JP7119148B2 - ACCESSORY DEVICE, IMAGING DEVICE, CONTROL METHOD AND STORAGE MEDIUM - Google Patents

Description

The present invention relates to an imaging device (hereinafter referred to as a camera body) and an accessory device such as an interchangeable lens that can communicate with each other.

In an interchangeable-accessory camera system that includes a camera body in which an accessory device is attachable and detachable, communication is performed for the camera body to control the accessory device and for the accessory device to provide the camera body with data necessary for its control and imaging. will be In particular, when an interchangeable lens is used to capture a video for recording or a video for live view display, smooth lens control that matches the imaging cycle is required. need to be synchronized. Therefore, the camera body needs to complete the reception of data from the interchangeable lens and the transmission of various commands and requests to the interchangeable lens within the imaging cycle. However, as the amount of data received by the camera body from the interchangeable lens increases and the imaging cycle is shortened (higher frame rate), communication of a large amount of data in a shorter time is required.

Patent Document 1 discloses a camera system having a one-way communication mode (hereinafter also referred to as high-speed mode) and a two-way communication mode (hereinafter also referred to as low-speed mode). In high-speed mode, full-duplex communication is performed by using a unidirectional communication channel for data communication from the camera body to the interchangeable lens and another unidirectional communication channel for data communication from the interchangeable lens to the camera body in parallel. Burst communication is used to transfer large amounts of data. On the other hand, in the low-speed mode, request communication from one of the camera body and the interchangeable lens to the other and data communication from the other to the other in response to the request are performed on one communication channel while switching the communication direction.

JP 2010-237514 A

In the camera system disclosed in Patent Document 1, when continuous data communication becomes difficult due to insufficient processing speed of the interchangeable lens or the microcomputer mounted on the camera body in the high-speed mode, the data communication is performed. cannot be stopped temporarily. As a result, there is a risk that data communication will fail. In order to avoid the collapse of data communication, it is necessary to either establish a low data communication speed as a communication standard with sufficient margin for the performance of various microcomputers assumed, or reduce the amount of data to be communicated. be. However, even if both the camera body and the interchangeable lens are equipped with microcomputers having high processing performance, the processing performance cannot be utilized, and high-speed data communication cannot be realized.

Also, for example, if the capacity of a buffer provided in the camera body for storing data transmitted from the interchangeable lens is small for a large amount of data transmitted from the interchangeable lens to the camera body at once by burst communication, the data may be stored. It may not fit in the buffer.

The present invention provides an accessory device, an imaging device, and the like that enable smooth and high-speed communication of a large amount of data.

An accessory device as one aspect of the present invention is an accessory device detachably attached to an imaging device, and has accessory control means for controlling communication between the accessory device and the imaging device. The accessory control means, in the first mode, changes the signal level of the first channel to the second signal level after the signal level of the first channel changes from the first signal level to the second signal level. responsive to maintaining communication with the imaging device via the second channel and the third channel , the accessory control means controlling the signal level of the first channel to decrease from the second signal level to the first channel; The transmission of accessory data is stopped in response to a change in the signal level of .

Further, an imaging device as another aspect of the present invention is an imaging device to which an accessory device is detachably mounted, and has camera control means for controlling communication between the imaging device and the accessory device. In the first mode, the camera control means causes the signal level of the first channel to change to the second signal level after the signal level of the first channel changes from the first signal level to the second signal level. responsive to maintaining communication with the accessory device via the second channel and the third channel , the camera control means controlling the signal level of the first channel to decrease from the second signal level to the first channel; and stop receiving the accessory data in response to a change in the signal level of the

A control method as another aspect of the present invention is a control method for controlling communication between an accessory device detachably attached to an imaging device and an imaging device, the first mode, wherein the signal level of the first channel is maintained at the second signal level after the signal level of the first channel changes from the first signal level to the second signal level. , communicating with the imaging device via the second channel and the third channel ; and in response to the signal level of the first channel changing from the second signal level to the first signal level, and stopping transmission of accessory data .

Further, a control method as another aspect of the present invention is a control method for controlling communication between an imaging device and an accessory device, in an imaging device to which the accessory device is detachably attached, comprising : mode, in response to maintaining the signal level of the first channel at the second signal level after the signal level of the first channel changes from the first signal level to the second signal level, communicating with the accessory device over a second channel and a third channel ; and c. stopping receiving data .

A computer-readable storage medium that stores a program that causes a computer to execute each of the control methods described above also constitutes another aspect of the present invention.

According to the present invention, since each of the accessory device and the imaging device can stop or terminate data transmission from the other, a large amount of data can be communicated smoothly and at high speed between the accessory device and the imaging device. can.

1 is a block diagram showing the configuration of a camera system that is Embodiment 1 of the present invention. FIG. 4 is a block diagram showing a communication circuit in the first communication setting according to the first embodiment; FIG. 4 is a block diagram showing the configuration of the camera and lens data transmitting/receiving unit in the first communication setting according to the first embodiment; FIG. 4 is a block diagram showing the configuration of the communication unit in the first communication setting according to the first embodiment; FIG. 4A and 4B are diagrams showing waveforms of signals exchanged between the camera body and the interchangeable lens in the first communication setting in the first embodiment; FIG. 4A and 4B are diagrams showing waveforms of signals exchanged between the camera body and the interchangeable lens in the non-BUSY addition mode among the first communication settings in the first embodiment; FIG. 4 is a block diagram showing a communication circuit in a second communication setting according to the first embodiment; FIG. 6 is a block diagram showing the configuration of the camera and lens data transmitting/receiving section in the second communication setting according to the first embodiment; FIG. 4A and 4B are diagrams showing waveforms of signals exchanged between the camera body and the interchangeable lens in the second communication setting in the first embodiment; FIG. 4A and 4B are diagrams showing the relationship of data frames exchanged between the camera body and the interchangeable lens in the first communication setting according to the first embodiment; FIG. FIG. 2 is a block diagram showing the configuration of a camera system that is Embodiment 2 of the present invention. 9 is a flowchart showing communication control in the second embodiment; FIG. 9 is a diagram showing waveforms of signals exchanged between the camera body and the interchangeable lens in Example 2; FIG. 11 is a diagram showing a setting example of a predetermined time in a camera system that is Embodiment 3 of the present invention; 4 is a flow chart showing communication control in Embodiment 4 of the present invention. FIG. 11 is a block diagram showing the configuration of a memory controller in Example 4; FIG. 11 is a diagram showing waveforms of signals exchanged between a camera body and an interchangeable lens in Example 4;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an imaging system (hereinafter referred to as a camera system) including a camera body 200 as an imaging device according to the first embodiment of the present invention and an interchangeable lens 100 as an accessory device detachably attached thereto. is shown.

The camera body 200 and the interchangeable lens 100 transmit control commands and internal information via respective communication units, which will be described later. Both communication units support multiple communication formats, and by synchronizing with each other and switching to the same communication format according to the type of data to be communicated and the communication purpose, the optimum communication format can be selected for various situations. It is possible to

First, specific configurations of the interchangeable lens 100 and the camera body 200 will be described. Interchangeable lens 100 and camera body 200 are mechanically and electrically connected via mount 300, which 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 operates various actuators and a lens microcomputer (hereinafter referred to as a lens microcomputer) 111, which will be described later. Let Also, the interchangeable lens 100 and the camera body 200 communicate with each other via a communication terminal section (shown in FIG. 2) provided on the mount 300 .

The interchangeable lens 100 has an imaging optical system. The imaging optical system includes, in order from the object OBJ side, a field lens 101, a variable power lens 102 that performs variable magnification, 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 magnification lens 102 and focus lens 104 are held by lens holding frames 105 and 106, respectively. The lens holding frames 105 and 106 are guided by guide shafts (not shown) so as to be movable in the optical axis direction indicated by broken lines in the drawing, and are driven by stepping motors 107 and 108 in the optical axis direction, respectively. Stepping motors 107 and 108 respectively move the variable magnification lens 102 and the focus lens 104 in synchronization with the drive pulse.

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

A lens microcomputer 111 is an accessory control section that controls the operation of each section in the interchangeable lens 100 . The lens microcomputer 111 receives a control command transmitted from the camera body 200 via a lens communication section 112 (lens data transmission/reception section 112b) as an accessory communication section, and receives a transmission request for lens data (accessory data). Also, the lens microcomputer 111 performs lens control corresponding to the control command, and transmits lens data corresponding to the transmission request to the camera body 200 via the lens communication unit 112 . The lens microcomputer 111 performs operations related to communication with the camera body 200 (camera microcomputer 205 described later) according to a communication control program as a computer program.

In this embodiment, as a communication method between the lens microcomputer 111 and the camera microcomputer (hereinafter referred to as camera microcomputer) 205, asynchronous communication is adopted. The lens microcomputer 111 and the camera microcomputer 205 can share error information indicating that a communication abnormality (communication error) has occurred.

Further, 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 zooming and focusing among the control commands to drive the stepping motors 107 and 108 . As a result, zoom processing for controlling the zooming operation by the variable-magnification lens 102 and AF (autofocus) processing for controlling the focus adjustment operation by the focus lens 104 are performed.

The interchangeable lens 100 has a manual focus ring 130 that can be rotated by the user, and a focus encoder 131 that detects the amount of rotational operation of the manual focus ring 130 . The lens microcomputer 111 causes the focus drive circuit 120 to drive the stepping motor 108 according to the amount of rotation of the manual focus ring 130 detected by the focus encoder 131 to move the focus lens 104 . Thereby, MF (manual focus) is performed.

The diaphragm unit 114 includes diaphragm blades 114a and 114b. The states of the aperture 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 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 amount adjustment operation by the diaphragm unit 114 is controlled.

Furthermore, the lens microcomputer 111 drives an anti-vibration actuator 126 via an anti-vibration driving circuit 125 according to the shake detected by an unillustrated shake sensor such as a vibration gyroscope provided in the interchangeable lens 100 . As a result, vibration reduction processing for controlling the movement of the image blur correction lens 103 is performed.

The camera body 200 includes an imaging element 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 a camera microcomputer) 205, and a display. 206.

