JP2018081228A - Lens device, imaging device, and communication control method of lens device and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens device capable of avoiding collision of data and surely switching a communication direction of the data.SOLUTION: A lens device (100) capable of being attached to and detached from an imaging device includes: a communication unit (111a) capable of bidirectional communication with an imaging device (200); a switching circuit (151) for switching a communication direction; and voltage control circuits (152 and 153) for controlling the voltage of the switching circuit to a prescribed voltage at the time of switching the communication direction.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an interchangeable lens capable of communicating with a camera body.

  Transmission of control commands from the camera body to the interchangeable lens and transmission of lens information from the interchangeable lens to the camera body are mutually communicated in an optical device such as a photographing system that includes an interchangeable lens and a camera body. Done through means.

  In moving image capturing and live view display, smooth lens control in accordance with the imaging cycle is required. Therefore, it is necessary to synchronize the imaging timing of the camera body and the control timing of the interchangeable lens, and the camera body acquires lens information necessary for lens control and transmits a control command to the interchangeable lens within the imaging cycle. It needs to be completed. In addition, since the camera body acquires a large amount of image correction data from the interchangeable lens, it is possible to correct the image data with higher accuracy, and thus a large-capacity and short-time data communication is required.

  In Patent Document 1, since a large amount of data is transmitted from the interchangeable lens to the camera body, a data transmission terminal from the camera body to the interchangeable lens can also be used for data transmission from the interchangeable lens to the camera body. A camera system is disclosed.

JP, 2015-121638, A

  However, Patent Document 1 does not describe a method of switching the input / output direction so that data collision does not occur when the input / output direction of the terminal for transmitting data from the camera body to the interchangeable lens is switched. As a result, when the input / output direction is switched, a through current may flow through the semiconductor element and the semiconductor element may be destroyed.

  SUMMARY An advantage of some aspects of the invention is that it provides a lens device, an imaging device, and a lens device and a communication control method for the imaging device that can reliably switch the data communication direction while avoiding data collision.

  A lens apparatus according to an aspect of the present invention is a lens apparatus that can be attached to and detached from an imaging apparatus, a communication unit capable of bidirectional communication with the imaging apparatus, a switching circuit that switches a communication direction, and the communication direction And a voltage control circuit for controlling the voltage of the switching circuit to a predetermined voltage at the time of switching.

  An imaging apparatus as another aspect of the present invention is an imaging apparatus in which a lens apparatus is detachable, a communication unit capable of bidirectional communication with the lens apparatus, a switching circuit that switches a communication direction, and the communication direction And a voltage control circuit for controlling the voltage of the switching circuit to a predetermined voltage.

  A communication control method for a lens apparatus according to another aspect of the present invention is a communication control method for a lens apparatus that can be attached to and detached from an imaging apparatus. The method includes a step of receiving a signal related to switching of a communication method, and a switching of a communication direction. The step of controlling the voltage of the switching circuit including the first buffer and the second buffer to a predetermined voltage, and the switching circuit used for communication in a state where the voltage of the switching circuit is controlled to the predetermined voltage. Switching the buffer from the first buffer to the second buffer, and stopping the voltage control of the switching circuit.

  A communication control method for an imaging apparatus according to another aspect of the present invention is a communication control method for an imaging apparatus in which a lens apparatus is detachable, and includes a step of transmitting a signal related to switching of a communication method and a switching of a communication direction. The step of controlling the voltage of the switching circuit including the first buffer and the second buffer to a predetermined voltage, and the switching circuit used for communication in a state where the voltage of the switching circuit is controlled to the predetermined voltage. Switching the buffer from the first buffer to the second buffer, and stopping the voltage control of the switching circuit.

  Other objects and features of the present invention are illustrated in the following examples.

  According to the present invention, it is possible to provide a lens device, an imaging device, and a lens device and a communication control method for the imaging device that can reliably switch the data communication direction while avoiding data collision.

1 is a block diagram of an imaging system in each embodiment. It is a block diagram of the communication means which communicates between the camera main body in Example 1, 2 and an interchangeable lens. It is explanatory drawing of the communication by the normal communication system in each Example. It is explanatory drawing of the communication by the DLC2ch communication system in each Example. 6 is a timing chart of communication control when the communication method is switched from the normal communication method to the DLC2ch communication method in the first embodiment. 2 is a block diagram of communication means for performing communication between the camera body and the interchangeable lens in Embodiment 1. FIG. In Example 1, it is a flowchart of the communication control at the time of switching a communication system from a normal communication system to a DLC2ch communication system. In Example 2, it is a timing chart of the communication control at the time of switching a communication system from a DLC2ch communication system to a normal communication system. FIG. 10 is a block diagram of communication means for performing communication between a camera body and an interchangeable lens in Embodiment 3.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, an imaging system in Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an imaging system 10 (camera system). The imaging system 10 includes a camera body 200 (imaging device) and an interchangeable lens 100 (lens device) that can be attached to and detached from the camera body 200.

