JPH0474692B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a data transfer device for transmitting various data of an interchangeable lens to a camera in an interchangeable lens camera system. [Prior Art] Conventionally, a ROM that fixedly stores various data of the interchangeable lens is provided in the interchangeable lens, and the address of the ROM is specified based on the address data output from the camera body, and the data read from the ROM is read out. A device that transmits data in series to a camera has been proposed (see Japanese Patent Laid-Open No. 108628/1983). In the conventional device described above, in order to specify the ROM address, it is necessary to provide an address data output circuit on the camera body side, as well as a clock signal terminal to exchange signals between the camera body and the interchangeable lens. , address data terminals, output data terminals, power supply terminals, and other terminals are required. In order to perform such signal transmission with a small number of terminals, a clock pulse is sent from the data collection side to the terminal side, and the terminal side counts these clock pulses and uses them as a signal to specify a memory address, and synchronizes the read data with the clock pulse. A data transmission device is known that sequentially outputs one bit at a time (see Japanese Patent Laid-Open No. 72738/1983). [Problem to be solved by the invention] In a camera system that uses an interchangeable lens equipped with a ROM that stores lens-specific characteristic data, it is difficult to determine the type of interchangeable lens (fixed focal length lens, variable focal length lens, etc.), The number of data to be transferred from the lens side to the camera body side differs depending on the mode of use. Conventionally proposed data transmission devices of this type do not take into account the number of data to be transferred, and are configured to read a predetermined number of data. Therefore, even if the number of data to be transferred from the lens side to the camera body side is different,
The configuration is such that data transfer operations for all lenses are performed in accordance with the interchangeable lens that has the largest amount of data. However, with such a configuration, unnecessary data transfer operations may be repeated depending on the type of lens, etc., so the efficiency of transferring only valid data may be reduced depending on the type of lens etc. A data transfer device is desired. This can be accomplished by obtaining information regarding the type of interchangeable lens, etc. before starting the data transfer operation. However, since information regarding the type of interchangeable lens is one of the characteristic data unique to the lens and is stored in the ROM, only after the characteristic data indicating the type of lens, etc. is transferred from the lens side to the camera body side. It is possible to determine the type of lens, etc., but it is not possible to determine the type of lens, etc. before data transfer. It is an object of the present invention to solve the above problems and provide an efficient data transfer device that can handle different amounts of data depending on the type of lens, etc. [Means for Solving the Problems] The present invention solves the above problems, and provides a camera that outputs camera shooting information in an interchangeable lens camera system in which a plurality of lens characteristic data are transferred from an interchangeable lens to a camera body. A data output means, a signal output terminal that outputs a signal commanding data readout of the interchangeable lens, a clock terminal that outputs a clock signal for synchronizing data readout, and inputs lens characteristic data input in series from the interchangeable lens. and a camera data input terminal for inputting the camera data output from the camera data output means, and a microcomputer for performing predetermined calculations based on the lens characteristic data and the camera data. , a lens characteristic data holding means that holds a plurality of lens characteristic data, and a read command signal that starts the operation, counts the clock signals input to the clock signal input terminal, and counts the same number of clock signals as the number of bits of the lens characteristic data. a first counter that outputs a carry signal when a signal is input; a second counter that starts operating in response to a read command signal and counts the carry signal output from the first counter;
data specifying means for sequentially specifying a plurality of lens characteristic data in the lens characteristic data holding means based on the output signal of the second counter; The interchangeable lens is equipped with a lens data output means for outputting to the camera body side, and the microcomputer includes a clock signal generation means for temporarily stopping the output of the clock signal every time a clock signal of the same number as the number of bits of the lens characteristic data is generated. and a shift register that reads data input to the serial input terminal one bit at a time in synchronization with the clock signal output from the clock signal generating means.