The imaging element 201 photoelectrically converts a subject image formed by the imaging optical system in the interchangeable lens 100 and outputs an electric signal (analog signal). An 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, from the video signal, the contrast state of the subject image, that is, the focus information indicating the focus state of the imaging optical system and the luminance information indicating the exposure state. 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 composition, focus state, and the like. The signal processing circuit 203 also outputs the video signal to the recording unit 204, and the recording unit 204 records the video signal.

A memory (storage unit) 210 is configured by a DDR (Double Data Rate SDRAM) or the like. The memory 210 stores a digital image signal obtained by the image sensor 201 or a video signal generated by the image processing circuit 203, and stores lens data received from the lens microcomputer 111. FIG.

A camera microcomputer 205 as a camera control unit controls the camera body 200 according to inputs from a camera operation unit 207 including an imaging instruction switch and various setting switches (not shown). Also, the camera microcomputer 205 transmits a control command related to the zooming operation of the zoom lens 102 to the lens microcomputer 111 via the camera communication unit 208 (camera data transmission/reception unit 208b) in accordance with the operation of a zoom switch (not shown). Furthermore, the camera microcomputer 205 transmits to the lens microcomputer 111 via the camera communication unit 208 control commands related to the light amount adjustment operation of the aperture unit 114 according to the luminance information and the focus adjustment operation of the focus lens 104 according to the focus information. . The camera microcomputer 205 performs operations related to communication with the lens microcomputer 111 according to a communication control program as a computer program.

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

The camera microcomputer 205 has a camera communication interface circuit 208a, and the lens microcomputer 111 has a lens communication interface circuit 112a. The camera microcomputer 205 (camera data transmitting/receiving unit 208b) and the lens microcomputer 111 (lens data transmitting/receiving unit 112b) are connected to a communication terminal unit (indicated by three rectangles in the drawing) provided on the mount 300 and the communication interface circuits 208a and 112a. Communicate via In this embodiment, the camera microcomputer 205 and the lens microcomputer 111 perform (three-wire) asynchronous serial communication using three channels. The camera data transmission/reception unit 208b and the camera communication interface circuit 208a constitute the camera communication unit 112, and the lens data transmission/reception unit 112b and the lens communication interface circuit 112a constitute the lens communication unit 112 as an accessory communication unit.

The three channels are composed of a transmission request channel as a notification channel, a first data communication channel, and a second data communication channel. The transmission request channel is used for notification of a lens data transmission request (transmission instruction) from the camera microcomputer 205 to the lens microcomputer 111, a communication setting switching request (switching instruction), etc., which will be described later. The notification on the transmission request channel is performed by switching the signal level (voltage level) on the transmission request channel between High (first level) and Low (second level). In the following description, the signal supplied to the request-to-send channel is referred to as a request-to-send signal RTS.

A first data communication channel is used for lens data transmission from the lens microcomputer 111 to the camera microcomputer 205 . In the following description, lens data (accessory 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. A second data communication channel is used for camera data transmission from the camera microcomputer 205 to the lens microcomputer 111 . In the following description, 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.

A transmission request signal RTS is sent from the camera microcomputer 205 as a communication master to the lens microcomputer 111 as a communication slave. The camera data signal DCL includes control commands, transmission request commands, and the like from the camera microcomputer 205 to the lens microcomputer 111 . The lens data signal DLC includes various data transmitted from the lens microcomputer 111 to the camera microcomputer 205 . The camera microcomputer 205 and the lens microcomputer 111 set the communication speed in advance, and perform transmission/reception at the communication bit rate according to this setting. The communication bit rate indicates the amount of data that can be transferred in one second, and is expressed in units of bps (bits per second). The camera microcomputer 205 and the lens microcomputer 111 communicate with each other by a full-duplex communication method (full-duplex method).

Instead of asynchronous serial communication using three channels, clock synchronous serial communication using three channels may be performed. Further, when the amount of data transmitted from the lens microcomputer 111 to the camera microcomputer 205 is large, the clock synchronous serial communication may be switched to the asynchronous serial communication. In this case, the notification channel can be used as a clock line for supplying the clock signal LCLK from the camera microcomputer 205 to the lens microcomputer 111 . As a result, two communication methods, asynchronous serial communication and clock synchronous serial communication, can be used by switching without adding a new channel.

In clock-synchronous serial communication using three channels, a clock signal LCLK is output from the camera microcomputer 205 as a communication master to the lens microcomputer 111 as a communication slave through the clock channels. The camera data signal DCL includes control commands, transmission request commands, and the like from the camera microcomputer 205 to the lens microcomputer 111 . 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. In the clock-synchronous serial communication, the camera microcomputer 205 and the lens microcomputer 111 communicate with each other in a full-duplex communication system in which transmission and reception are performed in synchronization with a common clock signal LCLK.

Next, the first communication setting, which is the communication setting between the camera microcomputer 205 and the lens microcomputer 111, will be described with reference to FIGS. 3 to 5 and 9. FIG. 3 shows the configuration of the camera data transmission/reception unit 208b in the camera microcomputer 205 and the lens data transmission/reception unit 112b in the lens microcomputer 111. As shown in FIG. 205a is a CPU as a main body of the camera microcomputer 205; Reference numeral 301 denotes an RTS control unit, and 302 denotes a transmission data buffer (camera data buffer) composed of a RAM or the like. Reference numeral 303 denotes a reception data buffer composed of a RAM or the like, and 304 denotes a buffer control unit for controlling data storage and data reading in the buffers 302 and 303 .

3 shows the configuration of the camera data transmission/reception 208b in the camera microcomputer 205 in the camera body 200. As shown in FIG. 205a is a CPU as a main body of the camera microcomputer 205; 301 is an RTS control unit, and 302 is a transmission data buffer constituted by a RAM or the like. Reference numeral 303 denotes a reception data buffer composed of a RAM or the like, and 304 denotes a buffer control unit for controlling data storage and data reading in the buffers 302 and 303 .

On the other hand, in the lens microcomputer 111, 111a is a CPU as a main body of the lens microcomputer 111. FIG. Reference numeral 316 denotes an RTS detection unit, and 311 denotes a reception data buffer composed of a RAM or the like. Reference numeral 312 denotes a transmission data buffer (accessory data buffer) composed of a RAM or the like;

A camera data signal DCL transmitted from the camera microcomputer 205 to the lens microcomputer 111 is stored in the transmission data buffer 302 . For example, when transmitting a 128-byte camera data signal DCL, the 128-byte camera data signal DCL is stored in the transmission data buffer 302 before transmission is started. The buffer control unit 304 reads the camera data signal DCL transmitted from the transmission data buffer 302 for each frame. Then, the read camera data signal DCL for each frame is converted from a parallel data signal to a serial data signal by the parallel-serial conversion unit 305, and transmitted to the lens microcomputer 111 through the second data communication channel.

A camera data signal DCL transmitted from the camera microcomputer 205 is converted from a serial data signal to a parallel data signal by a serial-parallel converter 314 in the lens microcomputer 111 . The buffer control unit 313 stores the camera data signal DCL converted into the parallel data signal in the received data buffer 311 .

A lens data signal DLC transmitted from the lens microcomputer 111 to the camera microcomputer 205 is stored in the transmission data buffer 312 . For example, when transmitting a 128-byte lens data signal DLC, the transmission is started after the 128-byte lens data signal DLC is stored in the transmission data buffer 312 . The buffer control unit 313 reads the lens data signal DLC transmitted from the transmission data buffer 312 for each frame. Then, the read lens data signal DLC for each frame is converted from a parallel data signal to a serial data signal by the parallel-serial conversion unit 315 and transmitted to the camera microcomputer 205 through the first data communication channel.

The lens data signal DLC transmitted from the lens microcomputer 111 is converted from a serial data signal to a parallel data signal by the serial-parallel converter 306 in the camera microcomputer 205 . The buffer control unit 304 stores the lens data signal DLC converted into the parallel data signal in the received data buffer 303 . The lens data signal DLC stored in the reception data buffer 303 is read from the reception data buffer 303 by the DMA control unit 307, and the read data is transferred to the memory 210 and stored.

As further described below, this first communication setting includes a communication setting to which a BUSY frame is added (hereinafter referred to as a BUSY addition mode) and a communication setting to which a BUSY frame is not added (hereinafter referred to as a non-BUSY addition mode). and are provided. 4A to 4C show waveforms of signals exchanged between the camera microcomputer 205 and the lens microcomputer 111 in the first communication setting. A set of procedures for this exchange is called a communication protocol.

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

First, the data format of the lens data signal DLC will be described. One frame of the lens data signal DLC is composed of a data frame in the first half followed by a BUSY frame as a large division. The signal level of the lens data signal DLC is maintained at High in a non-transmission state in which data transmission is not performed.

The lens microcomputer 111 sets the signal 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 indicating the start of one frame. That is, a data frame starts from this start bit ST. The start bit ST is provided at the head bit of each frame of the lens data signal DLC.

Subsequently, the lens microcomputer 111 transmits 1-byte lens data in the next 8-bit period from the 2nd bit to the 9th bit. The data bit array is in the MSB first format, starting with the most significant data D7, followed by data D6 and 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 signal level of the lens data signal DLC to High during the period of the stop bit SP indicating the end of one frame. This ends the data frame period started from the start bit ST.

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

On the other hand, there are cases where it is unnecessary to notify the communication standby request BUSY from the lens microcomputer 111 to the camera microcomputer 205 . For this case, as indicated by "DLC (without BUSY)" in the figure, there is also provided a data format that configures one frame without adding a BUSY frame (hereinafter also referred to as BUSY notification). That is, as the data format of the lens data signal DLC, it is possible to select one with or without the addition of the BUSY notification according to the processing status on the lens microcomputer side.

A method of identifying whether or not there is a BUSY notification performed by the camera microcomputer 205 will be described. The signal waveform indicated by "DLC (without BUSY)" in FIG. 4A and the signal waveform indicated by "DLC (with BUSY)" in FIG. 4A include bit positions B1 and B2. there is The camera microcomputer 205 selects one of these bit positions B1 and B2 as the BUSY identification position P for identifying the presence/absence of BUSY notification. Thus, in this embodiment, a data format is adopted in which the BUSY identification position P is selected from the bit positions of B1 and B2. As a result, it is possible to solve the problem that the processing time from the transmission of the data frame of the lens data signal DLC to the determination of the BUSY notification (DLC Low) differs depending on the processing performance of the lens microcomputer 111 .
Whether the BUSY identification position P is 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 communication. It is not necessary to fix the BUSY identification position P to either of the bit positions of B1 and B2, and it may be changed according to the processing capabilities of both microcomputers 205 and 111. FIG.

