. Figures 14(a) and (b) show the processes performed by camera control circuit A101 and camera control circuit B102 when the accessory 200 is attached to the camera 100 while the camera 100 is in low power consumption mode (sleep mode) in the processing sequence shown in Figure 6. The same processes as in Figure 6 will not be explained.

[0263] In Figure 14(a), when the camera control circuit A101 detects the attachment of accessory 200 in low power consumption mode, it does not supply power to the camera control circuit B102 shown in Figure 13, but only outputs power for the accessory and acquires accessory information.

[0264] Furthermore, in Figure 14(b), power is supplied to the camera control circuit B102 when switching from low-power mode to normal operation mode due to input detection. Once the initialization process is complete, the camera control circuit B102 notifies the camera control circuit A101 that it is ready.

[0265] Upon receiving notification that preparation is complete, camera control circuit A101 notifies camera control circuit B102 of the accessory information acquired in Figure 14(a).

[0266] Upon receiving accessory information, the camera control circuit B102 switches control over the accessory based on the accessory information and performs accessory control communication and function signal control for the accessory 200.

[0267] As a result of the above processing, the camera 100 can skip the accessory detection process when starting up from low power consumption mode, thereby shortening the startup time of the accessory 200 (i.e., the imaging system). In other words, the responsiveness during startup can be improved. [Examples]

[0268] Next, Embodiment 3 of the present invention will be described. The camera 100 has a shutter button (not shown), and a first shutter switch (hereinafter referred to as SW1) and a second shutter switch (hereinafter referred to as SW2) that are turned ON by the operation of the shutter button. SW1 is turned ON by a half-press operation of the shutter button and instructs the start of imaging preparation operations such as automatic exposure control and focus control. SW2 is turned ON by a full-press operation of the shutter button and instructs still image capture.

[0269] Normally, after waiting for the imaging preparation operation to complete by turning on the SWI, SW2 is turned on. However, there may be a case where the shutter button is fully pressed at once so that SW2 is turned on almost simultaneously following the turning on of SW1. In this embodiment, when the shutter button is fully pressed at once in this way and SW1 and SW2 are turned on almost simultaneously, it is referred to as SW1 / SW2 simultaneous ON.

[0270] The flowchart in FIG. 19 shows the processing executed by the camera control circuit B102 when SW1 / SW2 is simultaneously ON.

[0271] First, in S701, the camera control circuit B102 receives accessory information from the camera control circuit A101 through the communication exchange shown in FIG. 13 or FIG. 14.

[0272] Next, in S702, the camera control circuit B102 determines whether SW2 is ON (that is, SW1 / SW2 is simultaneously ON). If it is ON, the process proceeds to step S703.

[0273] In S703, the camera control circuit B102 refers to the accessory information acquired in S701 and determines whether the accessory 200 is a strobe device. If the accessory 200 is a strobe device, the process proceeds to S704. If it is not a strobe device, the process proceeds to S707. <00009X1>

[0274] In S704, the camera control circuit B102 performs SPI communication necessary for strobe imaging with the accessory 200. Through this SPI communication, charge completion information indicating whether the charging of the accessory 200 is complete is also obtained.

[0275] Next, in S705, the camera control circuit B102 refers to the charge completion information obtained in S704 and determines whether the charging of the accessory 200 is complete. If the charging is complete, the process proceeds to S706. If the charging is not complete, the process proceeds to S707.

[0276] In S706, the camera control circuit B102 permits flash imaging and proceeds to the next step, S708. If automatic exposure control or focus control is not yet complete at this point, flash imaging is not permitted, and the system waits for both controls to be completed.

[0277] In the S708, the camera control circuit B102 controls the flash output of accessory 200 and determines the amount of flash emitted during image capture.

[0278] Subsequently, the camera control circuit B102 proceeds to S709, where it fires the strobe light with the amount of flash determined in S708 and performs the main image capture. Then, the main process is completed.

[0279] Meanwhile, in S707, the camera control circuit B102 permits non-strobe (non-flash) imaging and proceeds to S710. If automatic exposure control and focus control are not completed at this point, non-strobe imaging is not permitted, and the system waits for both controls to be completed.

[0280] Subsequently, the camera control circuit B102 proceeds to S710, where it performs the main image capture without causing the accessory 200 to flash. Then, the process ends.

[0281] The flowchart in Figure 20, as a comparative example, shows a process that differs from the process shown in Figure 19, which is executed by the camera control circuit B102 when SW1 / SW2 are simultaneously turned ON.

[0282] In step S801, the camera control circuit B102 determines whether SW2 is ON (SW1 / SW2 are ON simultaneously) without performing the accessory information reception processing corresponding to S701 in Figure 19. If it is ON, the process proceeds to step S802, and SPI communication is performed with accessory 200, similar to S704 in Figure 19.

