JP2018164228A - Accessory device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device and an accessory device capable of communicating by a plurality of communication methods and capable of appropriately communicating when switching from a second power state to a first power state.
An interchangeable lens 100 as an accessory device switches between a first power state communicable with a camera body 200 as an imaging device and a second power state in which power consumption is smaller than the first power state. A power control unit 113 is included. In addition, the interchangeable lens 100 includes a setting unit 114 that sets a communication method of communication performed with the imaging device when the second power state is switched to the first power state.
[Selection] Figure 1

Description

  The present invention relates to an accessory device and an imaging device that can communicate with each other.

  As a lens interchangeable camera system, a system is known in which a camera body as an imaging device issues a control command to a lens device as an accessory device. In such an interchangeable lens camera system, in order to transmit commands from the camera body to the interchangeable lens, and to transmit lens information from the interchangeable lens to the camera body, the camera body and the lens device communicate via a communication line. It is known to do.

  Patent Document 1 describes a camera body and an interchangeable lens that correspond to a clock synchronous serial communication method and an asynchronous serial communication method and can perform communication while switching the communication method.

  Further, Patent Document 2 discloses a first power state (active state) in which communication is constantly performed with the camera body, and a second that consumes less power than the first power state without communication with the camera body. An accessory device is described that can be switched between the power state (sleep state).

Japanese Patent No. 5517486 JP 2014-235449 A

  In an interchangeable lens that communicates with the camera body while switching between the two communication methods, when the communication method does not match the camera body when switching from the second power state to the first power state, it communicates appropriately with the camera body There is a problem that it becomes impossible to perform.

  An object of the present invention is to provide an accessory device and an imaging device that can communicate by a plurality of communication methods and can appropriately communicate when switching from the second power supply state to the first power supply state. is there.

  An accessory device according to the present invention is an accessory device that is detachably attached to an imaging device and is capable of communicating with the imaging device in a plurality of communication modes, the first power state being capable of communicating with the imaging device, and the first A power control unit that switches between a second power state that consumes less power than the first power state in response to receiving a signal transmitted from the imaging device, and the first power state from the second power state. A setting unit configured to set a communication method of communication performed with the imaging device when the power state is switched.

  According to the present invention, it is possible to realize an accessory device and an imaging device that can communicate by a plurality of communication methods and can perform appropriate communication when switching from the second power supply state to the first power supply state. it can.

It is a block diagram which shows the structure of an imaging device and an accessory apparatus. It is the schematic which shows the communication circuit between an imaging device and an accessory apparatus. It is the schematic which shows the communication waveform at the time of communicating by a clock synchronous serial communication system. It is the schematic which shows the communication waveform at the time of communicating by an asynchronous serial communication system. It is a flowchart explaining the flow at the time of determining the communication system of the communication performed between an imaging device and an accessory apparatus. It is the schematic which shows the communication waveform at the time of switching a communication system. It is a flowchart explaining the flow at the time of switching the electric power state of the accessory apparatus of Example 1. FIG. It is a flowchart explaining the flow at the time of switching the electric power state of the accessory apparatus of Example 2. FIG.

  Embodiments of an accessory device and an imaging device according to the present invention will be described below in detail with reference to the accompanying drawings.

[Example 1]
The interchangeable lens as the accessory device according to the first exemplary embodiment is configured to be able to switch between a first power state and a second power state, which will be described later, in response to receiving a signal from the camera body as the imaging device. In addition, the camera body and the interchangeable lens according to the present embodiment can transmit control commands and internal information via a communication unit included in each. Each communication unit is configured to be able to communicate with a first communication method and a second communication method, which will be described later, and in synchronization with each other according to the type of communication data and the communication purpose, the same communication method (synchronization method). By switching, it is possible to select an optimal communication method for various situations.

  In the interchangeable lens and the camera body of the present embodiment, a communication method of communication performed when the power state of the interchangeable lens is switched is set in advance by a lens side setting unit and a camera side setting unit described later. Thereby, when the power state is switched, communication between the interchangeable lens and the camera body can be appropriately performed.

  First, specific configurations of the interchangeable lens 100 and the camera body 200 of the present embodiment will be described. FIG. 1 illustrates a configuration of an imaging system (hereinafter referred to as a camera system) including the camera body 200 and the interchangeable lens 100 according to the present embodiment. FIG. 1 shows a state where the interchangeable lens 100 is detachably attached to the camera body 200.

  The interchangeable lens 100 and the camera body 200 are mechanically and electrically connected via a mount 300 that is a coupling mechanism. The interchangeable lens 100 receives power from the camera body 200 via a power terminal (not shown) provided on the mount 300 and controls various actuators and a lens microcomputer (hereinafter referred to as a lens microcomputer) 111 which will be described later. Further, the interchangeable lens 100 and the camera body 200 communicate with each other via a communication terminal provided on the mount 300.

  The interchangeable lens 100 has an imaging optical system. The imaging optical system includes, in order from the subject OBJ side, a field lens 101, a zoom lens 102 that performs zooming, an aperture unit 114 that adjusts the amount of light, an image blur correction lens 103, and a focus lens 104 that performs focus adjustment. including.

  The variable power lens 102 and the focus lens 104 are held by lens holding frames 105 and 106, respectively. The lens holding frames 105 and 106 are guided by a guide shaft (not shown) so as to be movable in a direction along the optical axis indicated by a broken line in the drawing, and are driven in a direction along the optical axis by stepping motors 107 and 108, respectively. The The stepping motors 107 and 108 move the variable power lens 102 and the focus lens 104 in synchronization with the drive pulse, respectively.

  The image blur correction lens 103 moves in a direction orthogonal to the optical axis of the imaging optical system, thereby reducing image blur due to camera shake or the like.

  The lens microcomputer 111 is an accessory control unit that controls the operation of each unit in the interchangeable lens 100. The lens microcomputer 111 includes a lens communication unit 112 including a lens data transmission / reception unit 112b that transmits and receives data via a communication interface (I / F) circuit 112a (shown in FIG. 2). The lens microcomputer 111 performs lens control corresponding to the control command received from the camera body 200 or transmits lens data corresponding to the transmission request to the camera body 200 via the lens communication unit 112. The lens data includes optical information of the interchangeable lens 100, characteristic information (lens ID) unique to the interchangeable lens 100, and the like.