FIG. 4B shows signal waveforms in the case of continuous communication in the BUSY addition mode indicated by "DLC (with BUSY)" in FIG. 4A. A communication standby request BUSY (BUSY frame) from the lens microcomputer 111 is notified using the lens data signal DLC on the first data communication channel, and the next communication is started after the communication standby request BUSY is cancelled. CMD1 shown in FIG. 4B indicates a transmission request command transmitted from the camera microcomputer 205 to the lens microcomputer 111 as the camera data signal DCL. Upon receiving the transmission request command CMD1, the lens microcomputer 111 transmits to the camera microcomputer 205 a 2-byte lens data signal DT1 (DT1a, DT1b) corresponding to the transmission request command CMD1.

FIG. 4C shows signal waveforms when communication is performed by switching between the BUSY addition mode and the non-BUSY addition mode. In the example of FIG. 4C, communication is first performed in the BUSY addition mode, and then communication is performed in the non-BUSY addition mode. CMD2 indicates a control command and a transmission request command transmitted from the camera microcomputer 205 to the lens microcomputer 111 as the camera data signal DCL. Although the figure shows a case where the control command and the transmission request command are transmitted in one frame, the control command and the transmission request command may be transmitted in separate frames. The lens microcomputer 111 switches the communication setting (communication mode) from the BUSY addition mode to a method in which the BUSY frame is not added in response to receiving the control command of the command CMD2. Upon receiving the transmission request command of the command CMD2, the lens microcomputer 111 transmits to the camera microcomputer 205 a 3-byte lens data signal DT2 (DT2a to DT2c) corresponding to the transmission request command.

Next, the data format of the camera data signal DCL will be described. The specification of one data frame 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 under the first communication setting between the camera microcomputer 205 and the lens microcomputer 111 will be described. First, the communication procedure in the BUSY addition mode will be described.

When an event for starting communication with the lens microcomputer 111 occurs, the camera microcomputer 205 sets the level of the transmission request signal RTS to Low (hereinafter referred to as asserting the transmission request signal RTS). Notify transmission request. When the lens microcomputer 111 detects a transmission request due to the low transmission request signal RTS, the lens microcomputer 111 generates a lens data signal DLC to be transmitted to the camera microcomputer 205 . Then, when the preparation for transmission of the lens data signal DLC is completed, transmission of one frame of the lens data signal DLC through the first data communication channel is started. Here, the lens microcomputer 111 may start transmitting the lens data signal DLC within a set time mutually set between the camera microcomputer 205 and the lens microcomputer 111 after the transmission request signal RTS becomes Low. That is, it is necessary to determine the lens data to be transmitted by the time the first clock pulse is input between the time when the transmission request signal RTS becomes Low and the time when the transmission of the lens data signal DLC is started. No restrictions.

Next, the camera microcomputer 205 returns the level of the transmission request signal RTS to High in response to detection of the start bit ST, which is the first bit of the data frame of the lens data signal DLC received from the lens microcomputer 111 (hereinafter referred to as the transmission request signal negating the RTS). This cancels the transmission request and starts transmission of the camera data signal DCL through the second data communication channel. It does not matter which of the negation of the transmission request signal RTS and the start of transmission of the camera data signal DCL comes first.

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 the communication standby request BUSY. The camera microcomputer 205 monitors whether or not the communication standby request BUSY is notified, 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 performs necessary processing while waiting for communication from the camera microcomputer 205 by the communication standby request BUSY, and cancels the communication standby request BUSY after the next communication is ready. 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, in response to assertion of the transmission request signal RTS triggered by a communication start event in the camera microcomputer 205, the lens microcomputer 111 transmits the data frame of the lens data signal DLC to the camera microcomputer 205. to 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, the lens microcomputer 111 adds a BUSY frame after the data frame of the lens data signal DLC for the communication standby request BUSY as necessary, and then cancels the communication standby request BUSY, thereby completing the communication processing for one frame. complete. Through this communication processing, 1-byte data is exchanged between the camera microcomputer 205 and the lens microcomputer 111 .

Next, a communication procedure in the non-BUSY addition mode will be described. Compared to the BUSY addition mode, the non-BUSY addition mode enables faster data communication because the BUSY frame is not added.

FIG. 5A shows waveforms of signals exchanged between the camera microcomputer 205 and the lens microcomputer 111 in the non-BUSY addition mode. FIG. 5A shows signal waveforms when one frame, which is the minimum communication unit, is continuously communicated for three frames. As described above, in the non-BUSY addition mode, the communication standby request BUSY is not added to the lens data signal DLC.

In the non-BUSY addition mode, the data format of the lens data signal DLC is such that one frame consists of data frames only, and there is no BUSY frame. Therefore, in the non-BUSY addition mode, the lens microcomputer 111 cannot notify the camera microcomputer 205 of the communication standby request BUSY. Such a data format is used for continuous communication (burst communication) with short intervals between frames when transferring a relatively large amount of data between the camera microcomputer 205 and the lens microcomputer 111 . That is, the non-BUSY addition mode enables high-speed communication of large amounts of data.

In the non-busy addition mode, the number of stop bits SP, which are the last bit of each frame of the lens data signal DLC, is 2, which is larger than the number of stop bits ST of each frame of the camera data signal DCL. Due to this difference in the number of stop bits, the bit length of one frame of the lens data signal DLC is made longer than the bit length of one frame of the camera data signal DCL. This purpose will be explained later.

FIG. 5B shows signal waveforms when the camera microcomputer 205 and the lens microcomputer 111 respectively continuously transmit and receive the camera data signal DCL and the lens data signal DLC of n frames (that is, when performing burst communication). showing. Prior to the start of this communication, the camera microcomputer 205 transmits n I'm getting frame notifications.

When an event for starting communication with the lens microcomputer 111 occurs, the camera microcomputer 205 asserts the transmission request signal RTS. After that, in the non-BUSY addition mode, unlike the BUSY addition mode, the camera microcomputer 205 does not need to negate the transmission request signal RTS for each frame. remains asserted.

When the lens microcomputer 111 detects a transmission request by asserting the transmission request signal RTS, the lens microcomputer 111 generates a lens data signal DLC to be transmitted to the camera microcomputer 205 . Then, when preparation for transmission of the lens data signal DLC is completed, transmission of the first frame DL1 of the lens data signal DLC through the first data communication channel is started.

The lens microcomputer 111 that has transmitted the data frame of the lens data signal DLC of the first frame checks the transmission request signal RTS again. At this time, if the transmission request signal RTS is in an asserted state, the lens microcomputer 111 transmits the second frame DL2 of the next lens data signal DLC to the camera microcomputer 205 following the transmission of the completed first frame. As described above, the lens data signals DLC (DL1 to DLn) from the lens microcomputer 111 are continuously transmitted to the camera microcomputer 205 while the asserted state of the transmission request signal RTS is maintained. Then, when transmission of the number of frames n indicated in the data size information is completed, transmission of the lens data signal DLC is stopped.

From the camera microcomputer 205, in response to detection of the start bit ST for each frame of the lens data signal DCL from the lens microcomputer 111, n frames of the camera data signal DCL (DC1 to DCn) are transmitted through the second data communication channel. is sent. In this manner, the camera microcomputer 205 maintains the asserted state of the transmission request signal RTS, whereby continuous transmission/reception of the lens data signal DLC and the camera data signal DCL of the number of frames corresponding to the data size information can be performed.

The camera microcomputer 205 temporarily stores the lens data signal DLC continuously received from the lens microcomputer 111 in the received data buffer 303 via the serial-parallel converter 306 . The DMA control unit 307 transfers the lens data signal DLC stored in the reception data buffer 303 to the memory 210 and finally stores it in the memory 210 . Therefore, when receiving the lens data signal DLC having a data amount exceeding the capacity of the reception data buffer 303, the lens data signal DLC previously stored in the reception data buffer 303 is transferred to the memory 210, and then transferred to the buffer. 303 must be reserved.

However, if the DMA control unit 307 cannot access the memory 210 due to the processing status of the signal processing circuit 203 provided in the camera body 200, the lens data signal DLC continuously received from the lens microcomputer 111 can be transferred to the memory 210. become unable. As a result, it becomes impossible to secure a free space in the reception data buffer 303 and to store part of the continuously received lens data signals DLC in the memory 210 . For example, the lens data signal DLC that has already been received by the camera microcomputer 205 is overwritten by the data that is received later and that remains in the received data buffer 303 without being transferred to the memory 210 . Some data will not be stored. Therefore, it is necessary to temporarily stop communication between the camera microcomputer 205 and the lens microcomputer 111 before the data stored in the reception data buffer 303 is overwritten.

FIG. 5(C) shows the waveform of the signal when the camera microcomputer 205 or the lens microcomputer 111 instructs to temporarily stop communication during the continuous data transmission/reception communication shown in FIG. 5(B). . Here too, the lens microcomputer 111 starts transmitting the lens data signal DLC when the transmission request signal RTS is asserted from the camera microcomputer 205, and the camera microcomputer 205 transmits the camera data signal DCL in response to detection of the start bit ST. to start.

T2w1 indicates a communication stop period during which the camera microcomputer 205 instructs to stop communication. The instruction is notified to the lens microcomputer 111 by the camera microcomputer 205 temporarily negating the transmission request signal RTS. When the lens microcomputer 111 detects that the transmission request signal RTS has been negated, the lens microcomputer 111 completes transmission of the frame of the lens data signal DLC (DL6 in the figure, hereinafter referred to as a stop frame) that was being transmitted at the time of detection, and then transmits the frame. to stop. In response to the stop of transmission of the lens data signal DLC, the camera microcomputer 205 also stops transmission of the camera data signal DCL after transmitting the frame (DC6) corresponding to the stop frame of the camera data signal DCL. Through such communication control, even when a communication stop instruction is issued during continuous data transmission/reception communication, management is performed so that the number of transmitted frames of the lens data signal DLC and the camera data signal DCL are the same (synchronized). can be done.