  The camera body 200 and the interchangeable lens 100 transmit control commands, internal information, and the like between the camera body 200 and the interchangeable lens 100 using the mutual communication means. In addition, both communication means support a plurality of communication formats. Depending on the type of data to be communicated and the communication purpose, various communication methods can be synchronized with each other by switching to the same communication format. It is possible to select an optimal communication format corresponding to the situation.

  The interchangeable lens 100 and the camera body 200 are mechanically and electrically connected to each other via a mount 300 that is a coupling mechanism. The interchangeable lens 100 obtains power from the camera body 200 via a power supply terminal (not shown) provided on the mount 300, and is necessary for various actuators and lens microcomputer 111 (lens control means) described later to operate. Supply power. Further, the interchangeable lens 100 and the camera body 200 communicate with each other via a communication terminal unit 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, a diaphragm unit 114 that adjusts the amount of light, an anti-vibration lens 103, and a focus lens 104 that performs focus adjustment. The zoom 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 the direction along the optical axis OA (optical axis direction), and are driven in the optical axis direction by stepping motors 107 and 108. The stepping motors 107 and 108 move (drive) the zoom lens 102 and the focus lens 104 in synchronization with the drive pulse, respectively. The anti-vibration lens 103 shifts in a direction orthogonal to the optical axis OA of the imaging optical system, thereby reducing image blur due to camera shake or the like.

  The lens microcomputer 111 is a lens control unit that controls the operation of each unit in the interchangeable lens 100. The lens microcomputer 111 includes a communication unit 111a, and receives a control command and a transmission request command transmitted from the camera body 200 via the lens communication interface circuit 112 (lens communication I / F unit). The lens microcomputer 111 performs lens control corresponding to the control command, and transmits lens data corresponding to the transmission request command to the camera body 200 via the lens communication interface circuit 112 (and the communication unit 111a). As described above, the lens microcomputer 111 (communication unit 111a) is capable of bidirectional communication with the camera body 200 (camera microcomputer 205). The lens microcomputer 111 outputs control signals to the zoom drive circuit 119 and the focus drive circuit 120 in response to commands related to zoom and focusing among the control commands to drive the stepping motors 107 and 108. Thereby, zoom processing for controlling the zoom operation by the zoom lens 102 and AF (auto focus) processing for controlling the focus adjustment operation by the focus lens 104 are performed.

  The aperture unit 114 includes aperture 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 control signal to the aperture driving 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.

  The lens microcomputer 111 is connected to an anti-vibration device such as a voice coil motor via an anti-vibration drive circuit 125 in accordance with a shake (camera shake) detected by a shake sensor (not shown) such as a vibration gyro provided in the interchangeable lens 100. The vibration actuator 126 is driven. As a result, an image stabilization process for controlling the shift operation (image stabilization operation) of the image stabilization lens 103 is performed. In addition, the lens microcomputer 111 performs control according to a signal (input signal) from an operation instruction unit such as a focus ring 130 provided on the lens barrel of the interchangeable lens 100 and controls the overall operation of the interchangeable lens 100. The rotation amount of the focus ring 130 is detected by a detection unit 131 such as a photo interrupter (PI).

  The camera body 200 includes an image sensor 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 205 (camera control means), and a display unit 206. The image sensor 201 photoelectrically converts a subject image (optical image) formed via 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 processes on the digital signal from the A / D conversion circuit 202 to generate an image signal. The signal processing circuit 203 also generates focus information indicating the contrast state of the subject image (focus state of the imaging optical system) and luminance information indicating the exposure state from the image signal. The signal processing circuit 203 outputs the image signal to the display unit 206. The display unit 206 displays the image signal as a live view image used for checking the composition, the focus state, and the like.