  In addition, the lens microcomputer 111 outputs drive signals to the zoom drive circuit 119 and the focus drive circuit 120 in response to commands relating to scaling and focusing among the control commands to drive the stepping motors 107 and 108. Thus, zoom processing for controlling the zooming operation by the zoom lens 102 and autofocus processing for controlling the focus adjustment operation by the focus lens 104 are performed.

  The diaphragm unit 114 includes diaphragm blades 114a and 114b. The states of the diaphragm blades 114 a and 114 b are detected by the hall element 115 and input to the lens microcomputer 111 via the amplifier circuit 122 and the A / D conversion circuit 123. The lens microcomputer 111 outputs a drive signal to the aperture drive circuit 121 based on the input signal from the A / D conversion circuit 123 to drive the aperture actuator 113. Thereby, the light quantity adjustment operation by the diaphragm unit 114 is controlled.

  Further, the lens microcomputer 111 drives the image stabilization actuator 126 via the image stabilization drive circuit 125 in accordance with a shake detected by a shake sensor (not shown) such as a vibration gyro provided in the interchangeable lens 100. As a result, an image stabilization process for controlling the shift operation of the image blur correction lens 103 is performed.

  The lens microcomputer 111 also includes a power control unit 113 that controls the power state of the interchangeable lens. The power control unit 113 switches between the first power state and the second power state that consumes less power than the first power state.

  When the interchangeable lens 100 is in the first power state, the lens microcomputer 111 is in an active state and constantly communicates with the camera body 200. When the interchangeable lens 100 is in the second power state, the lens microcomputer 111 is in the sleep state. In this case, the lens microcomputer 111 waits until a command for switching to the first power state is transmitted from the camera body 200.

  The power control by the power control unit 113 is performed in response to the lens microcomputer 111 receiving a predetermined control command from the camera body 200. As for switching from the first power state to the second power state, when the lens microcomputer 111 has not received a predetermined control command from the camera body 200, the power control unit 113 performs switching spontaneously. May be.

  In addition, the lens microcomputer 111 includes a lens side setting unit 114 that presets a communication method of communication performed with the camera body 200 when the power state of the interchangeable lens 100 is switched from the second power state to the first power state. Have.

  The camera body 200 includes an imaging device 201 such as a CCD sensor or a CMOS sensor, an A / D conversion circuit 202, a signal processing circuit 203, a recording unit 204, a camera microcomputer (hereinafter referred to as camera microcomputer) 205, a display. Part 206.

  The image sensor 201 photoelectrically converts the subject image formed by the imaging optical system in the interchangeable lens 100 and outputs an electrical signal (analog signal). The A / D conversion circuit 202 converts an analog signal from the image sensor 201 into a digital signal. The signal processing circuit 203 performs various image processing on the digital signal from the A / D conversion circuit 202 to generate a video signal.

  The signal processing circuit 203 also generates focus information indicating the contrast state of the subject image, that is, the focus state of the imaging optical system, and luminance information indicating the exposure state from the video signal. The signal processing circuit 203 outputs the video signal to the display unit 206, and the display unit 206 displays the video signal as a live view image used for checking the angle of view, the focus state, and the like.

  A camera microcomputer 205 as a camera control unit controls the camera body 200 in response to inputs from camera operation members such as an imaging instruction switch and various setting switches (not shown). The camera microcomputer 205 includes a camera communication unit 208 including a camera data transmission / reception unit 208b that transmits / receives data via a communication interface (I / F) circuit 208a (shown in FIG. 2). It transmits to the microcomputer 111.

  In addition, the camera microcomputer 205 includes a camera-side setting unit 206 that presets a communication method of communication performed with the lens microcomputer 111 when the power state of the interchangeable lens 100 is switched from the first power state to the second power state. .

  Next, a communication circuit configured between the camera body 200 and the interchangeable lens 100 and communication control performed between them will be described with reference to FIG. The camera microcomputer 205 has a function of managing a communication method of communication performed with the lens microcomputer 111 and a function of notifying the lens microcomputer 111 of a transmission request or the like. The lens microcomputer 111 has a function of generating lens data and a function of transmitting lens data.

  The camera microcomputer 205 and the lens microcomputer 111 communicate with communication terminals provided on the mount 300 via communication interface circuits 208a and 112a provided respectively.

  In this embodiment, the camera microcomputer 205 and the lens microcomputer 111 use three channels (communication lines) to communicate with a 3-wire clock synchronous serial communication system and a 3-wire asynchronous serial communication system. I do. Hereinafter, the three-wire clock synchronous serial communication method is referred to as communication method A, and the three-wire asynchronous serial communication method is referred to as communication method B.

  One of the three channels is a notification channel that is a clock channel in the communication method A and a transmission request channel in the communication method B. One of the other two channels is a first data communication channel used for lens data transmission from the lens microcomputer 111 to the camera microcomputer 205. The other channel is a second data communication channel used for transmitting camera data from the camera microcomputer 205 to the lens microcomputer 111.

  Lens data transmitted as a signal from the lens microcomputer 111 to the camera microcomputer 205 through the first data communication channel is referred to as a lens data signal DLC. The camera data transmitted as a signal from the camera microcomputer 205 to the lens microcomputer 111 through the second data communication channel is referred to as a camera data signal DCL.

  First, communication in communication method A will be described. In the communication method A, the clock signal LCLK is output from the camera microcomputer 205 as the communication master to the lens microcomputer 111 as the communication slave via the clock channel. The camera data signal DCL includes a control command from the camera microcomputer 205 to the lens microcomputer 111, a transmission request command, and the like. On the other hand, the lens data signal DLC includes various data transmitted from the lens microcomputer 111 to the camera microcomputer 205 in synchronization with the clock signal LCLK. The camera microcomputer 205 and the lens microcomputer 111 can communicate with each other by a full-duplex communication system (full-duplex system) that performs transmission and reception mutually and simultaneously in synchronization with a common clock signal LCLK.