The camera microcomputer 205 can instruct the lens microcomputer 111 to resume communication by re-asserting the transmission request signal RTS when the communication stop request event disappears. In response to the communication restart instruction, the lens microcomputer 111 restarts transmission of the lens data signal DLC from a frame (DL7: hereinafter referred to as restart frame) following the stop frame. Then, in response to detection of the restart frame start bit ST, the camera microcomputer 205 restarts transmission of the camera data signal DCL from the frame (DC7) corresponding to the restart frame.

Thus, the camera microcomputer 205 stops communication with the lens microcomputer 111 by temporarily negating the transmission request signal RTS. If the number of frames of the lens data signal DLC received at that time is less than the number of frames indicated in the data size information, the transmission request signal RTS is asserted again so that the lens data signal DLC from the lens microcomputer 111 can be received. can resume receiving

After the end of the communication stop period T2w1, neither the camera microcomputer 205 nor the lens microcomputer 111 instructs or notifies the communication stop, and continuous data communication is performed in the order of the restart frames DL7 and DC7 and the following frames DL8, DC8 to DL9 and DC9. I do.

When the transmission of the frame DL9 is completed in the lens microcomputer 111 (the reception of the frame DC9 by the camera microcomputer 205), a communication stop request event is generated. Notice. This notification is made by the lens microcomputer 111 not transmitting the lens data signal DLC even if the transmission request signal RTS is in an asserted state. T2w2 represents a communication stop period during which the lens microcomputer 111 notifies the communication stop.

The camera microcomputer 205 constantly monitors the start bit ST for each frame of the lens data signal DLC, and determines to stop transmission of the next frame of the camera data signal DCL when the start bit ST is not detected. For this reason, the camera microcomputer 205 transmits the camera data signal DCL (DC10) to the lens microcomputer 111 when it does not receive the lens data signal DLC (DL10 in the figure) from the lens microcomputer 111 even if it asserts the transmission request signal RTS. Stop communication without Note that the camera microcomputer 205 maintains the transmission request signal RTS in an asserted state during the communication stop period T2w2 as instructed by the lens microcomputer 111 .

After that, the communication stop request event disappears in the lens microcomputer 111, and the lens microcomputer 111 resumes transmission of the restart frame DL10 of the lens data signal DLC. The camera microcomputer 205 restarts transmission of the corresponding frame DC10 in the camera data signal DCL in response to detecting the start bit ST of the restart frame DL10.

Next, a problem that may occur when there is a difference between the bit rate of the camera data signal DCL output by the camera microcomputer 205 and the bit rate of the lens data signal DLC output by the lens microcomputer 111 in the non-BUSY addition mode will be described with reference to FIG. ) will be used to explain. FIG. 9A shows a case where the bit lengths of one frame (data frame) of the camera data signal DCL and the lens data signal DLC are the same, and the bit rate of the camera data signal DCL is slower than that of the lens data signal DLC. 2 shows the relationship between frames of data signals DCL and DLC. Arrows in the drawing indicate which start bit ST in the lens data signal DLC the camera microcomputer 205 detects and which frame in the camera data signal DCL is transmitted to the camera microcomputer 205 .

Since the bit rate of the frame of the camera data signal DCL is slower than that of the lens data signal DLC, the delay gradually increases with respect to the frame of the lens data signal DLC. Since continuous data communication is performed, there is no gap (non-communication time) between frames. Therefore, by accumulating the delay, the difference between the two data signals DCL and DLC becomes one frame or more, resulting in a difference in the number of transmitted frames of the two data signals DCL and DLC. In addition, the camera microcomputer 205 detects the start bit ST of the lens data signal DLC by skipping one frame, thereby generating a period during which the camera data signal DCL is not transmitted for about one frame. If such a situation occurs, it becomes difficult to manage the amount of data communicated between the camera microcomputer 205 and the lens microcomputer 111, or the data communication fails.

Therefore, in this embodiment, as shown in FIGS. 5A and 9B, the number of stop bits SP, which are the last bit of each frame of the lens data signal DLC, is changed to The number is greater than the number of stop bits ST. Specifically, the number of stop bits ST for each frame of the camera data signal DCL is one, while the number of stop bits SP for each frame of the lens data signal DLC is two. The data format of the lens data signal DLC and the data format of the camera data signal DCL are the same except for the difference in the number of stop bits. Due to this difference in the number of stop bits, the number of bits in one frame (a data frame of) of the lens data signal DLC becomes larger than the number of bits in one frame of the camera data signal DCL. In other words, the bit length of one frame of the lens data signal DLC is longer than the bit length of one frame of the camera data signal DCL. As a result, even when the bit rate of the camera data signal DCL is slower than that of the lens data signal DLC signal, it is possible to prevent the deviation of the frame of the camera data signal DCL from accumulating with respect to the frame of the lens data signal DLC signal. can be done.

Since the bit length of one frame of the lens data signal DLC is longer than the bit length of one frame of the camera data signal DCL, when the bit rates of both data signals DCL and DLC are the same, the camera data signal DCL is transmitted faster. Completed. Furthermore, even if the bit rate of the camera data signal DCL is slower than that of the lens data signal DLC due to bit rate error, 1 bit as the bit length difference of one frame absorbs the difference in transmission time for each frame due to bit rate error. It is a sufficient margin for

Note that if the bit rate of the camera data signal DCL is faster than that of the lens data signal DLC, the above-described frame shift problem does not occur. This is because the frame of the camera data signal DCL is set to be transmitted in response to detecting the start bit ST of the frame of the lens data signal DLC. Also, even if the bit rates that can be set between the camera body 200 and the interchangeable lens 100 are slightly different, it is possible to deal with this by further increasing the bit number of the stop bits SP of the lens data signal DLC.

As described above, in this embodiment, in the BUSY addition mode in the first communication setting, the camera microcomputer 205 can notify the lens microcomputer 111 to stop communication by negating the transmission request signal RTS. Further, the lens microcomputer 111 can notify the camera microcomputer 205 of communication stop by adding a communication standby request BUSY (BUSY frame) to the lens data signal DLC. As a result, the camera microcomputer 205 and the lens microcomputer 111 can communicate data smoothly and at high speed. On the other hand, in the non-busy addition mode in the first communication setting, the camera microcomputer 205 negates the transmission request signal RTS during burst communication from the lens microcomputer 111 to the camera microcomputer 205, thereby requesting the lens microcomputer 111 to stop communication. can be notified. As a result, the camera microcomputer 205 and the lens microcomputer 111 can communicate a large amount of data at high speed while maintaining synchronization.

Next, a second communication setting between the camera microcomputer 205 and the lens microcomputer 111 will be described. In the second communication setting, as shown in FIG. 6, the second data communication channel is switched from the lens microcomputer 111 to the camera microcomputer 205 by switching the communication direction (communication setting) in the communication interface circuits 208a and 112a. Used for data transmission. That is, in the signal circuit of the second data communication channel, the input/output buffers are configured in parallel so that the input/output direction can be switched, and can be selected exclusively. In the following description, lens data transmitted as a signal from the lens microcomputer 111 to the camera microcomputer 205 through the second data communication channel is referred to as a second lens data signal DLC2. In order to distinguish the lens data signal DLC, which is transmitted from the lens microcomputer 111 to the camera microcomputer 205 through the first data communication channel together with the transmission of the second lens data signal DLC2, from the second lens data signal DLC2, the first is called a lens data signal DLC.

In the second communication setting, both the first and second data communication channels are used for continuous communication (burst communication) of lens data signals to the camera microcomputer 205 . This makes it possible to communicate a large amount of data at a higher speed than in the non-BUSY addition mode in the first communication setting.

However, when switching from the first communication setting to the second communication setting, the camera data signal DCL transmitted from the camera microcomputer 205 and the lens data signal DLC2 transmitted from the lens microcomputer 111 through the second data communication channel collision should be avoided. Therefore, in this embodiment, the camera microcomputer 205 and the lens microcomputer 111 perform communication setting switching processing as described below.

7 shows the configuration of the camera data transmission/reception unit 208b in the camera microcomputer 205 and the lens data transmission/reception unit 112b in the lens microcomputer 111. As shown in FIG. In FIG. 7, constituent elements common to those shown in FIG. 3 are denoted by the same reference numerals as in FIG. In the camera data transmission/reception unit 208b, 1401 is a communication direction switching unit. A communication direction switching unit 1401 switches the communication direction of the second data communication channel to the direction in which the camera microcomputer 205 receives the second lens data signal DLC2 transmitted from the lens microcomputer 111 by switching the switch 1402 . Thereafter, the camera microcomputer 205 converts the second lens data signal DLC2 received from the lens microcomputer 111 through the second data communication channel from serial data to parallel data in the serial-parallel conversion unit 306, and converts the data into the received data buffer 303. store in The received data buffer 303 also stores the first lens data signal DLC received through the first data communication channel and converted from serial data to parallel data by the serial-parallel converter 306 . The second lens data signal DLC2 stored in the reception data buffer 303 is read by the DMA control unit 307, transferred to the memory 210, and stored.

In the lens data transmission/reception section 112b, 1411 is a communication direction switching section. A communication direction switching unit 1411 switches the communication direction of the second data communication channel to the direction in which the lens microcomputer 111 transmits the second lens data signal DLC2 to the camera microcomputer 205 by switching the switch 1412 . Thereafter, the lens microcomputer 111 converts the second lens data signal DLC2 stored in the transmission data buffer 312 from parallel data to serial data in the parallel-serial conversion unit 315, and transmits the data to the camera microcomputer 205 through the second data communication channel. Send to The lens microcomputer 111 converts the first lens data signal DLC stored in the transmission data buffer 312 from parallel data to serial data in the parallel-serial conversion unit 315, and transmits the data to the camera microcomputer 205 through the first data communication channel. Send.

Next, a communication procedure in the second communication setting will be described. FIG. 8A shows waveforms of signals exchanged between the camera microcomputer 205 and the lens microcomputer 111 in the second communication setting. FIG. 8A shows signal waveforms when one frame, which is the minimum communication unit, is continuously communicated for three frames.