  The camera microcomputer 205 controls the camera body 200 in response to a user input (operation by the user) via the operation unit 207 such as an imaging instruction switch and various setting switches. The camera microcomputer 205 includes a communication unit 205a and relates to a zooming operation of the zoom lens 102 according to the operation of the zoom switch (operation unit 207) via the camera communication interface circuit 208 (camera communication I / F unit). A control command is transmitted to the lens microcomputer 111. Further, the camera microcomputer 205 transmits, via the camera communication interface circuit 208, a control command related to the light amount adjustment operation of the diaphragm unit 114 according to the luminance information and the focus adjustment operation of the focus lens 104 according to the focus information to the lens microcomputer 111. . The camera microcomputer 205 (communication unit 205a) is capable of bidirectional communication with the interchangeable lens 100 (lens microcomputer 111).

  Next, referring to FIG. 2, communication means (communication circuit) for performing communication between the camera body 200 (camera microcomputer 205) and the interchangeable lens 100 (lens microcomputer 111), and communication performed by the communication means. Processing (communication control method) will be described. The camera microcomputer 205 functions as a communication mode management unit and a transmission request unit. The lens microcomputer 111 functions as lens data generation means and data transmission means.

  FIG. 2 is a block diagram of communication means for performing communication between the camera microcomputer 205 and the lens microcomputer 111. The camera microcomputer 205 and the lens microcomputer 111 communicate via a communication terminal unit provided on the mount 300 described above. The camera communication interface circuit 208 and the lens communication interface circuit 112 have switching circuits 218 and 151 for selectively communicating the camera data signal DCL and the second lens data signal DLC2 (switching the communication direction), respectively. Each of the switching circuits 218 and 151 includes a first buffer 218a and 151a and a second buffer 218b and 151b (parallel switching buffers) provided in parallel so that the signal output direction (communication direction) can be switched. I / O buffer). Each buffer (the first buffer 218a and the second buffer 218b, or the first buffer 151a and the second buffer 151b) in each of the switching circuits 218 and 151 is exclusively selected. With such a circuit configuration, the communication line (third communication line) of the camera data signal DCL is sent through the communication line of the second lens data signal DLC2 that transmits data from the interchangeable lens 100 to the camera body 200 by switching the communication direction. Can be used as Therefore, communication of the first lens data signal DLC and the second lens data signal DLC2 transmitted from the interchangeable lens 100 to the camera body 200 using two communication lines (second communication line and third communication line). Is possible. Hereinafter, this communication method is referred to as a DLC2ch communication method, and details will be described later.

  Next, a communication method that is 3-wire asynchronous serial communication will be described. The communication request signal CTS (first signal) is transmitted from the camera microcomputer 205 as the communication master to the lens microcomputer 111 as the slave via the first communication line. The communication signal DCL (third signal) includes a control command, a transmission request command, and the like, and is transmitted from the camera microcomputer 205 to the lens microcomputer 111 via the third communication line. The data signal DLC (second signal) includes lens data and the like, and is transmitted from the lens microcomputer 111 to the camera microcomputer 205. The camera microcomputer 205 and the lens microcomputer 111 preliminarily define the communication speed of mutual communication, and perform transmission / reception at a communication bit rate that complies with the prescription. The communication bit rate is the amount of data that can be transferred per second, and its unit is expressed in bps (bits per second).

  Next, with reference to FIG. 3, a communication method in which data is mutually communicated between the camera body 200 and the interchangeable lens 100 will be described. Hereinafter, this communication method is referred to as a normal communication method. FIG. 3 is an explanatory diagram of communication (first communication) by the normal communication method, and shows a waveform of a communication signal of one frame which is the minimum communication unit.

  The breakdown of the data format of one frame is different in part between the data signal DCL and the data signal DLC, and the difference will be described below. First, the data format of the data signal DLC will be described. As a major division, one frame is composed of a first half data frame followed by a BUSY frame. As a steady state, the signal level is maintained in a HIGH state in a non-transmission state in which data transmission is not performed. Subsequently, in order to notify the camera microcomputer 205 on the data receiving side of the start of communication of DLC data, the start of transmission of one frame is notified by setting the signal level to the LOW level for one bit period. This one bit period is called a start bit ST, and a data frame is started from this bit.

  Subsequently, 1-byte lens data is transmitted in an 8-bit period from the second bit to the ninth bit. The bit arrangement of data starts from the most significant data D7 in the MSB first format, continues to the data D6 and the data D5 in order, and ends with the least significant data D0. Subsequently, after 1-bit parity PA information is added to the 10th bit, the DLC signal level is set to HIGH during the period of the stop bit SP indicating the end of one frame. Thereby, the data frame period started from the start bit ST ends. Subsequently, a BUSY frame is added after the stop bit SP. The BUSY frame represents a communication standby request period notified from the lens microcomputer 111 to the camera microcomputer 205, and holds the signal level at the LOW level until the communication standby factor is canceled.