  3A to 3C show waveforms of signals exchanged between the camera microcomputer 205 and the lens microcomputer 111 in the communication method A. The protocol for this exchange is called a communication protocol.

  FIG. 3A shows a signal waveform of one frame which is the minimum communication unit. First, the camera microcomputer 205 outputs a clock signal LCLK including a set of eight clock pulses, and transmits a camera data signal DCL to the lens microcomputer 111 in synchronization with the clock signal LCLK. At the same time, the camera microcomputer 205 receives the lens data signal DLC output from the lens microcomputer 111 in synchronization with the clock signal LCLK.

  In this manner, 1-byte (8-bit) data is transmitted / received between the lens microcomputer 111 and the camera microcomputer 205 in synchronization with a set of clock signals LCLK. This 1-byte data transmission / reception period is called a data frame. After the transmission / reception of the 1-byte data, the lens microcomputer 111 transmits a signal (hereinafter referred to as a BUSY signal) for notifying the camera microcomputer 205 of a communication standby request BUSY, thereby inserting a communication standby period. This communication standby period is referred to as a BUSY frame, and the camera microcomputer 205 is in a communication standby state while receiving the BUSY frame. And the communication unit which makes a data frame and a BUSY frame 1 set becomes one frame. Depending on the communication status, the BUSY frame may not be added. In this case, one frame is composed of only data frames.

  FIG. 3B shows a case where the camera microcomputer 205 transmits a command CMD1 requesting data transmission to the lens microcomputer 111 and receives 2-byte lens data DT1 (DT1a, DT1b) corresponding to the command CMD1. The signal waveform is shown. FIG. 3B shows an example in which data communication is executed in response to “command CMD1”.

  Between the camera microcomputer 205 and the lens microcomputer 111, the type of lens data DT and the number of bytes corresponding to each of a plurality of types of commands are determined in advance. When the camera microcomputer 205, which is a communication master, transmits a specific command to the lens microcomputer 111, the lens microcomputer 111 transmits a necessary number of clocks to the camera microcomputer 205 based on information on the number of lens data bytes corresponding to the command. Further, the processing of the lens microcomputer 111 for the command CMD1 includes superimposing the BUSY signal on the clock signal LCLK of each frame, and the above-described BUSY frame is inserted between the data frames.

  With the command CMD1, the camera microcomputer 205 transmits a clock signal LCLK to the lens microcomputer 111, and further transmits a command CMD1 requesting transmission of lens data DT1 to the lens microcomputer 111 as a camera data signal DCL. The lens data signal DLC in this frame is treated as invalid data.

  Subsequently, the camera microcomputer 205 switches the clock channel on the camera microcomputer side (camera main body side) from the output setting to the input setting after outputting the clock signal LCLK for 8 cycles on the clock channel. When the switching of the clock channel on the camera microcomputer side is completed, the lens microcomputer 111 switches the clock channel on the lens microcomputer 111 side (interchangeable lens side) from the input setting to the output setting. Then, the lens microcomputer 111 sets the voltage level of the clock channel to Low in order to notify the camera microcomputer 205 of the communication standby request BUSY. Thereby, the BUSY signal is superimposed on the clock channel. The camera microcomputer 205 maintains the input setting of the clock channel and stops communication with the lens microcomputer 111 during a period when the communication standby request BUSY is notified.

  The lens microcomputer 111 generates lens data DT1 corresponding to the command CMD1 during the notification period of the communication standby request BUSY. When the preparation for transmitting the lens data DT1 as the lens data signal DLC of the next frame is completed, the signal level of the clock channel on the lens microcomputer side is switched to High, and the communication standby request BUSY is canceled.

  When the camera microcomputer 205 recognizes the cancellation of the communication standby request BUSY, the camera microcomputer 205 transmits the one-frame clock signal LCLK to the lens microcomputer 111 to receive the lens data DT1a from the lens microcomputer 111. When the camera microcomputer 205 and the lens microcomputer 111 repeat the same operation as described above, the camera microcomputer 205 receives the lens data DT1b from the lens microcomputer 111.

  FIG. 3C shows a case where the camera microcomputer 205 transmits a command CMD2 for requesting data transmission to the lens microcomputer 111 and receives 3-byte lens data DT2 (DT2a to DT2c) corresponding thereto from the lens microcomputer 111. The signal waveform is shown. FIG. 3C shows an example in which data communication is executed in response to the command CMD2. The processing of the lens microcomputer 111 for the command CMD2 in the command CMD2 includes superimposing the BUSY signal on the clock channel only in the first frame. That is, the lens microcomputer 111 does not superimpose the BUSY signal in the subsequent second to fourth frames.

  Thereby, the BUSY frame is not inserted between the second to fourth frames, and the waiting period between the frames can be shortened. However, during a period when no BUSY frame is inserted, the lens microcomputer 111 cannot send a communication standby request to the camera microcomputer 205. For this reason, it is necessary to determine the number of data to be transmitted, the transmission interval, the priority order of communication processing in the lens microcomputer 111, and the like so as not to cause communication failure.

  Next, communication in communication method B will be described. FIG. 4 shows a waveform of a communication signal exchanged between the camera microcomputer 205 and the lens microcomputer 111 in the communication method B.

  In the communication system B, the transmission request channel is used for notification of a transmission request of lens data from the camera microcomputer 205 as a communication master to the lens microcomputer 111 as a communication slave. Notification on the transmission request channel is performed by switching the signal level (voltage level) between the High (first level) and Low (second level) on the transmission request channel. In the following description, a signal supplied to the transmission request channel in the communication method B is referred to as a transmission request signal RTS.

  The first data communication channel is used to transmit a lens data signal DLC including various data from the lens microcomputer 111 to the camera microcomputer 205, as in the communication method A. Similarly to the communication method A, the second data communication channel is also used for transmission of the camera data signal DCL including a control command, a transmission request command, and the like from the camera microcomputer 205 to the lens microcomputer 111.