[0283] Next, in S803, the camera control circuit B102 determines from the information obtained from the SPI communication in S802 whether or not accessory 200 is a fully charged strobe device. If it is a fully charged strobe device, the process proceeds to S804; otherwise, it proceeds to S805. S804 to S808 are the same as S706 to S710 in Figure 19, respectively.

[0284] In the process shown in Figure 20, the camera control circuit B102 does not acquire accessory information from accessory 200 in advance. Therefore, when SW2 is turned ON (S801), it always performs SPI communication with accessory 200 (S802).

[0285] However, if accessory 200 is not a strobe device, SPI communication is not necessary for controlling imaging. Nevertheless, performing unnecessary SPI communication increases the time lag before imaging can be permitted. In contrast, as shown in Figure 19, by acquiring accessory information in advance with S701, imaging can be permitted without performing SPI communication (S704) when an accessory other than a strobe device is attached, thereby reducing the time lag. [Examples]

[0286] Next, Embodiment 4 of the present invention will be described. The camera 100 performs live view display using the display circuit 127. Normally, the brightness of the live view image is adjusted to be the same as the brightness of the captured image. However, when a strobe device is attached as an accessory 200, the brightness of the captured image obtained by strobe imaging is unknown until the image is captured, so the brightness of the live view image is adjusted as follows.

[0287] For example, suppose a subject for which a properly exposed image can be obtained with F4, shutter speed 1 / 60s, and ISO 400, and the user manually sets Camera 100 to F4, 1 / 60s, and ISO 100. In this case, the exposure of the captured image will be 2 stops underexposed, so the brightness of the live view image may also be set to 2 stops underexposed. However, if the attached accessory 200 is a fully charged flash unit, the brightness setting of the live view image should be changed. This is because even if the exposure is underexposed, the flash light may correct it to the proper exposure.

[0288] The flowchart in Figure 21 shows the live view display process executed by the camera control circuit B102 when the camera 100 is started up.

[0289] First, in S901, the camera control circuit B102 receives accessory information from the camera control circuit A101 through the communication exchange shown in Figure 13 or Figure 14.

[0290] Next, in step S902, the camera control circuit B102 determines whether or not there has been an instruction to display live view (LV). If there has been an instruction, it proceeds to step S903; otherwise, it repeats the determination in this step.

[0291] In S903, the camera control circuit B102 refers to the accessory information obtained in S901 and determines whether accessory 200 is a strobe device or not. If it is a strobe device, the process proceeds to S904; otherwise, it proceeds to S907.

[0292] In the S904, the camera control circuit B102 performs SPI communication with the accessory 200 to obtain charging status information.

[0293] Next, in S905, the camera control circuit B102 refers to the charging information obtained in S904 to determine whether or not charging of accessory 200 is complete. If charging is complete, proceed to S906; otherwise, proceed to S907.

[0294] In S906, the camera control circuit B102 sets the brightness of the live view image to the brightness corresponding to the original proper exposure (for example, F4, 1 / 60s, ISO400) and causes the display circuit 127 to perform live view display. Then, it proceeds to S908.

[0295] On the other hand, in S907, the camera control circuit B102 sets the brightness of the live view image to the brightness corresponding to the imaging exposure (for example, F4, 1 / 60s, ISO100) and causes the display circuit 127 to perform live view display. Then, it proceeds to S908.

[0296] In S908, the camera control circuit B102 determines whether the photometry timer is counting. If the photometry timer is counting, it proceeds to S909; if not, it repeats the determination in this step. The photometry timer starts counting at the timing when SW1 is turned ON and counts for the specified time.

[0297] The processing related to the live view display during the counting of the photometry timer (S909 to S913) is the same as the processing related to the live view display before the counting of the photometry timer starts (S903 to S907). Therefore, as long as the state of the accessory 200 such as the charge state does not change, the brightness of the live view image is the same before and after the start of the counting of the photometry timer.

[0298] The flowchart of FIG. 22 shows, as a comparative example, a live view display process different from the process shown in FIG. 21 that the camera control circuit B102 executes when the camera 100 is started.

[0299] In S1001, the camera control circuit B102 determines whether there is an instruction for LV display without performing the reception process of the accessory information corresponding to S901 in FIG. 20. If there is an instruction, it proceeds to S1002; if not, it repeats the determination in this step.

[0300] In S1002, the camera control circuit B102 sets the brightness of the live view image to match the exposure of the image being captured, and causes the display circuit 127 to display the live view.

[0301] Next, in S1003, the camera control circuit B102 determines whether the metering timer is counting or not. If the metering timer is counting, the process proceeds to S1004; otherwise, the process in this step is repeated.