  Next, the data format of the data signal DCL will be described. Since the data signal DCL and the data signal DLC have the same data frame specifications, detailed description thereof is omitted. The data signal DCL is different from the format of the data signal DLC in that addition of a BUSY frame is prohibited.

  Next, communication flow control, which is a communication procedure performed 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 notifies the lens microcomputer 111 of a communication request by setting the communication request signal CTS to LOW level (that is, asserts the CTS signal). To do). When the lens microcomputer 111 detects a communication request based on the LOW level of the communication request signal CTS, the lens microcomputer 111 generates DLC data to be transmitted to the camera microcomputer 205. Then, after preparation for data transmission is completed, the lens microcomputer 111 starts transmission of lens data of one frame by the data signal DLC. Here, during the period from the time when the communication request signal CTS becomes the LOW level to the start of the transmission of the DLC data, the DLC data transmission is performed within a specified time determined between the camera microcomputer 205 and the lens microcomputer 111. Just start.

  Subsequently, after detecting the start bit ST at the head of the DLC data frame transmitted from the lens microcomputer 111, the camera microcomputer 205 returns the communication request signal CTS to HIGH. Accordingly, the camera microcomputer 205 performs processing for canceling the communication request (negotiation of the CTS signal) and DCL data transmission start processing, and performs DCL data transmission. There is no restriction on the order of these two processes, and the two processes may be performed until the transmission of the lens data DLC data frame is completed.

  Subsequently, after transmitting the data frame of the lens data DLC, the lens microcomputer 111 adds a communication standby request BUSY frame when it is necessary to notify the camera microcomputer 205 of a communication standby request. The camera microcomputer 205 monitors the notification state of the communication standby request BUSY, and during the notification of the communication standby request BUSY, it is prohibited to assert the CTS signal that is the next communication request. 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 CTS signal as the next communication request on condition that the communication standby request BUSY is canceled and the transmission of the data frame of the camera data DCL is completed.

  Thus, after the communication start event from the camera microcomputer 205 becomes a trigger and the communication request CTS is asserted, the lens microcomputer 111 starts data frame transmission of the lens data DLC. The camera microcomputer 205 detects this and starts data frame transmission of the camera data DCL. When there is a communication standby request, a BUSY notification frame is added after the transmission of the lens data DLC data frame, and then the BUSY notification is negated, and a series of communication flows is completed. With this communication flow control, 1-byte communication data can be transmitted and received between the camera microcomputer 205 and the lens microcomputer 111.

  Next, the DLC 2ch communication system will be described with reference to FIG. FIG. 4 is an explanatory diagram of communication (second communication) using the DLC 2ch communication method. In the DLC2ch communication method, a lens data signal DLC2, which is a second DLC signal for transmitting data from the interchangeable lens 100 to the camera body 200, is used. In this communication method, large-capacity data transmission can be realized in a short time by using two lens data signals. FIG. 4 shows a communication signal waveform of one frame, which is the minimum communication unit, and a signal waveform in a case where three frames of this one-frame communication are communicated continuously. Hereinafter, the data format of the two-line lens data signals DLC and DLC2 and the communication flow control method in the DLC2ch communication method will be described.

  First, the data format of the data signal DLC includes only data frames for one frame, and there is no BUSY frame. Therefore, this data format is a format in which the communication wait request BUSY cannot be notified from the lens microcomputer 111 to the camera microcomputer 205. The purpose of use is for high-speed transfer of large-capacity data, but is specialized as a communication mode used only when transferring data from the lens microcomputer 111 to the camera microcomputer 205. For this reason, the data transfer direction (communication direction) is limited to only transfer from the lens microcomputer 111 to the camera microcomputer 205, and transfer from the camera microcomputer 205 to the lens microcomputer 111 cannot be performed. The definition between one frame and the next frame is a format in which continuous communication is possible with no gap between frames. The data frames of the two-line lens data signals DLC and DLC2 are defined in the same format. The purpose of this is to manage the number of frames transmitted by the data signal DLC and the data signal DLC2 to be the same even when a pause occurs during communication due to flow control. Aligned to the length. On the other hand, the relative relationship between the bit positions of the data frames does not necessarily need to be matched, and is allowed as long as the amount of deviation between the bit positions does not exceed one frame length.