  In the communication method B, unlike the communication method A, the camera microcomputer 205 and the lens microcomputer 111 do not transmit / receive data in synchronization with a common clock signal, but set a communication speed in advance and perform communication based on this setting. Send and receive at bit rate. The communication bit rate indicates the amount of data that can be transferred in one second, and the unit is represented by bps (bit per second).

  In the present embodiment, also in the communication method B, as in the communication method A, the camera microcomputer 205 and the lens microcomputer 111 communicate with each other by a full-duplex communication method (full duplex method) in which transmission and reception are performed.

  FIG. 4A shows a signal waveform of one frame which is the minimum communication unit. The breakdown of the data format of one frame is partially different between the camera data signal DCL and the lens data signal DLC.

  First, the data format of the lens data signal DLC will be described. One frame of the lens data signal DLC is composed of the first half data frame and the BUSY frame that follows it. The lens data signal DLC is maintained at a high signal level when data transmission is not performed.

  The lens microcomputer 111 sets the voltage level of the lens data signal DLC to LOW for one bit period in order to notify the camera microcomputer 205 of the start of transmission of one frame of the lens data signal DLC. This one bit period is called a start bit ST, and a data frame is started from the start bit ST. Subsequently, the lens microcomputer 111 transmits 1-byte lens data in an 8-bit period from the second bit to the ninth bit following the start bit ST.

  The bit arrangement of the data is MSB (Most Significant Bit) first format, starting with the most significant data D7, followed by the data D6 and the data D5 in order, and ending with the least significant data D0. Then, the lens microcomputer 111 adds 1-bit parity information (PA) to the 10th bit, and sets the voltage level of the lens data signal DLC to High during the stop bit SP indicating the end of one frame. Thereby, the data frame started from the start bit ST is completed. Note that the parity information does not need to be 1 bit, and a plurality of bits of parity information may be added. Further, parity information is not essential, and a format to which no parity information is added may be used.

  Subsequently, as indicated by “DLC (with BUSY)” in the drawing, the lens microcomputer 111 adds a BUSY frame after the stop bit SP. The BUSY frame represents the period of the communication standby request BUSY notified from the lens microcomputer 111 to the camera microcomputer 205 as in the communication method A. The lens microcomputer 111 holds the signal level of the lens data signal DLC at Low until the communication standby request BUSY is canceled.

  On the other hand, notification of the communication standby request BUSY from the lens microcomputer 111 to the camera microcomputer 205 may be unnecessary. For this case, as shown by “DLC (without BUSY)” in the figure, a data format that forms one frame without adding a BUSY frame (hereinafter also referred to as BUSY notification) is also provided. That is, the data format of the lens data signal DLC can be selected from those with or without the BUSY notification depending on the processing status on the lens microcomputer side.

  A method for identifying the presence or absence of BUSY notification performed by the camera microcomputer 205 will be described. The signal waveform shown in “DLC (without BUSY)” and the signal waveform shown in “DLC (with BUSY)” in FIG. 4A include bit positions B1 and B2. The camera microcomputer 205 selects one of these bit positions B1 and B2 as the BUSY identification position P for identifying the presence or absence of the BUSY notification. As described above, this embodiment employs a data format for selecting the BUSY identification position P from the bit positions of B1 and B2. Thus, it is possible to cope with the problem that the processing time until the BUSY notification (DLC Low) is determined after the data frame transmission of the lens data signal DLC is determined depending on the processing performance of the lens microcomputer 111.

  Whether the BUSY identification position P is set to the bit position of B1 or the bit position of B2 is determined by communication between the camera microcomputer 205 and the lens microcomputer 111 before performing communication in the communication method B. The BUSY identification position P does not need to be fixed at any one of the bit positions B1 and B2, and may be changed according to the processing capabilities of the camera microcomputer 205 and the lens microcomputer 111. The BUSY identification position P is not limited to B1 and B2, and can be set to a predetermined position after the stop bit SP.

  Here, the reason why the BUSY frame added to the clock signal LCLK in the communication method A is the data format added to the lens data signal DLC in the communication method B will be described.

  In the communication method A, it is necessary to exchange the clock signal LCLK output from the camera microcomputer 205 serving as the communication master and the BUSY signal output from the lens microcomputer 111 serving as the communication slave using the same clock channel. For this reason, the collision between the outputs of the camera microcomputer 205 and the lens microcomputer 111 is prevented by the time division method. That is, it is possible to prevent collision between outputs by appropriately assigning the output possible period of the camera microcomputer 205 and the lens microcomputer 111 in the clock channel.

  However, in this time division method, it is necessary to reliably prevent the outputs of the camera microcomputer 205 and the lens microcomputer 111 from colliding with each other. Therefore, the output of both microcomputers 205 and 111 is prohibited from the time when the camera microcomputer 205 completes the output of the 8-pulse clock signal LCLK until the time when the lens microcomputer 111 is allowed to output the BUSY signal. The output prohibition period is inserted. This output prohibition period is a communication invalid period during which the camera microcomputer 205 and the lens microcomputer 111 cannot communicate with each other, which causes a reduction in effective communication speed.

  In order to solve such a problem, in the communication method B, a data format for adding a BUSY frame from the lens microcomputer 111 to the lens data signal DLC in the first data communication channel which is a dedicated output channel of the lens microcomputer 111 is used. Adopted.

  The specification of the data frame of the camera data signal DCL is the same as that of the lens data signal DLC. However, unlike the lens data signal DLC, the camera data signal DCL is prohibited from adding a BUSY frame.

  Next, a communication procedure using the communication method B between the camera microcomputer 205 and the lens microcomputer 111 will be described. First, when an event for starting communication with the lens microcomputer 111 occurs, the camera microcomputer 205 sets the voltage level of the transmission request signal RTS to Low (hereinafter also referred to as asserting the transmission request signal RTS), whereby the lens microcomputer 111. A communication request is notified. The event here means, for example, that the user operates a release switch (not shown).