[0302] In S1004, the camera control circuit B102 uses SPI communication to obtain information from accessory 200, which is a strobe device. By performing SPI communication only while the metering timer is counting, power consumption can be reduced.

[0303] Next, in S1005, the camera control circuit B102 determines, based on the information obtained from the SPI communication in S1004, whether or not the accessory 200 is a fully charged strobe device. If it is a fully charged strobe device, the process proceeds to S1006; otherwise, it proceeds to S1007.

[0304] In S1006, the camera control circuit B102 sets the brightness of the live view image to a level equivalent to proper exposure and causes the display circuit 127 to display the live view. Then this process ends.

[0305] Meanwhile, in S1007, the camera control circuit B102 sets the brightness of the live view image to match the exposure of the image capture, and causes the display circuit 127 to display the live view. Then this process ends.

[0306] In the process shown in Figure 22, the camera control circuit B102 cannot obtain accessory information in advance. Therefore, in S1002, the camera control circuit B102 first displays the live view at a brightness equivalent to the image exposure, and then, if the strobe device is fully charged, switches the brightness of the live view display to a brightness equivalent to the correct exposure (S1006). As a result, changes in brightness occur in the live view display.

[0307] In contrast, in the process shown in Figure 21, the camera control circuit B102 can acquire accessory information in advance at S901, and therefore can control the live view display to the appropriate brightness for the accessory 200 from the time of the initial live view display (S906, S907). As a result, there is no change in the brightness of the live view display.

[0308] In the embodiments described above, the case where the first communication method is the I2C communication method and the second communication method is the SPI communication method was explained, but the first and second communication methods may be communication methods other than I2C and SPI communication methods.

[0309] Furthermore, although imaging devices were described as electronic devices in the above embodiments, the term "electronic device" in this invention also includes various other electronic devices besides imaging devices.

[0310] Furthermore, although the above embodiment describes a case where the accessory 200 is directly attached to the camera 100, other attachment configurations are also possible. For example, the camera 100 and the main accessory may communicate via an intermediate accessory such as an adapter device to which the main accessory (corresponding to the accessory 200) and the camera 100 are attached. In this case, the intermediate accessory may perform communication control similar to at least a part of the communication control performed by the accessory 200 and the camera 100 as described in the above embodiment. Alternatively, the intermediate accessory may function as an information transmission path, outputting information corresponding to information input from the camera 100 to the main accessory, and outputting information corresponding to information input from the main accessory to the camera 100. Thus, the accessories in the embodiment of the present invention include a variety of accessories such as microphone devices, lighting devices, and adapter devices. Furthermore, the adapter device may also be an electronic device.

[0311] (Other examples) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0312] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of symbols]

[0313] 100 Cameras 101 Camera control circuit A 102 Camera control circuit B 200 Accessories 201 Accessory Control Circuit

Claims

1. An electronic device on which accessories can be attached and detached, A first processing means capable of communicating with the accessory using a first communication method, It has a second processing means that enables communication with the accessory using a second communication method different from the first communication method, The electronic device has a first power state in which it is capable of communicating with the accessory, and a second power state in which it consumes less power than the first power state. The first processing means is comprised of a processor that operates at lower power than the processor comprising the second processing means. The first processing means communicates with the accessory using the first communication method in the first power state and the second power state. The second processing means is characterized by communicating with the accessory using the second communication method in the first power state, and not sending or receiving information with the accessory using the second communication method in the second power state. An electronic device characterized in that the contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different.

2. The electronic device according to claim 1, characterized in that the first processing means and the second processing means are provided within a single processor.

3. The electronic device according to claim 1 or 2, characterized in that the first communication method has a lower communication speed than the second communication method.

4. The electronic device according to any one of claims 1 to 3, characterized in that the first processing means receives accessory information for identifying the accessory from the accessory in the first communication method in response to detecting the attachment of the accessory to the electronic device, before the second processing means becomes able to communicate with the accessory.

5. When the aforementioned electronic device is started up, The first processing means is activated before the second processing means, and detects the attachment of the accessory and activates the second processing means in parallel. The electronic device according to any one of claims 1 to 4, characterized in that it notifies the activated second processing means of accessory information for identifying the accessory from the accessory.

6. The electronic device according to claim 5, characterized in that the accessory information includes information indicating the type of accessory and information indicating the specifications of the accessory.

7. The electronic device according to any one of claims 1 to 6, characterized in that the first processing means outputs an output signal to the accessory by detecting a first input signal activated by the accessory in response to the accessory being attached to the electronic device, and detects that communication with the accessory in the first communication method is to be performed in response to detecting a second input signal activated by the accessory that has received the output signal.

8. The electronic device according to any one of claims 1 to 7, characterized in that the contact that receives accessory information for identifying the accessory from the accessory in the first communication method is a different contact from the contact that performs communication for controlling the accessory in the second communication method.