  Such asynchronous serial communication (second communication) is realized using a communication request signal CTS and data signals DLC and DLC2 transmitted / received via three communication lines. That is, the communication request signal CTS (first signal) is transmitted from the camera microcomputer 205 to the lens microcomputer 111 via the first communication line. The data signal DLC (second signal) is transmitted from the lens microcomputer 111 to the camera microcomputer 205 via the second communication line. The data signal DLC2 (fourth signal) is transmitted from the lens microcomputer 111 to the camera microcomputer 205 via the third communication line.

  A switching circuit 151 for switching the signal direction (communication direction) is provided on the third communication line. For this reason, by switching the communication direction by the switching circuit 151, the communication of the second transmission data signal DLC2 from the lens microcomputer 111 is used instead of the transmission data signal DCL from the camera microcomputer 205 for the third communication line. Used as a line. As a result, high-speed data transfer of a large amount of data from the lens microcomputer 111 can be realized, and at the same time, communication flow control capable of notifying a communication pause request from each of the camera microcomputer 205 and the lens microcomputer 111 can be realized. Therefore, it is possible to perform an appropriate communication suspension notification according to the processing speed of the microcomputer, and it is possible to realize high-speed communication of a large amount of data making full use of the microcomputer processing performance.

  When switching from the normal communication method to the DLC2ch communication method, it is necessary to avoid collision of output signals in the lens communication interface circuit 112 and the camera communication interface circuit 208, respectively. Hereinafter, with reference to FIG. 5 to FIG. 7, a procedure for switching each communication interface circuit for preventing signal collision will be described.

  FIG. 6 is a block diagram of communication means for performing communication between the camera body 200 and the interchangeable lens 100, and corresponds to the detailed view of FIG. As shown in FIG. 6, the lens communication interface circuit 112 includes a camera I / F side level fixing circuit 152 (second voltage control circuit) and a lens microcomputer side level fixing circuit 153 (first voltage control circuit). Including a voltage control circuit. The camera I / F side level fixing circuit 152 is provided between the switching circuit 151 and the camera body 200. The lens microcomputer side level fixing circuit 153 is provided between the switching circuit 151 and the communication unit 111a.

  The camera I / F side level fixing circuit 152 sets the level (voltage) on the camera I / F side (camera communication interface circuit 208 side) of the lens communication interface circuit 112 to a high state or a low state (a predetermined voltage corresponding to each state). ) Or control to a floating state. The camera I / F side level fixing circuit 152 has, for example, a pull-up resistor. When fixing (controlling) the level (voltage) on the camera I / F side of the lens communication interface circuit 112 to the high state (predetermined voltage), connect the pull-up resistor to the power supply (pull the voltage on the camera I / F side). Up). Further, when the level on the camera I / F side is fixed to a low state, a pull-down resistor is connected to GND. In the floating state, nothing is connected. Further, the camera-lens communicates normally high, and normally the output of the camera microcomputer 205, the output of the camera communication interface circuit 208, and the output of the lens communication interface circuit 112 are all in a high state.

  Similarly to the camera I / F level fixing circuit 152, the lens microcomputer side level fixing circuit 153 has a pull-up resistor and a pull-down resistor, and the lens microcomputer side level (voltage) of the lens communication interface circuit 112 is fixed to a predetermined voltage. (Control. That is, the lens microcomputer side level fixing circuit 153 controls the voltage on the communication unit side of the switching circuit 151 to a predetermined first voltage, and the camera I / F side level fixing circuit 152 is a voltage on the imaging device side of the switching circuit. Is controlled to a predetermined second voltage. Each voltage control circuit of the present embodiment switches from the first communication (normal communication method) from the camera body 200 to the interchangeable lens 100 to the second communication (DLC 2ch communication method) from the interchangeable lens 100 to the camera body 200. In this case, the voltage of the switching circuit 151 is controlled to a predetermined voltage.

  As shown in FIG. 2, when the communication direction of the input / output buffer of the camera data signal DCL of the camera communication interface circuit 208 is switched to the camera direction, the camera data signal DCL of the lens communication interface circuit 112 is opposed to the input buffer. . Since these are in the input terminal state, the input level becomes undefined, and the output level of each buffer also becomes undefined. When the input level of the camera data signal DCL of the camera communication interface circuit 208 becomes low for some reason, the output level also becomes low, a through current flows between the camera microcomputer 205 and the camera communication interface circuit 208, and the element is turned on. There is a possibility of destruction.