  When the lens microcomputer 111 detects a communication request because the voltage level of the transmission request signal RTS has changed to Low, the lens microcomputer 111 generates a lens data signal DLC to be transmitted to the camera microcomputer 205. When the lens data signal DLC is ready for transmission, transmission of the lens data signal DLC for one frame is started via the first data communication channel. Here, the lens microcomputer 111 starts transmitting the lens data signal DLC within a set time set between the camera microcomputer 205 and the lens microcomputer 111 from the time when the voltage level of the transmission request signal RTS becomes Low. To do.

  That is, in the communication method B, lens data to be transmitted may be determined from the time when the voltage level of the transmission request signal RTS becomes Low until the transmission of the lens data signal DLC is started. Since there is no strict restriction that the lens data to be transmitted needs to be determined by the time when the first clock pulse is input as in the communication method A, there is a degree of freedom in the timing of starting transmission of the lens data signal DLC. Can be given.

  Next, the camera microcomputer 205 returns the voltage level of the transmission request signal RTS to High in response to detection of the start bit ST added to the head of the lens data signal DLC received from the lens microcomputer 111 (hereinafter referred to as transmission request signal RTS). Is also negated). This cancels the transmission request and starts transmission of the camera data signal DCL on the second communication channel. Note that either the negation of the transmission request signal RTS or the transmission start of the camera data signal DCL may be first, and these may be performed before the reception of the data frame of the lens data signal DLC is completed.

  The lens microcomputer 111 that has transmitted the data frame of the lens data signal DLC adds a BUSY frame to the lens data signal DLC when it is necessary to notify the camera microcomputer 205 of a communication standby request BUSY. The camera microcomputer 205 monitors the presence / absence of a communication standby request BUSY and is prohibited from asserting the transmission request signal RTS for the next transmission request while the communication standby request BUSY is being notified.

  The lens microcomputer 111 executes processing necessary during a period in which communication from the camera microcomputer 205 is awaited by the communication standby request BUSY, and cancels the communication standby request BUSY after the next communication preparation is completed. The camera microcomputer 205 is permitted to assert the transmission request signal RTS for the next transmission request on condition that the communication standby request BUSY is canceled and the transmission of the data frame of the camera data signal DCL is completed. .

  Thus, in this embodiment, the lens microcomputer 111 sends the data frame of the lens data signal DLC to the camera microcomputer 205 in response to the transmission request signal RTS being asserted by a communication start event in the camera microcomputer 205 as a trigger. Start sending. Then, the camera microcomputer 205 starts transmitting the data frame of the camera data signal DCL to the lens microcomputer 111 in response to detecting the start bit ST of the lens data signal DLC.

  Here, if necessary, the lens microcomputer 111 adds a BUSY frame after the data frame of the lens data signal DLC for the communication standby request BUSY, and then cancels the communication standby request BUSY so that one frame of communication processing is performed. Complete. Through this communication process, 1-byte communication data is transmitted and received between the camera microcomputer 205 and the lens microcomputer 111.

  FIG. 4B shows a signal waveform when communication is continuously performed in the data format shown in “DLC (with BUSY)” of FIG. The communication standby request BUSY (BUSY frame) from the lens microcomputer 111 is notified using the lens data signal DLC in the first data communication channel, and the next communication is started after the communication standby request BUSY is canceled. CMD1 shown in FIG. 4B indicates a transmission request command transmitted from the camera microcomputer 205 to the lens microcomputer 111 as a camera data signal DCL. In response to receiving this transmission request command CMD1, the lens microcomputer 111 transmits a 2-byte lens data signal DT1 (DT1a, DT1b) corresponding to the command CMD1 to the camera microcomputer 205.

  In the example of FIG. 4C, communication is first performed in the data format “BUSY present”, and then communication is performed in the data format “BUSY absent”. CMD2 indicates a control command and a transmission request command transmitted from the camera microcomputer 205 to the lens microcomputer 111 as a camera data signal DCL. In the figure, the control command and the transmission request command are transmitted in one frame, but the control command and the transmission request command may be transmitted in separate frames. The lens microcomputer 111 switches the data format from “with BUSY” to “without BUSY” in response to receiving the control command of the command CMD2. In response to receiving the transmission request command of the command CMD2, the lens microcomputer 111 transmits a 3-byte lens data signal DT2 (DT2a to DT2c) corresponding to the transmission request command to the camera microcomputer 205.

  Next, a procedure for determining a communication method of communication performed between the camera microcomputer 205 and the lens microcomputer 111 will be described with reference to FIG. The camera microcomputer 205 and the lens microcomputer 111 perform communication control shown in FIG. 5 according to a communication control program that is a computer program. In the figure, “S” means a step.

  First, when the interchangeable lens 100 is attached to the camera body 200, in S100 and S200, the camera microcomputer 205 and the lens microcomputer 111 set the communication format to an initial communication format in which establishment of communication is guaranteed. “Communication format” is a communication specification defined by a combination of a communication method and a data format. In this embodiment, the communication method A is used as the communication method in the initial communication format.

  Subsequently, in S101, the camera microcomputer 205 transmits camera identification information representing a communication format compatible with the camera body 200 to the lens microcomputer 111, and the lens microcomputer 111 acquires the camera identification information. In step S <b> 202, the lens microcomputer 111 transmits lens identification information indicating a communication format compatible with the interchangeable lens 100 to the camera microcomputer 205, and the camera microcomputer 205 receives the lens identification information.

  Here, the “identification information” includes information indicating whether the communication method B is supported in addition to the communication method A, and information indicating the range of communication bit rates that can be supported. Information indicating the BUSY identification position P is also included in the identification information.

  The camera microcomputer 205 receives the lens identification information in S102. The lens microcomputer 111 receives camera identification information in S201. Here, in the flowchart of FIG. 5, the lens identification information is transmitted after the camera identification information is transmitted. However, the camera identification information may be transmitted after the lens identification information is transmitted.

  Subsequently, in S103 and S203, the communication format is set in the subsequent communication. Specifically, when the interchangeable lens attached to the camera body 200 can communicate with the communication method B, the camera microcomputer 205 and the lens microcomputer 111 change the communication method from the communication method A to the communication method B. In addition, the camera microcomputer 205 and the lens microcomputer 111 determine the fastest rate as a communication bit rate within a range that can correspond to each other. In addition, the position closest to the stop bit SP among the BUSY identification positions that can correspond to each other is set as the BUSY identification position.