In the second communication setting, each frame of the first and second lens data signals DLC, DLC2 is composed only of data frames and does not contain BUSY frames, as in the non-BUSY addition mode in the first communication setting. . That is, the first and second lens data signals DLC and DLC2 have a data format that does not allow the lens microcomputer 111 to notify the camera microcomputer 205 of the communication standby request BUSY. The second communication setting is specialized as a communication setting used only for data transfer from the lens microcomputer 111 to the camera microcomputer 205. Data transfer is not possible. Also, the first and second lens data signals DLC and DLC2 are generated without leaving a space between the stop bit SP of the previous frame and the start bit ST of the next frame, as in the non-BUSY addition mode in the first communication setting. It has a data format that allows continuous communication.

The data frames of the first and second lens data signals DLC and DLC2 have the same data format, and the bit length of one frame is the same. The purpose of this is to manage the number of transmitted frames as the same when a stop occurs during these communications. However, the relative relationship between the bit positions of the data frames of the first and second lens data signals DLC and DLC2 does not necessarily have to be the same, and it is permissible as long as the amount of deviation between the bit positions does not exceed the length of one frame. be done.

FIG. 8B shows the case where the lens microcomputer 111 continuously transmits the first and second lens data signals DLC and DLC2 of a total of n frames to the camera microcomputer 205 in the second communication setting (ie burst communication). ) shows the waveform of the signal.

When an event for starting communication with the lens microcomputer 111 occurs, the camera microcomputer 205 asserts the transmission request signal RTS. After that, the camera microcomputer 205 does not need to negate the transmission request signal RTS for each frame, and maintains the asserted state of the transmission request signal RTS as long as the continuous data transmission/reception is possible.

Upon detecting a transmission request by asserting the transmission request signal RTS, the lens microcomputer 111 generates the first and second lens data signals DLC and DLC2 to be transmitted to the camera microcomputer 205 . Then, when preparations for transmission of these first and second lens data signals DLC and DLC2 are completed, transmission of the first frame DL1 of the first lens data signal DLC to the camera microcomputer 205 through the first data communication channel is performed. Start. At the same time, transmission of the second frame DL2 of the second lens data signal DLC2 to the camera microcomputer 205 through the second data communication channel is started.

After completing the transmission of the first and second frames DL1 and DL2 of the first and second lens data signals DLC and DLC2, the lens microcomputer 111 checks the state of the transmission request signal RTS. When the transmission request signal RTS is in an asserted state, the lens microcomputer 111 continuously outputs the first and second frames DL3 and DL4 of the first and second lens data signals DLC and DLC2 to the cameras of the third and fourth frames DL3 and DL4. Transmission to the microcomputer 205 is started. In this manner, the camera microcomputer 205 maintains the asserted state of the transmission request signal RTS, thereby allowing the lens microcomputer 111 to continuously transmit the first and second lens data signals DLC and DLC2 to the camera microcomputer 205 for a total of n frames. can send.

By setting the total number of frames n of the first and second lens data signals DLC and DLC2 to be an even number, the number of frames transmitted from the lens microcomputer 111 to the camera microcomputer 205 through each of the first and second data communication channels is be the same number. In FIG. 8B, the first lens data signal DLC transmitted through the first data communication channel is composed only of odd-numbered frames, and the second lens data signal DLC transmitted through the second data communication channel is DLC2 was composed only of even frames. However, the first and second lens data signals DLC and DLC2 may have frame configurations other than this.

FIG. 8(C) shows the state in which the camera microcomputer 205 and the lens microcomputer 111 instruct to stop communication during continuous transmission of the first and second lens data signals DLC and DLC2 shown in FIG. 8(B). Signal waveforms are shown. After the lens microcomputer 111 starts transmitting the first and second lens data signals DLC and DLC2 in response to the assertion of the transmission request signal RTS by the camera microcomputer 205, the camera microcomputer 205 stops communication during transmission of the frames DL11 and DL12. is indicated. T4w1 indicates a communication stop period during which the camera microcomputer 205 instructs to stop communication. The instruction is notified to the lens microcomputer 111 by the camera microcomputer 205 temporarily negating the transmission request signal RTS.

When the lens microcomputer 111 detects that the transmission request signal RTS has been negated, the frames of the first and second lens data signals DLC and DLC2 which are being transmitted at the time of detection (hereinafter referred to as stop frames) DL11 and DL12 are deleted. After completing the transmission, stop the transmission.

When the request event for communication stop disappears, the camera microcomputer 205 instructs the lens microcomputer 111 to resume communication by asserting the transmission request signal RTS again. In response to the communication restart instruction, the lens microcomputer 111 restarts transmission of the first and second lens data signals DLC, DLC2 from frames DL13, DL14 next to the stop frame (hereinafter referred to as restart frames).

The lens microcomputer 111 sequentially transmits the restart frames DL13 and DL14, the subsequent frames DL15 and DL16, and the frames DL17 and DL18 in this order. When the transmission of the frames DL17 and DL18 is completed, the lens microcomputer 111 notifies the camera microcomputer 205 of communication stop by generating a communication stop request event. T4w2 represents a communication stop period during which the lens microcomputer 111 notifies the communication stop. The communication stop notification from the lens microcomputer 111 is performed by the lens microcomputer 111 not transmitting the first and second lens data signals DLC and DLC2 even when the transmission request signal RTS is asserted. Note that the camera microcomputer 205 maintains the transmission request signal RTS in an asserted state during the communication stop period T4w2 as instructed by the lens microcomputer 111 .

After that, when the communication stop request event within the lens microcomputer 111 disappears, the lens microcomputer 111 resumes transmission of the first and second lens data signals DLC and DLC2 to the camera microcomputer 205 from the next restart frames DL19 and DL20. do. As a result, the lens microcomputer 111 can transmit to the camera microcomputer 205 those frames of the first and second lens data signals DLC and DLC2 that have not been transmitted due to the suspension of transmission.

Thus, in the second communication setting, by stopping the transmission of the first and second lens data signals DLC and DLC2 from the lens microcomputer 111 to the camera microcomputer 205, the communication between the camera microcomputer 205 and the lens microcomputer 111 is stopped. can stop communication between As a result, a large amount of data can be communicated at high speed from the lens microcomputer 111 to the camera microcomputer 205 while maintaining synchronization.

As described above, in this embodiment, both the camera microcomputer 205 and the lens microcomputer 111 can instruct to stop and restart communication in both the first and second communication settings. Therefore, communication control can be performed according to the processing load of both the camera microcomputer 205 and the lens microcomputer 111 and the capacity of the reception buffer, and a large amount of data can be communicated at high speed without causing communication failure. .

Next, Example 2 of the present invention will be described. In this embodiment, the continuous transmission (burst communication) of the first and second lens data signals DLC and DLC2 from the lens microcomputer 111 to the camera microcomputer 205 in the second communication setting described in the first embodiment is forcibly stopped. explain.

In the second communication setting described in the first embodiment, both the first and second data communication channels are used for transmitting the first and second lens data signals DLC, DLC2 from the lens microcomputer 111 to the camera microcomputer 205. This enables high-speed communication of large amounts of data. However, since the second data communication channel for communication of the camera data signal DCL is originally used for communication of the second lens data signal DLC2, the camera microcomputer 205 sends a control command to the lens microcomputer 111 during the communication. Inability to notify instructions by Therefore, even if the camera microcomputer 205 recognizes a communication abnormality during burst communication, the camera microcomputer 205 cannot instruct the lens microcomputer 111 to forcibly stop communication. The communication abnormality referred to here includes data corruption due to static electricity, and a communication channel between the camera microcomputer 205 and the lens microcomputer 111 being cut off due to sudden removal of the interchangeable lens from the camera body by the user.

When such a communication abnormality occurs, it is desirable to forcibly stop communication immediately. However, in the second communication setting, after the burst communication from the lens microcomputer 111 to the camera microcomputer 205 is completed, the second data communication channel is switched to the communication of the camera data signal DCL and the forced stop is notified. slows down the stop. In this embodiment, it is possible to forcibly stop communication immediately when such a communication abnormality occurs.

FIG. 10 shows the configuration of a camera system including a camera body 200' and an interchangeable lens 100' in this embodiment. In the camera system of this embodiment, the same components as those of the camera system shown in Embodiment 1 (FIG. 1) are denoted by the same reference numerals as in Embodiment 1, and the description thereof is omitted.

In FIG. 10, the timer 114 provided in the interchangeable lens 100' measures the time from the time count start command to the time count end command from the lens microcomputer 111. FIG. The lens microcomputer 111 outputs a time count start command to the timer 114 in response to negation of the transmission request signal RTS from the camera microcomputer 205, and causes the timer 114 to count time in response to the assertion of the transmission request signal RTS. Output a termination command. As a result, the time during which the transmission request signal RTS is negated (hereinafter referred to as lens side RTS negation time) is measured, and information on the lens side RTS negation time is input to the lens microcomputer 111 .

On the other hand, a timer 211 provided in the camera body 200 ′ measures the time from the time count start command from the camera microcomputer 205 . The camera microcomputer 205 negates the transmission request signal RTS and outputs a time count start command to the timer 211 . As a result, the time during which the camera microcomputer 205 negates the transmission request signal RTS (hereinafter referred to as camera side RTS negation time) is measured, and information on the camera side RTS negation time is input to the camera microcomputer 205 .

Processing for communication control in this embodiment will be described with reference to the flowchart of FIG. The camera microcomputer 205 and lens microcomputer 111 execute this process according to a communication control program as a computer program. Here, a case of forcibly stopping communication when using the second communication setting described in the first embodiment will be described. However, communication may be forcibly stopped when the first communication setting is used. Also, the processing shown in FIG. 11 starts from a state in which the first communication setting is set. In FIG. 11 and the following description, "S" means step.

In S1101, the camera microcomputer 205 prepares a burst communication request command. The burst communication request command includes information necessary for the lens microcomputer 111 to perform burst communication, such as communication data amount and bit rate in burst communication. Then, in S1102, the camera microcomputer 205 transmits a burst communication request command to the lens microcomputer 111 through the second data communication channel as the camera data signal DLC.