  Here, with reference to FIG. 5 and FIG. 7, the communication control method at the time of switching from a normal communication system to a DLC2ch communication system is demonstrated. FIG. 5 is a timing chart of communication control when the communication method is switched from the normal communication method to the DLC 2ch communication method. FIG. 7 is a flowchart of communication control when the communication method is switched from the normal communication method to the DLC2ch communication method. Each step in FIG. 7 is mainly executed by the camera microcomputer 205 and the lens microcomputer 111.

  First, in steps S801 and S802, the camera microcomputer 205 and the lens microcomputer 111 communicate with each other using a normal communication method. Subsequently, in step S803, the camera microcomputer 205 transmits a DLC2ch switching command to the lens microcomputer. In steps S804 and S805, the lens microcomputer 111 fixes the camera I / F side level fixing circuit 152 to high in accordance with normally high communication. For example, it connects to a power supply via a pull-up resistor. Subsequently, in step S806, the lens microcomputer 111 notifies the camera microcomputer 205 of completion of switching preparation in the next frame using the DLC line. Thereafter, when the BUSY notification is negated in step S807, the camera microcomputer 205 recognizes that the lens microcomputer 111 is in a communicable state in steps S808 and S809.

  In step S810, the camera microcomputer 205 switches the input / output buffer of the camera data signal DCL switching circuit 218 of the camera communication interface circuit 208 in the camera direction. That is, the camera microcomputer 205 switches the communication buffer from the first buffer 218a to the second buffer 218b). In step S811, the camera microcomputer 205 switches the input / output buffer of the camera microcomputer 205 to input. In step S812, the camera microcomputer 205 notifies the lens microcomputer 111 that the switching has been completed by asserting the CTS signal after the buffer direction switching is completed. When the lens microcomputer 111 detects that the CTS signal is asserted in step S813, the lens microcomputer 111 connects the lens microcomputer side level fixing circuit 153 to high in step S814. Thereafter, in step S815, the input / output buffer direction (communication direction) of the switching circuit 151 of the camera data signal DCL of the lens communication interface circuit 112 is switched to the camera direction. In step S816, the camera I / F side level fixing circuit 152 is switched to a floating state (the control of the voltage of the switching circuit 151 is stopped by releasing the pull-up resistor on the camera I / F side).

  In step S817, the input / output buffer of the lens microcomputer 111 is switched to output. In step S818, the lens microcomputer side level fixing circuit 153 is put into a floating state (the control of the voltage of the switching circuit 151 is stopped by releasing the pull-up resistor on the lens microcomputer side). When the input / output buffer of the lens microcomputer 111 is switched to output, the lens microcomputer 111 is in a high output state. When the switching is completed, the lens microcomputer 111 notifies the camera microcomputer 205 that the switching is completed by transmitting a completion code to the lens data DLC in step S819. When the camera microcomputer 205 receives the completion of switching in step S802, the DLC2ch communication method is started by negating the CTS signal once and asserting the CTS signal again (S821 to S824). In this way, the camera microcomputer 205 and the lens microcomputer 111 confirm each other using the lens data DLC and CTS, and the input / output buffers of the DCL signal switching circuits 218 and 151 are switched, thereby preventing data collision. be able to.

  Next, referring to FIG. 8, a procedure for switching the communication direction by both communication interface circuits when switching from the DLC 2ch communication method to the normal communication method will be described. FIG. 8 is a timing chart of communication control when the communication method is switched from the DLC 2ch communication method to the normal communication method. Even when switching from the DLC2ch communication system to the normal communication system, it is necessary to avoid collision of output signals with each other. The operation of this embodiment is in the reverse order to that of the first embodiment. Hereinafter, this point will be described.

  The camera microcomputer 205 negates the CTS signal after completing reception of the data amount defined in advance by DLC2ch communication. Thereafter, by asserting the CTS signal, the lens microcomputer 111 is requested to switch from the DLC2ch communication method to the normal communication method. When the lens microcomputer 111 detects the assertion of the CTS signal, the lens microcomputer side level fixing circuit 153 (first voltage control circuit) is fixed to high (predetermined voltage), and the input / output buffer of the lens microcomputer 111 is switched to the input. . The lens microcomputer 111 fixes the camera I / F level fixing circuit 152 to high and switches the input / output buffer of the DCL signal switching circuit 151 in the input direction. That is, the lens microcomputer 111 switches the buffer of the switching circuit 151 from the second buffer 151b to the first buffer 151a in order to input a DCL signal from the camera microcomputer 205. Then, the lens microcomputer 111 puts the lens microcomputer side level fixing circuit 153 into a floating state.