  Next, the switching procedure from the communication method A to the communication method B will be described with reference to FIG. FIG. 6 shows waveforms of communication signals exchanged between the camera microcomputer 205 and the lens microcomputer 111 before and after switching from the communication method A to the communication method B. In switching from the communication method A to the communication method B, the camera microcomputer 205 changes the setting of the camera communication unit 208 from the first setting corresponding to the communication method A to the second setting corresponding to the communication method B. Similarly, the lens microcomputer 111 changes the communication setting of the lens communication unit 112 from the first setting corresponding to the communication method A to the second setting corresponding to the communication method B.

  At the switching timing X shown in FIG. 6, the switching of communication settings between the camera microcomputer 205 and the lens microcomputer 111 is completed, and thereafter, communication using the communication method B is performed. As described above, the notification channel functions as a clock channel in the communication method A and functions as a transmission request channel in the communication method B.

  In this embodiment, the lens microcomputer 111 which is a communication slave in the communication method A changes to the second setting corresponding to the communication method B before the camera microcomputer 205 which is a communication master.

  Switching of the communication method is performed according to an instruction from the camera microcomputer 205. The camera microcomputer 205 transmits a notification of switching from the communication method A to the communication method B to the lens microcomputer 111 via the second data communication channel by communication using the communication method A. This switching notification is included in the data frame. The lens microcomputer 111 that has received the switching notification notifies the camera microcomputer 205 of the communication standby request BUSY by superimposing the BUSY signal on the clock channel. Then, while notifying the camera microcomputer 205 of the communication standby request BUSY, the communication setting of the lens microcomputer 111 is changed from the first setting corresponding to the communication method A to the second setting corresponding to the communication method B. .

  When the switching of the communication method in the lens microcomputer 111 is completed, the lens microcomputer 111 cancels the communication standby request BUSY, thereby giving a completion notification to notify the camera microcomputer 205 that the switching of the communication method has been completed. Thereafter, the lens microcomputer 111 monitors whether or not the transmission request signal RTS is notified in the communication method B.

  When the communication waiting request BUSY is canceled, the camera microcomputer 205 changes the communication setting of the camera microcomputer 205 from the first setting corresponding to the communication method A to the second setting corresponding to the communication method B, B is monitored for occurrence of a communication event. The timing when the switching to the communication method B in the camera microcomputer 205 is completed is the switching timing X shown in FIG. After the switching timing X, data communication by the communication method B is executed as described with reference to FIG.

  As described above, in the present invention, the lens microcomputer 111 as a communication slave changes from the first setting to the second setting prior to the camera microcomputer 205 as a communication master. Since it is unclear whether or not the lens microcomputer 111 can immediately execute the change to the second setting, the camera microcomputer 205 confirms the change to the second setting in the lens microcomputer 111, and then The change from the first setting to the second setting is executed.

  When the change to the second setting in the camera microcomputer 205 is executed without confirming that the change to the second setting in the lens microcomputer 111 has been executed, the communication method between the interchangeable lens 100 and the camera body 200 is changed. There is a risk that communication between the two may not be established. In the present invention, after confirming the change to the second setting in the lens microcomputer 111, the camera microcomputer 205 executes the change from the first setting to the second setting. Can be prevented.

  The lens microcomputer 111 changes the communication setting of the lens microcomputer 111 from the first setting to the second setting while notifying the camera microcomputer 205 of the communication standby request BUSY. As a result, the communication setting can be changed in a state where the clock signal CLK is not output from the camera microcomputer 205, and a situation where a communication collision occurs between the camera microcomputer 205 and the lens microcomputer 111 is avoided. Can do.

  The lens microcomputer 111 does not necessarily need to switch the communication method in response to the notification of switching from the communication method A to the communication method B, and may be able to refuse the switching of the communication method. For example, after receiving the switching notification from the camera microcomputer 205, a notification indicating that the switching of the communication method is rejected is transmitted via the first data communication channel. The camera microcomputer 205 that has received this can continue communication with the lens microcomputer 111 in the communication method A without changing the communication setting. Thereby, when the lens microcomputer 111 cannot immediately execute the change to the second setting, the camera microcomputer 205 returns to the first setting again immediately after executing the change from the first setting to the second setting. It is possible to avoid the situation where the change of the above has to be executed.

  Next, switching of the power state in the interchangeable lens 100 will be described. As described above, the interchangeable lens 100 according to the present embodiment receives the first power state and the second power that consumes less power than the first power state in response to receiving a predetermined signal from the camera microcomputer 205. You can switch between states.

  FIG. 7 shows a processing method when switching from the first power state to the second power state and switching from the second power state to the first power state in the interchangeable lens 100. Note that the processing method shown in FIG. 7 starts from a state where the interchangeable lens 100 is in the first power state.

  First, the flow on the camera body 200 side will be described. When an event for causing the interchangeable lens 100 to shift from the first power state to the second power state occurs in the camera body 200, the camera microcomputer 205 causes a command to shift to the second power state (hereinafter referred to as a sleep command). Is transmitted (S300). The sleep command is transmitted / received according to the communication protocol shown in FIG. 3 when the current communication method is communication method A, and is transmitted / received according to the communication protocol shown in FIG. 4 when the current communication method is communication method B.

  In the present embodiment, the camera-side setting unit 206 is a communication method for transmitting a command (hereinafter referred to as a sleep release command) for shifting the interchangeable lens 100 from the second power state to the first power state. Set the same communication method as when the sleep command was sent.

  In step S <b> 301, the camera microcomputer 205 determines whether the current communication method is the communication method A. When the current communication method is the communication method A, the process proceeds to S302, and the communication method when the sleep release command is transmitted next is set to the communication method A.

  If the current communication method determined in S301 is not the communication method A, the process proceeds to S303, and the communication method for transmitting the sleep release command to the lens microcomputer 111 is set to the communication method B.