Instructs reading of lens characteristic data, and
A control means for controlling the lens characteristic data reading operation by determining whether to continue or terminate the subsequent lens characteristic data reading operation based on the input lens characteristic data while the clock signal is paused. It is characterized by having The control means configured in the microcomputer controls the reading operation of the lens characteristic data by determining whether to continue or terminate reading of subsequent lens characteristic data based on the lens characteristic data indicating the type of lens. You can do it like this. [Function] When data is read from the lens side to the camera body side in synchronization with a clock signal, one unit of data is read by generating the same number of clock signals as the number of data bits, and then the clock signal is read. Pause generation to interrupt data loading. Then, during the suspension period, the read lens characteristic data (characteristic data indicating the type of interchangeable lens, etc.) is determined, and from that lens characteristic data,
If it is determined that there is more data to be read after that, the generation of the clock signal is restarted and the data reading operation is controlled to continue. Embodiment FIG. 1 is a block diagram showing a system of an interchangeable lens type camera to which the present invention is applied, in which the LEC on the right side from the dashed-dotted line is the lens side circuit, and the remaining circuits are the camera side circuits. BA is the camera's power battery,
MAS is a manually closed power switch. When this power switch MAS is closed, power is supplied from the power line +E to a microcomputer (hereinafter referred to as microcomputer) MCO and an oscillator OSC. Further, when the power switch MAS is closed, the power-on reset circuit _POR1 is activated, and a reset signal is sent from the terminal _PO1 to the reset terminal RE of the microcomputer MCO, so that the microcomputer MCO performs a reset operation. Also, the clock pulse from the oscillator OSC is applied to the clock terminal CL of the microcomputer MCO.
sent to. Furthermore, this clock pulse is also supplied to the exposure time control circuit TIC, the aperture control circuit APC, the release circuit RLC, and the mirror release circuit MRC. LMS is a photometric switch that is closed by the first step of pressing the release button (not shown). When this switch LMS is closed, the output of inverter IN ₅₀ becomes "High" and the input terminal of microcomputer MCO is
This “High” signal is transmitted to _i1 . When the input terminal i ₁ becomes "High", the microcomputer MCO sets the output terminal O ₁ "High", makes the output of the inverter IN ₅₂ "LOW", makes the transistor BT ₅₀ conductive, and connects the power line +V to the camera side. oscillator
Power is supplied to the circuits excluding the OSC and microcontroller MCO, and the power line +V _F is connected to the circuit LEC on the interchangeable lens side via the buffer BF and terminals JB ₁ and JL ₁ .
Power is supplied via the Transistor BT ₅₀ conducts and the power line +V
Power-on reset circuit starts when power is supplied from
Exposure time control circuit from terminal PO ₂ when POR ₂ operates
TIC, aperture control circuit APC, release circuit RLC,
A reset pulse is sent to the mirror release circuit MRC to reset these circuits. LMC is a photometry circuit, and this photometry output (analog) Bv-Avo (Bv: subject brightness, Avo: open aperture value) is input to the analog input terminal ANI for A-D conversion of the microcomputer MCO. Furthermore, the input terminal REV of the microcomputer MCO is a reference potential input terminal for the D-A converter provided in the microcomputer MCO, and this terminal has a photometric circuit LMC.
A reference potential from a constant voltage source provided inside is input. TIS is a device that outputs the data of the set exposure time, and this set exposure time data is transmitted to the microcontroller.
Input to input port IP ₁ of MCO. APS is a device that outputs data on the set aperture value, and this set aperture value data is input to input port IP ₂ of the microcomputer MCO. FSS is a device that outputs the data of the set film sensitivity, and this set film sensitivity data is input to the input port of the microcontroller MCO.