  When the switching is completed, the lens microcomputer 111 notifies the camera microcomputer 205 that the switching is completed by transmitting a completion code to the lens data DLC. Upon receipt of the completion notification, the camera microcomputer 205 switches the input / output buffer of the camera microcomputer 205 to output, and then switches the DCL buffer direction (communication direction) of the camera communication interface circuit 208 to the lens direction. When the input / output buffer of the camera microcomputer 205 is switched to output, the output is high. The camera microcomputer 205 negates the CTS signal once to complete the switching from the DLC2ch communication method to the normal communication method. The lens microcomputer 111 receives the negation of the CTS signal, recognizes the completion of the switching of the communication system of the camera microcomputer 205, and switches the communication system on the lens side by floating the camera I / F level fixing circuit 152. Complete. As soon as the camera microcomputer 205 is ready, it asserts the CTS signal to start normal communication.

  Each voltage control circuit of the present embodiment switches from the second communication (DLC 2ch communication method) from the interchangeable lens 100 to the camera body 200 to the first communication (normal communication method) from the camera body 200 to the interchangeable lens 100. In this case, the voltage of the switching circuit 151 is controlled to a predetermined voltage. For this reason, even when switching from the DLC2ch communication system to the normal communication system, the camera microcomputer 205 and the lens microcomputer 111 check each other and switch the input / output buffers of the DCL signal switching circuit 151 to prevent data collision. be able to.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 9 is a block diagram of communication means (communication circuit) that performs communication between the camera body 200 and the interchangeable lens 100. The present embodiment relates to a configuration for preventing data collision when switching from the normal communication method to the DLC2ch communication method.

  As shown in FIG. 9, the communication means of this embodiment replaces the camera I / F side level fixing circuit 152 of Embodiment 1 described with reference to FIG. 6 with the lens I / F in the camera communication interface circuit 208. An F-side level fixing circuit 258 is included. The lens I / F side level fixing circuit 258 sets the level (voltage) on the lens I / F side (lens device side) of the camera communication interface circuit 208 (switching circuit 218) to a high state or a low state (predetermined corresponding to each state). Voltage) or a floating state. For example, when the level on the lens I / F side of the camera communication interface circuit 208 is fixed to high, a pull-up resistor is connected to the power source. When the level is fixed to low, a pull-down resistor is connected to GND. When the level is set to a floating state, nothing is connected. The lens I / F side level fixing circuit 258 has the same configuration as the camera I / F side level fixing circuit 152. The operation of the communication means of this embodiment will be described below.

  During communication using the normal communication method, a DLC2ch switching command is transmitted from the camera microcomputer 205 to the lens microcomputer 111. The lens microcomputer 111 notifies the camera microcomputer 205 of completion of switching preparation in the next frame using the DLC line. Thereafter, when the BUSY notification is negated, the camera microcomputer 205 recognizes that the lens microcomputer 111 is in a communicable state and starts a switching process. The camera microcomputer 205 fixes the lens I / F side level fixing circuit 258 to high in accordance with normally high communication.

  Subsequently, the input / output buffer of the camera data signal DCL switching circuit 218 of the camera communication interface circuit 208 is switched in the camera direction (second buffer 218b), and the input / output buffer of the camera microcomputer 205 is switched to input. After completing the switching of the buffer direction, the camera microcomputer 205 asserts the CTS signal to notify the lens microcomputer 111 that the switching has been completed. When the lens microcomputer 111 detects that the CTS signal is asserted, it connects the lens microcomputer side level fixing circuit 153 to high. Thereafter, the input / output buffer direction of the lens communication interface circuit 112 is switched to the camera direction. The input / output buffer of the lens microcomputer 111 is switched to the output, and the lens microcomputer side level fixing circuit 153 is brought into a floating state. When the input / output buffer of the lens microcomputer 111 is switched to output, the lens microcomputer 111 is in a high output state. When the switching is completed, the lens microcomputer 111 notifies the camera microcomputer 205 that the switching has been completed by transmitting a completion code to the lens data DLC. Upon receipt of the switching completion, the camera microcomputer 205 switches the lens I / F level fixing circuit 258 to the floating state, negates the CTS signal once, and asserts the CTS signal again, thereby starting the DLC2ch communication method.

  According to each embodiment, it is possible to provide a lens apparatus, an imaging apparatus, and a lens apparatus and a communication control method for the imaging apparatus that can reliably switch the data communication direction while avoiding data collision.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary.