  After setting the communication method for transmitting the sleep release command next in S302 or S303, if an event occurs in the camera body 200 that causes the interchangeable lens to transition from the second power state to the first power state, the process proceeds to S304. move on. In step S304, the camera microcomputer 205 transmits a sleep release command to the lens microcomputer 111 using the communication method set in step S302 or S303.

  Next, the flow on the interchangeable lens 100 side will be described. When the lens microcomputer 111 receives a sleep command from the camera microcomputer 205 in S400, the process proceeds to S401.

  In the present embodiment, when the lens microcomputer 111 receives the sleep command, the lens side setting unit 114 sets the same communication method as when the sleep command is received as the communication method for the next communication with the camera body. First, in S401, the lens microcomputer 111 determines whether or not the current communication method is the communication method A. If the current communication method is communication method A, the process proceeds to S402. In S402, the lens-side setting unit 114 sets the communication method when receiving the sleep release command to the communication method A, and the power control unit 113 changes the power state of the interchangeable lens 100 from the first power state to the second power state. Switch to.

  In this case, the camera side setting unit 206 sets the communication method for transmitting the sleep release command to the communication method B in S302. Therefore, the communication method used when the lens microcomputer 111 receives the sleep release command is the same as the communication method used when the camera microcomputer 205 transmits the sleep release command. Therefore, the interchangeable lens 100 can appropriately switch the power state according to an instruction from the camera microcomputer 205. When the camera microcomputer 205 transmits a sleep release command to the lens microcomputer 111, the power control unit 113 switches the power state of the interchangeable lens 100 from the second power state to the first power state using the falling edge of the clock signal LCLK as a trigger ( S404). After switching to the first power state is completed, the lens microcomputer 111 communicates with the camera microcomputer 205 in accordance with the communication protocol of communication method A.

  On the other hand, if the current communication method determined in S401 is not the communication method A, the process proceeds to S403. In S403, the lens-side setting unit 114 sets the communication method for receiving the sleep release command to the communication method B, and the power control unit 113 changes the power state of the interchangeable lens 100 from the first power state to the second power state. Switch to.

  In this case, the camera side setting unit 206 sets the communication method for transmitting the sleep release command to the communication method B in S303. Therefore, the communication method used when the lens microcomputer 111 receives the sleep release command is the same as the communication method used when the camera microcomputer 205 transmits the sleep release command. Therefore, the interchangeable lens 100 can appropriately switch the power state according to an instruction from the camera microcomputer 205. When the camera microcomputer 205 transmits a sleep release command to the lens microcomputer 111, the power control unit 113 switches the power state of the interchangeable lens 100 from the second power state to the first power state using the falling edge of the transmission request RTS as a trigger ( S404). After the switching to the first power state is completed, the lens microcomputer 111 communicates with the camera microcomputer 205 according to the communication protocol of communication method B.

  As described above, the power state can be appropriately switched by setting in advance the communication method of communication performed when switching from the second power state to the first power state. In addition, communication can be appropriately performed after the sleep is canceled.

  Further, in this embodiment, the camera side setting unit 206 and the lens side setting unit 114 change the communication method so that the communication method when transmitting and receiving the sleep release command is the same as the communication method when transmitting and receiving the sleep command. It is set. For this reason, even if the lens microcomputer 111 erroneously recognizes a communication command that is not a sleep command due to the influence of noise or the like and switches to the second power state, the first communication command that is transmitted next The power state can be switched to. Accordingly, noise resistance to the channel can also be improved.

[Example 2]
Next, a communication control method in the accessory device and the imaging device according to the second embodiment of the present invention will be described.

  The interchangeable lens as the accessory device and the camera body as the imaging device of this embodiment have the same configuration as the interchangeable lens 100 and the camera body 200 of Embodiment 1 shown in FIG. In the present embodiment, unlike the first embodiment, the communication method for transmitting / receiving the sleep release command is set to the same communication method as that for the initial communication format, regardless of the communication method for transmitting / receiving the sleep command. Note that the communication method of the initial communication format in the present embodiment is the communication method A as in the first embodiment.

  FIG. 8 shows a processing method when switching from the first power state to the second power state and switching from the second power state to the first power state in the interchangeable lens 100. Note that the processing method shown in FIG. 8 starts from a state in which the interchangeable lens 100 is in the first power state.

  First, the flow on the camera body 200 side will be described. When an event for causing the interchangeable lens 100 to shift from the first power state to the second power state occurs in the camera body 200, the camera microcomputer 205 transmits a sleep command to the lens microcomputer 111 (S500). This command is transmitted / received according to the communication protocol shown in FIG. 3 if the current communication method is communication method A, and is transmitted / received according to the communication protocol shown in FIG. 4 if the current communication method is communication method B.

  In step S <b> 501, the camera side setting unit 206 next sets the communication method for transmitting the sleep release command to the communication method A.

  After setting the communication method for transmitting the sleep release command next in S501, if an event for causing the interchangeable lens to shift from the second power state to the first power state occurs in the camera body 200, the process proceeds to S502. In step S <b> 502, the camera microcomputer 205 transmits a sleep release command to the lens microcomputer 111 using the communication method A that is the communication method set in step S <b> 501.

  Next, the flow on the interchangeable lens 100 side will be described. When the lens microcomputer 111 receives a sleep command from the camera microcomputer 205 in S600, the process proceeds to S601.

  In step S601, the communication method for receiving the sleep release command is set to communication method A, and the power control unit 113 switches the power state of the interchangeable lens 100 from the first power state to the second power state.

  As described above, in this embodiment, the camera side setting unit 206 sets the communication method when transmitting the sleep release command to the communication method A in S501. Therefore, the communication method when the lens microcomputer 111 receives the sleep release command and the communication method when the camera microcomputer 205 transmits the sleep release command are the same. For this reason, the interchangeable lens 100 can appropriately switch the power state according to an instruction from the camera microcomputer 205.

  When the camera microcomputer 205 transmits a sleep release command to the lens microcomputer 111, the power control unit 113 switches the power state of the interchangeable lens 100 from the second power state to the first power state using the falling edge of the clock signal LCLK as a trigger ( S602). After switching to the first power state is completed, the lens microcomputer 111 communicates with the camera microcomputer 205 in accordance with the communication protocol of communication method A.