Upon receiving the burst communication request command, the lens microcomputer 111 generates the first and second lens data signals DLC and DLC2 according to the information included in the burst communication request command and converts the first communication setting to the second lens data signal in S1201. prepares for communication, including switching to the communication settings of Then, when communication is ready, the lens microcomputer 111 transmits a preparation completion notification to the camera microcomputer 205 as the first camera data signal DLC through the first data communication channel in S1202.

The camera microcomputer 205 that has received the preparation completion notification asserts a transmission request signal RTS in S1104 in response to completion of communication preparation in the camera microcomputer 205 in S1103 to notify the lens microcomputer 111 of a transmission request. Upon receiving the transmission request, the lens microcomputer 111 continuously transmits (burst communication) the first and second lens data signals DLC and DLC2 to the camera microcomputer 205 through the first and second data communication channels in S1203 and S1204, respectively. ).

During this burst communication, the camera microcomputer 205 constantly monitors whether or not a communication error occurs. Here, in S1105, it is assumed that the camera microcomputer 205 detects that a communication error has occurred while receiving the first lens data signal DLC or the second lens data signal DLC2. A communication error can be detected by determining whether there is a discrepancy between the parity information PA added to each frame and the received data content, as shown in FIG. 8(A). In addition to this, a communication error can also be detected by not being able to detect the stop bit ST of each frame normally. Furthermore, the communication error also includes a case where the interchangeable lens 100 is suddenly removed from the camera body 200 by the user and communication becomes impossible. The camera microcomputer 205 that has detected the communication error advances to S1106. The camera microcomputer 205 that has not detected a communication error continues receiving the first and second lens data signals DLC and DLC2.

In S1106, the camera microcomputer 205 gives a time count start command to the timer 211 to start measuring the RTS negate time on the camera side. Then, in S1107, the camera microcomputer 205 negates the transmission request signal RTS to instruct the lens microcomputer 111 to stop transmitting the first and second lens data signals DLC and DLC2.

Upon detecting negation of the transmission request signal RTS, the lens microcomputer 111 stops transmission of the first and second lens data signals DLC and DLC2 in S1205. Further, in S1206, the lens microcomputer 111 issues a time count start command to the timer 114 to start measuring the RTS negate time on the lens side.

The lens microcomputer 111 determines whether or not the lens-side RTS negate time measured by the timer 114 has exceeded a predetermined time A in S1207. The predetermined time A may be set in advance as a communication standard between the camera microcomputer 205 and the lens microcomputer 111 . Further, the predetermined time A may be notified to the lens microcomputer 111 by transmitting the burst communication request command from the camera microcomputer 205 to the lens microcomputer 111 in S1102 or by the camera data signal DCL transmitted subsequently. A specific example of the predetermined time A will be described later in a third embodiment. If the transmission request signal RTS is asserted by the camera microcomputer 205 before the lens side RTS negate time exceeds the predetermined time A, the lens microcomputer 111 resumes transmission of the first and second lens data signals DLC and DLC2. .

When the camera side RTS negate time exceeds the predetermined time A in S1108, the camera microcomputer 205 asserts the transmission request signal RTS in S1109. Accordingly, the camera microcomputer 205 instructs the lens microcomputer 111 to forcibly stop transmission of the first and second lens data signals DLC and DLC2. When the lens microcomputer 111 detects the assertion of the transmission request signal RTS after the lens-side RTS negate time exceeds the predetermined time A, this is an instruction to forcibly stop the transmission of the first and second lens data signals DLC and DLC2. I judge. Then, in S1208, the lens microcomputer 111 stops transmission of the first and second lens data signals DLC and DLC2 halfway through, and in S1209, the camera microcomputer 205 receives a notification command to transmit the first lens data signal DLC to the camera microcomputer 205. Notifies completion of forced stop.

The camera microcomputer 205 that has received the forced stop completion notification from the lens microcomputer 111 ends receiving the first and second lens data signals DLC and DLC2 from the lens microcomputer 111 in S1110. Then, the camera microcomputer 205 switches the second data communication channel from a state capable of receiving the second lens data signal DLC2 to a state capable of transmitting the camera data signal DCL.

In FIG. 12A, the first and second lens data signals DLC and DLC2 of a total of n frames (DL1 to DLn) are transmitted from the lens microcomputer 111 to the camera microcomputer 205 in the second communication setting during a communication stop period. A signal waveform when continuously transmitted across T4w1 is shown. In response to assertion of the transmission request signal RTS by the camera microcomputer 205, the lens microcomputer 111 starts transmitting the first and second lens data signals DLC and DLC2. After that, while the frames DL11 and DL12 are being transmitted from the lens microcomputer 111, the camera microcomputer 205 temporarily negates the transmission request signal RTS, thereby instructing the lens microcomputer 111 to stop communication. When the lens microcomputer 111 detects that the transmission request signal RTS has been negated, the frames of the first and second lens data signals DLC and DLC2 which are being transmitted at the time of detection (hereinafter referred to as stop frames) DL11 and DL12 are deleted. After completing the transmission, stop the transmission. From this point, measurement of the communication stop period T4w1, that is, the RTS negation time on the camera side and the lens side starts.

When the communication stop request event disappears before the communication stop period T4w1 exceeds the predetermined time A, the camera microcomputer 205 instructs the lens microcomputer 111 to resume communication by asserting the transmission request signal RTS again. In response to the communication restart instruction, the lens microcomputer 111 restarts transmission of the first and second lens data signals DLC and DLC2 from the restart frames DL13 and DL14 next to the stop frame.

On the other hand, FIG. 12B shows waveforms of signals exchanged between the camera microcomputer 205 and the lens microcomputer 111 when the communication stop period T4w1 described in FIG. 12A exceeds the predetermined time A. When the communication stop period T4w1 (camera-side RTS negate time) exceeds a predetermined time A, the camera microcomputer 205 asserts the transmission request signal RTS, which has been negated up to that point, thereby forcibly stopping communication with the lens microcomputer 111. to direct. The lens microcomputer 111 detects the assertion of the transmission request signal RTS when the communication stop period T4w1 (lens-side RTS negate time) exceeds the predetermined time A, and determines that this is an instruction for the camera microcomputer 205 to forcibly stop communication. In response to this, the lens microcomputer 111 stops transmission of the first and second lens data signals DLC, DLC2 by transmission up to the stop frames DL11, DL12. Furthermore, the lens microcomputer 111 notifies the camera microcomputer 205 of forced stop completion (END) by a notification command transmitted as the first lens data signal DLC. The forced stop completion notification may be made in one frame or may be made in a plurality of frames. Thus, the lens microcomputer 111 clears the untransmitted frames DL13 to DLn without transmitting them to the camera microcomputer 205 .

Thus, when a communication error occurs during burst communication from the lens microcomputer 111 in the second communication setting, the camera microcomputer 205 can quickly instruct the lens microcomputer 111 to forcibly stop the burst communication. .

In this embodiment, the case where the assertion of the transmission request signal RTS after the RTS negation time on the camera side and the lens side exceeds the predetermined time A is simply an instruction to forcibly stop burst communication. However, the assertion of this transmission request signal RTS may be used as an instruction to restart burst communication (forced stop and restart from the beginning).

Next, Example 3 of the present invention will be described. This embodiment also relates to forced stop of continuous transmission (burst communication) of the first and second lens data signals DLC and DLC2 from the lens microcomputer 111 to the camera microcomputer 205 in the second communication setting.

As described with reference to FIG. 7 in the first embodiment, the first and second lens data signals DLC and DLC2 stored in the received data buffer 303 under the second communication setting are received by the DMA controller 307. The data is read from the data buffer 303 and transferred to the memory 210 . This is because the capacity of the received data buffer 303 is insufficient for the amount of data for all frames of the first and second lens data signals DLC and DLC2. However, since the memory 210 is accessed not only by the camera communication unit 208 but also by the signal processing circuit 203 shown in FIG. At this time, if the camera microcomputer 205 cannot instruct the lens microcomputer 111 to stop the burst communication, the burst communication may fail.

FIG. 13 shows an example of the predetermined time A until the camera microcomputer 205 instructs to forcibly stop the burst communication from the lens microcomputer 111 to the camera microcomputer 205 in this embodiment. The predetermined time A is set according to the amount of data in burst communication. In this example, when the amount of data in burst communication is equal to or less than the capacity of the received data buffer (Rx_RAM) 303, the predetermined period A is set to 0 ms. Also, when the amount of data in burst communication exceeds the capacity of the received data buffer (Rx_RAM) 303, the predetermined period A is set to 20 ms. The predetermined time A can be arbitrarily set according to the capacity of the received data buffer 303 and the processing capability of the camera microcomputer 205 . Also, the predetermined time A may be uniformly set regardless of the capacity of the received data buffer 303 or the like.

Table information indicating the predetermined time A with respect to the data amount of burst communication may be stored in the internal memory of the camera microcomputer 205, the memory 210, or the like. As a result, the camera microcomputer 205 can notify the setting of the predetermined time A to the lens microcomputer 111 before starting burst communication.

Also, similar table information is stored in the internal memory of the lens microcomputer 111 or the like, and the predetermined time A is determined according to the amount of data transmitted by the lens microcomputer 111 to the camera microcomputer 205 by burst communication before starting burst communication. may In this case, the camera microcomputer 205 does not need to notify the lens microcomputer 111 of the setting of the predetermined time A.

When the predetermined time A is set to 0 ms, when the transmission request signal RTS is asserted from the negated state, the lens microcomputer 111 determines that it is not an instruction to resume communication but an instruction to forcibly stop communication. On the other hand, when the predetermined time A is set to 20 ms, the lens microcomputer 111 determines that the transmission request signal RTS is asserted from the negated state within the predetermined time A as an instruction to resume communication. However, when the transmission request signal RTS is asserted from the negated state after the predetermined time A has passed, it is determined that this is an instruction to forcibly stop communication.

According to this embodiment, when the capacity of the received data buffer 303 has a margin for the data amount of burst communication, the time required to forcibly stop burst communication can be shortened compared to the second embodiment. . Therefore, during burst communication with the second communication setting, when the camera microcomputer 205 detects a communication error, it is possible to quickly instruct the lens microcomputer 111 to forcibly stop the burst communication. Therefore, the camera microcomputer 205 can quickly cause the lens microcomputer 111 to restart burst communication.