  For example, in each embodiment, the lens microcomputer side level fixing circuit is provided, but instead of this, a circuit (second voltage control circuit) for fixing the camera microcomputer side level in the camera communication interface circuit is provided. The same effect can be obtained. That is, at least one level fixing circuit (at least one of the first voltage control circuit and the second voltage control circuit) may be provided in at least one of the lens communication interface circuit and the camera communication interface circuit. Further, although each level fixing circuit is described as being normally in a floating state, it may be partially in a pull-up state. Further, regarding the order of switching control in the level fixing circuit and the buffer direction, the order is arbitrary as long as the switching control is performed so that the input level is always determined.

100 Interchangeable lens (lens device)
111a communication unit 151 switching circuit 152 camera I / F side level fixing circuit (voltage control circuit)
153 Lens microcomputer side level fixing circuit (voltage control circuit)

Claims (13)

A lens device detachable from an imaging device,
A communication unit capable of bidirectional communication with the imaging device;
A switching circuit for switching the communication direction;
And a voltage control circuit configured to control a voltage of the switching circuit to a predetermined voltage when the communication direction is switched. The voltage control circuit has a pull-up resistor,
The lens apparatus according to claim 1, wherein the voltage is fixed to the predetermined voltage by pulling up the voltage of the switching circuit. The switching circuit is
A first buffer and a second buffer provided in parallel;
The lens apparatus according to claim 1, wherein the first buffer or the second buffer is exclusively selected according to the communication direction.   The voltage control circuit is provided between the switching circuit and the communication unit, and controls the voltage on the communication unit side of the switching circuit to the predetermined voltage. The lens device according to any one of the above. The voltage control circuit includes:
A first voltage control circuit provided between the switching circuit and the communication unit;
A second voltage control circuit provided between the switching circuit and the imaging device,
The first voltage control circuit controls the voltage on the communication unit side of the switching circuit to a predetermined first voltage,
4. The lens device according to claim 1, wherein the second voltage control circuit controls the voltage on the imaging device side of the switching circuit to a predetermined second voltage. 5.   When the voltage control circuit switches from the first communication from the imaging device to the lens device to the second communication from the lens device to the imaging device, the voltage of the switching circuit is changed to the predetermined voltage. The lens device according to claim 1, wherein the lens device is controlled.   When the voltage control circuit switches from the second communication from the lens device to the imaging device to the first communication from the imaging device to the lens device, the voltage of the switching circuit is changed to the predetermined voltage. The lens device according to claim 1, wherein the lens device is controlled. The communication unit is
Receiving a first signal from the imaging device via a first communication line;
A second signal is transmitted to the imaging device via a second communication line;
In the first communication, a third signal is received from the imaging device via a third communication line,
In the second communication, a fourth signal is transmitted to the imaging device via the third communication line,
The lens device according to claim 1, wherein the switching circuit is provided on the third communication line. An imaging device in which a lens device is detachable,
A communication unit capable of bidirectional communication with the lens device;
A switching circuit for switching the communication direction;
An image pickup apparatus comprising: a voltage control circuit that controls a voltage of the switching circuit to a predetermined voltage when the communication direction is switched.   The voltage control circuit is provided between the switching circuit and the lens device, and controls the voltage on the lens device side of the switching circuit to the predetermined voltage. Imaging device. The voltage control circuit includes:
A first voltage control circuit provided between the switching circuit and the lens device;
A second voltage control circuit provided between the switching circuit and the communication unit,
The first voltage control circuit controls the voltage on the lens device side of the switching circuit to a predetermined first voltage,
The imaging apparatus according to claim 9, wherein the second voltage control circuit controls a voltage on a communication unit side of the switching circuit to a predetermined second voltage. A communication control method for a lens device detachable from an imaging device,
Receiving a signal related to switching of a communication method;
Controlling the voltage of the switching circuit including the first buffer and the second buffer for switching the communication direction to a predetermined voltage;
Switching the buffer of the switching circuit used for communication from the first buffer to the second buffer in a state where the voltage of the switching circuit is controlled to the predetermined voltage;
And a step of stopping the control of the voltage of the switching circuit. A communication control method for an imaging apparatus in which a lens apparatus is removable,
Transmitting a signal related to switching of a communication method;
Controlling the voltage of the switching circuit including the first buffer and the second buffer for switching the communication direction to a predetermined voltage;
Switching the buffer of the switching circuit used for communication from the first buffer to the second buffer in a state where the voltage of the switching circuit is controlled to the predetermined voltage;
And a step of stopping control of the voltage of the switching circuit.