  As described above, the power state is appropriately switched by setting in advance the communication method of communication performed between the interchangeable lens 100 and the camera body 200 when the first power state is switched to the second power state. It can be performed. In addition, communication can be appropriately performed after the sleep is canceled.

  In the first embodiment, the example in which the communication method for transmitting and receiving the sleep release command is changed according to the communication method for transmitting and receiving the sleep command has been described. In this case, it is necessary to prepare a processing flow corresponding to each of the communication method A and the communication method B as a processing flow for canceling the sleep.

  On the other hand, in this embodiment, the camera side setting unit 206 and the lens side setting unit 114 do not depend on the communication method at the time of transmitting / receiving the sleep command, but the communication method at the time of transmitting / receiving the sleep release command is the initial communication format The communication method A is set to be the same as the communication method. Thereby, the processing flow for canceling sleep can be made common with the processing flow when the interchangeable lens 100 is attached to the camera body 200 shown in FIG. That is, according to the present embodiment, it is possible to simplify the process at the time of sleep release.

  The embodiments described above are merely representative examples, and various modifications and changes can be made to the embodiments when the present invention is implemented. For example, in the above-described embodiment, an example in which an interchangeable lens is used as an accessory device has been shown.

100 Interchangeable lens (accessory device)
113 Power control unit 114, 206 Setting unit 200 Camera body (imaging device)

Claims (13)

An accessory device that is detachably attached to the imaging device and can communicate with the imaging device by a plurality of communication methods,
Switching between a first power state communicable with the imaging device and a second power state with lower power consumption than the first power state in response to receiving a signal transmitted from the imaging device A power control unit;
A setting unit for setting a communication method of communication performed with the imaging device when the second power state is switched to the first power state;
An accessory device comprising:   The setting unit can switch a communication method of communication performed with the imaging device when the second power state is switched to the first power state from the first power state to the second power state. The accessory device according to claim 1, wherein the communication device is set to the same communication method as the communication method performed with the imaging device. When the accessory device is attached to the imaging device, the accessory device performs initial communication to transmit information about a communication method supported by the accessory device to the imaging device,
The setting unit sets a communication method of communication performed with the imaging apparatus when the second power state is switched to the first power state to the same communication method as the communication method of the initial communication. The accessory device according to claim 1. A notification channel used for notification, and
A first data communication channel used for data transmission from the accessory device to the imaging device;
Communicating with the imaging device using a second data communication channel used for data transmission from the imaging device to the accessory device;
The accessory device is a communication method corresponding to a first communication method, which is a clock synchronous communication method synchronized with a clock signal, and a start-stop synchronous communication method for communication performed with the imaging device. Switchable between the second communication method and
When communicating with the imaging device using the first communication method, a communication standby request for preventing data transmission from the imaging device to the accessory device is made via the notification channel. Notify the imaging device,
The communication standby request is notified to the imaging apparatus via the first data communication channel when communicating with the imaging apparatus using the second communication method. The accessory apparatus of any one of Claims.   5. The communication waiting request is transmitted to the imaging apparatus via the first data communication channel when communicating with the imaging apparatus using the second communication method. 6. Accessory device. In a state where communication with the imaging apparatus is performed using the first communication method, when the signal for switching the communication method is received from the imaging apparatus, the accessory device notifies the imaging apparatus of the communication standby request. And
The accessory device according to claim 4, wherein the accessory device switches a communication method while notifying the communication standby request.   The accessory device performs a completion notification indicating that the switching is completed to the imaging device in response to the switching from the first communication method to the second communication method being completed. Item 7. The accessory device according to any one of Items 4 to 6.   The accessory device according to claim 7, wherein the completion notification is performed by canceling the communication standby request. An accessory device is detachably mounted and is an imaging device capable of communicating with the accessory device by a plurality of communication methods,
The accessory device receives a signal transmitted from the imaging device, a first power state that can communicate with the imaging device, and a second power that consumes less power than the first power state State can be switched,
The imaging apparatus includes a setting unit that sets a communication method for transmitting a signal for switching the power state of the accessory device from the second power state to the first power state to the accessory device. An imaging apparatus characterized by the above.   The setting unit sets a communication method of a signal to be transmitted to the accessory device to switch the power state of the accessory device from the second power state to the first power state, and sets the power state of the accessory device. The imaging apparatus according to claim 9, wherein the imaging apparatus is set to the same communication system as a communication system of a signal transmitted to the accessory device in order to switch from the first power state to the second power state. When the accessory device is attached to the imaging device, the imaging device performs initial communication to acquire information on the communication method supported by the accessory device from the accessory device,
The setting unit uses a communication method of a signal transmitted to the accessory device to switch the power state of the accessory device from the second power state to the first power state, the same as the communication method of the initial communication. The imaging apparatus according to claim 1, wherein the imaging apparatus is set to a communication method. The imaging device is a communication method corresponding to a first communication method, which is a clock synchronous communication method synchronized with a clock signal, and a start-stop synchronous communication method for communication performed with the accessory device. Switchable between the second communication method and
In response to receiving a notification from the accessory device indicating that the switching from the first communication method to the second communication method is completed in the accessory device, the imaging device starts from the first communication method. The imaging apparatus according to claim 9, wherein switching to the second communication method is performed. A notification channel used for notification, and
A first data communication channel used for data transmission from the accessory device to the imaging device;
Communicating with the accessory device using a second data communication channel used for data transmission from the imaging device to the accessory device;
The imaging device is a communication method corresponding to a first communication method, which is a clock synchronous communication method synchronized with a clock signal, and a start-stop synchronous communication method for communication performed with the accessory device. Switchable between the second communication method and
When communicating with the accessory device in the first communication method, the clock signal is transmitted to the accessory device via the notification channel;
When communicating with the accessory device by the second communication method, a transmission request signal for requesting communication from the accessory device to the imaging device is transmitted to the accessory device via the notification channel. The imaging apparatus according to any one of claims 9 to 12, wherein the imaging apparatus is characterized in that

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