A fourth embodiment of the present invention will be described below. In this embodiment, as shown in FIG. 15, the camera body 200″ has a memory controller 212 that controls a memory (DDR) 210. Note that FIG. 208 is shown separately from the camera microcomputer 205. The camera main body 200'' of this embodiment corresponds to the camera main body 200' described in the second embodiment with a memory controller 212 added thereto. The interchangeable lens 100' of is the same as that described in the second embodiment.

Memory controller 212 will be described. In FIG. 15, a bus IF 506 is a bus interface module that interfaces with a master module requesting memory access inside the chip. The master module refers to the main processing units in the camera body 200″ such as the camera microcomputer 205 and the signal processing circuit 203. The figure shows a configuration that can be connected to two buses of the same or different types.

The arbiter unit 501 arbitrates and orders memory access requests to the memory 210 received by the bus IF 506 . The queue buffer 502 is used as a buffer that can temporarily store memory access requests ordered by the arbiter unit 501 . The camera microcomputer 205 obtains information on the frequency of memory access requests (hereinafter referred to as memory access frequency) from the memory access requests stored in the queue buffer 502 .

The command issuing unit 503 sequentially retrieves the memory access requests stored in the queue buffer 502, and accesses the memory 210 based on the contents thereof. The data IF 504 is an interface for reading data from and writing data to the memory 210 in response to a memory access request issued by the command issuing unit 503 .

For example, when the memory access request selected by the arbiter unit 501 is a command requesting data writing to the memory 210 , the data control unit 505 acquires write data from the bus interface 1 . The data control unit 505 saves the fetched write data until the actual data write timing, and outputs it to the data IF 504 . Further, when the memory access request selected by the arbiter unit 501 is a command requesting data read to the memory 210 , the data control unit 505 outputs the data read from the memory 210 to the data IF 504 .

In the present embodiment, when the camera body 200'' has the memory controller 212, the communication by the camera microcomputer 205 that detects a communication abnormality during burst communication from the lens microcomputer 111 to the camera microcomputer 205 under the second communication setting is performed. 14 shows the communication control processing between the camera microcomputer 205 and the lens microcomputer 111. The camera microcomputer 205 and the lens microcomputer 111 are computer programs for communication control programs. Do this according to

In S401 in FIG. 14, the camera microcomputer 205 acquires memory access frequency information from the memory controller 212 (queue buffer 502). High memory access frequency means that the memory access request waiting time is long from the time when the first memory access request is made to the time when the camera communication unit 208 can receive the burst communication from the lens microcomputer 111 . do.

Next, in S402, the camera microcomputer 205 uses the memory access frequency acquired in S401 to determine whether or not the shooting mode currently set in the camera body 200'' is the shooting mode in which the memory access frequency of the camera communication unit 208 is high. If so, the process advances to S403, and if the shooting mode has a low memory access frequency, the process advances to S404.

In S403, the camera microcomputer 205 negates the transmission request signal RTS and sets a predetermined time A, which is the upper limit of the time to stop communication (hereinafter referred to as RTS negation time), in accordance with the high memory access frequency. Set longer than the time set in . In S404, the camera microcomputer 205 sets the predetermined time A to a time shorter than the time set in S403 in accordance with the low memory access frequency. That is, when the memory access request waiting time is long, the predetermined time A is set long, and when the memory access request waiting time is short, the predetermined time A is set short.

Next, in S405, the camera microcomputer 205 transmits a burst communication request command as the camera data signal DLC to the lens microcomputer 111 through the second data communication channel. The burst communication request command includes information necessary for the lens microcomputer 111 to perform burst communication, such as communication data amount and bit rate in burst communication.

Upon receiving the burst communication request command, the lens microcomputer 111 generates the first and second lens data signals DLC and DLC2 in accordance with the information included in the burst communication request command and converts the first communication setting to the second lens data signal in S406. Prepare for communication, including switching to communication settings. Then, when communication preparation is complete, the lens microcomputer 111 transmits a preparation completion notification to the camera microcomputer 205 as the first camera data signal DLC through the first data communication channel.

The camera microcomputer 205 that has received the preparation completion notification asserts the transmission request signal RTS and notifies the lens microcomputer 111 of the transmission request in response to the completion of communication preparation in the camera microcomputer 205 in S407. Upon receiving the transmission request, the lens microcomputer 111 starts continuous transmission (burst communication) of the first and second lens data signals DLC and DLC2 to the camera microcomputer 205 through the first and second data communication channels.

During this burst communication, the camera microcomputer 205 constantly monitors whether or not a communication error occurs. The communication error detection is as described in S1105 in the second embodiment. If no communication error is detected, the camera microcomputer 205 proceeds to S412.

On the other hand, if a communication error is detected, the camera microcomputer 205 negates the transmission request signal RTS in S408 to instruct the lens microcomputer 111 to stop transmitting the first and second lens data signals DLC and DLC2. do. Upon detecting negation of the transmission request signal RTS, the lens microcomputer 111 stops transmission of the first and second lens data signals DLC and DLC2, and gives a time count start command to the timer 114 to start measuring the RTS negation time. Let

The lens microcomputer 111 determines whether or not the RTS negate time measured by the timer 114 has exceeded the predetermined time A in S409. If the RTS negate time has not exceeded the predetermined time A, the lens microcomputer 111 advances to S410 to determine whether the camera microcomputer 205 has asserted the communication request signal RTS again. When the communication request signal RTS is asserted, the lens microcomputer 111 restarts transmission of the first and second lens data signals DLC and DLC2 in S411. Then, in S412, the lens microcomputer 111 determines whether transmission of all frames of the first and second lens data signals DLC and DLC2 to be transmitted to the camera microcomputer 205 has been completed. If so, this process ends. If the communication request signal RTS is not asserted in S410, the lens microcomputer 111 returns to S409.

If the RTS negate time measured by the timer 114 exceeds the predetermined time A in S409, the lens microcomputer 111 proceeds to S413 to determine whether the camera microcomputer 205 has asserted the communication request signal RTS again. When the communication request signal RTS is asserted, the lens microcomputer 111 stops transmitting the first and second lens data signals DLC and DLC2 in S414. That is, the untransmitted frames of the first and second lens data signals DLC and DLC2 are not transmitted to the camera microcomputer 205, but are cleared. Then, the lens microcomputer 111 notifies the camera microcomputer 205 of the forced stop completion by a notification command transmitted as the first lens data signal DLC. The camera microcomputer 205 switches from the state corresponding to the second communication setting to the state corresponding to the first communication setting, and ends this process.

In this manner, when the communication request signal RTS is re-asserted before the RTS negation time exceeds the predetermined time A, the lens microcomputer 111 determines that this is an instruction to resume the burst communication, and the interrupted burst communication is resumed. to resume. On the other hand, when the communication request signal RTS is re-asserted after the RTS negate time exceeds the predetermined time A, this is determined as an instruction to forcibly stop burst communication, and burst communication is terminated.

16A and 16B show an RTS negation time during the continuous transmission of the first and second lens data signals DLC and DLC2 from the lens microcomputer 111 to the camera microcomputer 205 in the second communication setting. 4 shows signal waveforms when the communication stop period T4w1 as is inserted. The first and second lens data signals DLC and DLC2 originally have a total of n frames (DL1 to DLn) as shown in FIG. 16(B).

In these figures, the lens microcomputer 111 starts transmitting the first and second lens data signals DLC and DLC2 in response to the camera microcomputer 205 asserting the transmission request signal RTS. After that, while the frames DL11 and DL12 are being transmitted from the lens microcomputer 111, the camera microcomputer 205 temporarily negates the transmission request signal RTS, thereby instructing the lens microcomputer 111 to stop communication. When the lens microcomputer 111 detects that the transmission request signal RTS has been negated, the frames of the first and second lens data signals DLC and DLC2 which are being transmitted at the time of detection (hereinafter referred to as stop frames) DL11 and DL12 are deleted. After completing the transmission, stop the transmission. From here, measurement of the communication stop period T4w1, that is, the RTS negate time starts.

FIG. 16A shows a case where the predetermined time A is set to a long time because the shooting mode is a shooting mode in which the memory access frequency of the camera communication unit 208 is high. On the other hand, FIG. 16B shows a case where the predetermined time A is set to a short time because the shooting mode is a shooting mode in which the memory access frequency of the camera communication unit 208 is low.

As shown in FIG. 16A, when the camera microcomputer 205 asserts the transmission request signal RTS again after the communication stop period T4w1 exceeds the predetermined time A, the lens microcomputer 111 takes this as an instruction to forcibly stop communication. to decide. In response to this, the lens microcomputer 111 stops transmitting the first and second lens data signals DLC and DLC2 by transmitting up to the stop frames DL11 and DL12. Further, the lens microcomputer 111 notifies the camera microcomputer 205 of forced stop completion (END) by a notification command transmitted as the first lens data signal DLC. The forced stop completion notification may be made in one frame or may be made in a plurality of frames. Thus, the lens microcomputer 111 clears the untransmitted frames DL13 to DLn without transmitting them to the camera microcomputer 205 .

On the other hand, as shown in FIG. 16B, when the camera microcomputer 205 asserts the transmission request signal RTS again before the communication suspension period T4w1 exceeds the predetermined time A, the lens microcomputer 111 takes this as an instruction to resume communication. to decide. In response to this, the lens microcomputer 111 resumes transmission of the first and second lens data signals DLC, DLC2 from the restart frames DL13, DL14 next to the stop frame.

As described above, in the present embodiment, the communication stoppage occurs due to the difference in memory access request waiting time caused by the difference in frequency of memory access to the memory 210 that finally stores the first and second lens data signals DLC and DLC2. The upper limit time (predetermined time A) is variable. As a result, it is possible to set an optimum upper limit time of communication stop according to the storage speed of the first and second lens data signals DLC and DLC2 in the memory 210. FIG. Therefore, after the communication error is detected in the camera body 200″ and the communication is stopped, the lens microcomputer 111 can quickly determine whether to forcibly stop the communication or restart the communication.