9. The electronic device according to any one of claims 1 to 8, characterized in that the first communication method is an I2C communication method and the second communication method is an SPI communication method.

10. The electronic device has a plurality of contacts arranged in a row so as to be electrically connected to a plurality of contacts arranged in a row in the accessory, The multiple contacts of the electronic device are It includes a contact for data signals in the I2C communication system and a contact for clock signals in the I2C communication system located on one side of the data signal contact, and further, The electronic device according to claim 7, characterized in that it includes a second input signal contact, an input selection signal contact for an SPI communication system, a receiving contact for an SPI communication system, a transmitting contact for an SPI communication system, a clock signal contact for an SPI communication system, a first input signal contact, and an output signal contact, all of which are located on the other side of the data signal contact.

11. An electronic device according to any one of claims 1 to 10, A system characterized by having an accessory that is detachably and communicatively attached to the electronic device.

12. An accessory that is detachably attached to an electronic device, The device has accessory processing means capable of communicating with the electronic device using a first communication method and a second communication method different from the first communication method. The accessory processing means is The electronic device communicates with the accessory using the first communication method in a first power state in which the electronic device is capable of communicating with the accessory, and in a second power state in which the power consumption is lower than that of the first power state. The electronic device communicates with the electronic device using the second communication method in the first power state, and the electronic device does not send or receive information with the electronic device using the second communication method in the second power state. The contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different. The accessory is characterized in that the first communication method has a lower communication speed than the second communication method.

13. The accessory according to claim 12, wherein the accessory processing means transmits accessory information to the electronic device for identifying the accessory in the first communication method, and the accessory information includes information indicating the type of accessory and information regarding the communication and operation specifications of the accessory.

14. The accessory according to claim 12 or 13, wherein the accessory processing means transmits accessory information for identifying the accessory from the accessory to the electronic device using the first communication method before communication using the second communication method becomes possible.

15. The accessory according to any one of claims 12 to 14, characterized in that the accessory processing means activates a first input signal that is input to the electronic device in response to the accessory being attached to the electronic device, activates a second input signal that is input to the electronic device upon receiving an output signal output from the electronic device that has detected the first input signal, and communicates with the electronic device that has detected the second input signal using the first communication method.

16. The accessory according to any one of claims 12 to 15, characterized in that the contact for transmitting accessory information for identifying the accessory from the accessory in the first communication method is a different contact from the contact for performing communication for controlling the accessory in the second communication method.

17. The accessory according to any one of claims 12 to 16, characterized in that the first communication method is an I2C communication method and the second communication method is an SPI communication method.

18. The accessory has a plurality of contacts arranged in a row so as to be electrically connected to a plurality of contacts arranged in a row in the electronic device, The multiple contacts of the accessory are It includes a contact for data signals in the I2C communication system and a contact for clock signals in the I2C communication system located on one side of the data signal contact, and further, The accessory according to claim 15, characterized in that it includes a second input signal contact, an input selection signal contact for an SPI communication system, a transmit contact for an SPI communication system, a receive contact for an SPI communication system, a clock signal contact for an SPI communication system, a first input signal contact, and an output signal contact, all of which are located on the other side of the data signal contact.

19. An accessory according to any one of claims 12 to 18, A system characterized by having an electronic device to which the accessory is detachably and communicatively attached.

20. A control method for electronic equipment having a first processing means and a second processing means, wherein an accessory is detachably attached, The electronic device has a first power state in which it is capable of communicating with the accessory, and a second power state in which it consumes less power than the first power state. The first processing means communicates with the accessory using a first communication method in the first power state and the second power state. The second processing means is configured to communicate with the accessory using a second communication method different from the first communication method in the first power state, and not to transmit or receive information with the accessory using the second communication method in the second power state. The contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different. A control method characterized in that the first processing means is composed of a processor that operates at lower power than the processor constituting the second processing means.

21. A method for controlling an accessory that is detachably attached to an electronic device, The accessory is configured to communicate with the electronic device using a first communication method in a first power state in which the electronic device is capable of communicating with the accessory, and in a second power state in which the power consumption is lower than that of the first power state. The accessory is configured such that the electronic device communicates with the electronic device using a second communication method different from the first communication method in the first power state, and the electronic device does not transmit or receive information with the electronic device using the second communication method in the second power state. The contacts that communicate using the first communication method and the contacts that communicate using the second communication method are different. A control method characterized in that the first communication method has a lower communication speed than the second communication method.

22. A program characterized by causing a computer of an electronic device to which an accessory is detachably attached to perform processing according to the control method described in claim 20.

23. A program characterized by causing a computer in an accessory that is detachably attached to an electronic device to perform processing according to the control method described in claim 21.

Images