In this embodiment, the case where the assertion of the transmission request signal RTS after the RTS negation time exceeds the predetermined time A is simply an instruction to forcibly stop burst communication. However, the assertion of this transmission request signal RTS may be used as an instruction to restart burst communication (forced stop and restart from the beginning). Also, when the RTS negate time is likely to exceed the predetermined time A, the priority of the access request from the camera microcomputer 205 (camera communication unit 208) to the memory 210 is raised, and the burst communication from the lens microcomputer 111 is performed within the predetermined time A. You may control it so that it can be completed.
(Other examples)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.
Each embodiment described above is merely a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

100 interchangeable lens 111 lens microcomputer 200 camera body 205 camera microcomputer

Claims (34)

An accessory device removably attached to an imaging device, comprising:
having accessory control means for controlling communication between the accessory device and the imaging device;
In the first mode, the accessory control means causes the signal level of the first channel to change from the second signal level to the second signal level after the signal level of the first channel changes from the first signal level to the second signal level. responsive to being maintained at a level, communicating with the imaging device via a second channel and a third channel ;
The accessory device, wherein the accessory control means stops transmission of the accessory data in response to a change in the signal level of the first channel from the second signal level to the first signal level. . When the signal level of the first channel changes from the second signal level to the first signal level in a state in which transmission of accessory data of a certain frame is incomplete , the accessory control means controls the 2. The accessory device of claim 1 , wherein transmission of the accessory data to the imaging device is stopped after frame transmission is completed. The accessory control means performs transmission of the accessory data via the second channel and the 3. An accessory device according to claim 1 or 2 , wherein the accessory device receives camera data via a third channel. The accessory control means performs transmission of the accessory data and transmission of the accessory data via the second channel as the communication performed in response to the signal level of the first channel being maintained at the second signal level. 4. An accessory device according to any one of claims 1 to 3 , adapted to receive camera data over said third channel in response to transmission. The accessory control means, in response to stopping the transmission of the accessory data via the second channel when the signal level of the first channel is maintained at the second signal level, 5. An accessory device as claimed in any one of claims 1 to 4 , wherein the accessory device stops receiving camera data over the third channel. The accessory control means transmits the accessory data via the second and third channels as the communication performed in response to the signal level of the first channel being maintained at the second signal level. 6. An accessory device according to any one of claims 1 to 5 , wherein the accessory device transmits. The accessory control means adjusts the second and third signal levels in response to elapse of a predetermined time after the signal level of the first channel changes from the second signal level to the first signal level . 7. The accessory device according to any one of claims 1 to 6, wherein transmission of the accessory data through the channel is forcibly stopped. The accessory control means transmits information indicating a data size of the accessory data,
8. The accessory device according to any one of claims 1 to 7, wherein said accessory control means transmits said accessory data having a data size indicated by said information in said first mode. wherein the accessory control means transmits information indicating a data size of the accessory data in the second mode;
The accessory control means controls, in the second mode, the second channel and the 9. An accessory device according to any one of the preceding claims, wherein said communication with said imaging device is carried out via a third channel. 10. The accessory device according to claim 8, wherein the information indicating the data size of the accessory data indicates the number of frames to be transmitted as the data size. In the first mode, if transmission of accessory data having a data size indicated by the information has not been completed, the accessory control means increases the signal level of the first channel from the second signal level to the Stopping transmission of the accessory data in response to a change to a first signal level, and after stopping the transmission, the signal level of the first channel changes from the first signal level to the second signal level. 9. An accessory device as recited in claim 8, wherein said transmission is resumed in response to a request. The accessory control means, in the second mode, controls the second channel and the third channel in response to a change in the signal level of the first channel from the first signal level to the second signal level. 12. An accessory device according to any one of the preceding claims, wherein said communication with said imaging device is via a channel of . The accessory control means transmits information indicating a data size of the accessory data,
When the signal level of the first channel changes from the second signal level to the first signal level in a state in which transmission of accessory data of a certain frame is incomplete, the accessory control means controls the 2. After the frame transmission is completed, even if the data size of the transmitted accessory data is smaller than the data size indicated by the information, the transmission of the accessory data is stopped. 8. An accessory device according to any one of clauses 7 to 8. The accessory control means includes:
in response to maintaining the signal level of the first channel at the second signal level after the signal level of the first channel changes from the first signal level to the second signal level , the accessory data is transmitted over the second channel;
in response to maintaining the signal level of the first channel at the second signal level after the signal level of the first channel changes from the first signal level to the second signal level , wherein control is performed such that camera data transmitted from the imaging device in response to transmission of the accessory data via the second channel is received via the third channel. 2. The accessory device of claim 1. 15. An accessory device according to any preceding claim, wherein the accessory device is a lens device. An imaging device to which an accessory device is removably attached,
camera control means for controlling communication between the imaging device and the accessory device;
In the first mode, the camera control means causes the signal level of the first channel to change from the second signal level to the second signal level after the signal level of the first channel changes from the first signal level to the second signal level. responsive to being maintained at a level, communicating with the accessory device via a second channel and a third channel ;
The imaging apparatus , wherein the camera control means stops receiving accessory data in response to a change in the signal level of the first channel from the second signal level to the first signal level. . When the signal level of the first channel changes from the second signal level to the first signal level in a state in which reception of accessory data of a certain frame is incomplete , the camera control means controls the 17. The imaging device of claim 16 , wherein receiving of the accessory data is stopped after frame reception is completed. The camera control means receives the accessory data via the second channel and the 18. The imaging apparatus according to claim 16 , wherein camera data is transmitted through a third channel. The camera control means receives and receives the accessory data via the second channel as the communication performed in response to the signal level of the first channel being maintained at the second signal level. 19. The imaging apparatus according to any one of claims 16 to 18 , wherein camera data is transmitted through the third channel in response to reception. The camera control means, in response to stopping receiving the accessory data via the second channel when the signal level of the first channel is maintained at the second signal level, 20. An imaging device according to any one of claims 16 to 19 , characterized in that transmission of camera data via the third channel is stopped. The camera control means transmits the accessory data via the second and third channels as the communication performed in response to the signal level of the first channel being maintained at the second signal level. 21. The imaging device according to any one of claims 16 to 20 , which receives. After the signal level of the first channel changes from the second signal level to the first signal level , the camera control means adjusts the second and third 22. The imaging device according to any one of claims 16 to 21, wherein reception of the accessory data via the channel is forcibly stopped. The camera control means receives information indicating a data size of the accessory data,
23. The imaging apparatus according to any one of claims 16 to 22, wherein said camera control means receives said accessory data having a data size indicated by said information in said first mode. The camera control means receives information indicating a data size of the accessory data in the second mode,
The camera control means controls, in the second mode, the second channel and the 24. An imaging device as claimed in any one of claims 16 to 23, wherein said communication with said accessory device is performed via a third channel. 25. The imaging apparatus according to claim 23, wherein the information indicating the data size of the accessory data indicates the number of frames received as the data size. In the first mode, if reception of accessory data having a data size indicated by the information has not been completed, the camera control means increases the signal level of the first channel from the second signal level to the ceasing reception of the accessory data in response to a change to a first signal level, wherein the signal level of the first channel changes from the first signal level to the second signal level after ceasing reception; 24. The image pickup apparatus according to claim 23, wherein said reception is resumed in response to said operation. The camera control means, in the second mode, controls the second channel and the third channel according to a change in the signal level of the first channel from the first signal level to the second signal level. 27. An imaging device according to any one of claims 16 to 26, wherein said communication with said accessory device is carried out over a channel of . The camera control means receives information indicating a data size of the accessory data,
When the signal level of the first channel changes from the second signal level to the first signal level in a state in which reception of accessory data of a certain frame is incomplete, the camera control means controls the 17. After completion of frame reception, stopping reception of the accessory data even if the data size of the received accessory data is smaller than the data size indicated by the information. 23. The imaging device according to any one of 22. The camera control means
in response to maintaining the signal level of the first channel at the second signal level after the signal level of the first channel changes from the first signal level to the second signal level , the accessory data is received via the second channel;
in response to maintaining the signal level of the first channel at the second signal level after the signal level of the first channel changes from the first signal level to the second signal level 17. The apparatus according to claim 16, wherein the camera data transmitted in response to reception of the accessory data via the second channel is transmitted via the third channel. Imaging device. 30. An imaging device as claimed in any one of claims 16 to 29, wherein the accessory device is a lens device. A control method for controlling communication between an accessory device detachably attached to an imaging device and the imaging device, comprising:
In the first mode, after the signal level of the first channel changes from the first signal level to the second signal level, the signal level of the first channel is maintained at the second signal level. conducting said communication with said imaging device via a second channel and a third channel in response to
and ceasing transmission of accessory data in response to a change in the signal level of the first channel from the second signal level to the first signal level . In an imaging device to which an accessory device is detachably attached, a control method for controlling communication between the imaging device and the accessory device, comprising:
In the first mode, after the signal level of the first channel changes from the first signal level to the second signal level, the signal level of the first channel is maintained at the second signal level. conducting said communication with said accessory device over a second channel and a third channel in response to ;
and ceasing receiving accessory data in response to a change in the signal level of the first channel from the second signal level to the first signal level . In an accessory device detachably attached to an imaging device, a storage medium storing a program for causing a computer to execute a control method for controlling communication between the accessory device and the imaging device,
The control method is
In the first mode, after the signal level of the first channel changes from the first signal level to the second signal level, the signal level of the first channel is maintained at the second signal level. conducting said communication with said imaging device via a second channel and a third channel in response to
and ceasing transmission of accessory data in response to a change in the signal level of the first channel from the second signal level to the first signal level. Possible storage medium. A storage medium storing a program for causing a computer to execute a control method for controlling communication between the imaging device and the accessory device, in an imaging device to which an accessory device is detachably attached,
The control method is
In the first mode, after the signal level of the first channel changes from the first signal level to the second signal level, the signal level of the first channel is maintained at the second signal level. conducting said communication with said accessory device over a second channel and a third channel in response to ;
ceasing receiving accessory data in response to a change in the signal level of the first channel from the second signal level to the first signal level. Possible storage medium.

Images