It is input to IP ₃ . The MDS is a device that outputs data corresponding to the set exposure calculation mode, and the data from this device is input to the input port IP ₄ of the microcomputer MCO. The DSP is a display circuit that displays exposure control values, etc., and the display contents are controlled by the common terminal COM and segment terminal SEG from the microcomputer MCO. The output terminal O ₃ of the microcomputer MCO is connected to the reset terminal RE of the counters CO ₅₀ and CO ₅₂ on the lens side via terminals JB ₃ and JL ₃ . This output terminal _O3 becomes "High" while reading data from the interchangeable lens, and the reset state of the counters _CO50 and _CO52 is released. The terminal SIC of the microcomputer MCO is the terminal
This is a terminal that outputs a clock pulse for synchronization when reading data serially to SID, and SID is a serial input terminal for reading data that is serially input as described above. The terminal SIC is connected to the clock input terminal CL of the counter CO ₅₀ via the terminals JB ₂ and JL ₂ , and the terminal SID is connected to the terminals JL ₅ and CL.
The output terminal of OR circuit OR ₅₀ is connected via JB ₅ . FIG. 2 shows a circuit example of a serial data reading section provided in the microcomputer MCO related to the terminals SIC and SID mentioned above. FIG. 3 is a time chart showing the operation of the circuit shown in FIG. 2. In Figure 2, serial data read command SIIN (Figure 3
SIIN), the flip-flop FF ₅₀ is set (FF ₅₀ Q in Figure 3), and the clock pulse of the oscillator OSC is sent from the AND circuit AN ₇₀ to the microcomputer.
The clock pulse DIC frequency-divided within the MCO is connected to the terminal SIC.
At the same time, the clock pulse from the AND circuit AN ₇₀ is input to the clock terminal CL of the 3-bit binary counter CO ₆₀ and the 8-bit shift register SR ₅₀ .
The shift register SR ₅₀ is connected to the clock terminal CL.
At each falling edge of the clock, data is fetched from the terminal SID. Then, when the 8th clock pulse rises, the carry terminal CY of counter CO ₆₀ becomes “High”.
(CY in Figure 3), and when the 8th clock pulse falls, the output of the AND circuit _AN72 rises to "High" ( _AN72 in Figure 3). This results in flip-flop FF ₅₀ and counter CO _60.
is reset (Fig. 3 FF ₅₀ , CY), and furthermore,
The serial data input flag SIFL is set to "High" (FIG. 3, SIFL) and the operation is completed. Returning to FIG. 1 again, the switch RLS is a release switch that is closed in the second step of pressing down the release button, and the switch EXS is a release switch that is closed when the operation of the exposure control mechanism (not shown) is completed.
Preparing the exposure control mechanism for exposure control operation (charge)
This is a switch that is released when the process is completed. When the charge of the exposure control mechanism is completed and the switch EXS is opened and the release switch RLS is closed with the output of the inverter IN ₅₆ in the "Low" state, the output of the AND circuit AN ₆₀ becomes "High". The output of this AND circuit AN ₆₀ is connected to the interrupt terminal it of the microcomputer MCO, and the microcomputer MCO
When it rises to "High", the microcomputer MCO starts the exposure control operation no matter what operation it is performing. On the other hand, if the charge of the exposure control mechanism is not completed and the switch EXS is closed and the output of the inverter _IN56 is "High", even if the release switch RLS is closed, the AND circuit will not be activated.
The output of AN ₆₀ never becomes “High” and the microcomputer MCO does not perform any operation for exposure control. The output port OP ₁ of the microcomputer MCO outputs the exposure time data Tv to the exposure time control circuit TIC, the output port OP ₂ outputs the aperture stage number data Av-Avo to the aperture control circuit APC, and the output terminal O ₂ outputs the release circuit RLS. The output terminal _O4 outputs a pulse to start the exposure control operation to the mirror release circuit MRC. In addition, input ports IP ₁ to IP ₄ and output ports OP ₁ and OP ₂ of the microcomputer MCO are replaced with a common data bus, and the microcomputer MCO and data input/output part TIS,
Data may be exchanged with APS, FSS, MDS, TIC, and APC on a time-sharing basis. Next, in the circuit LEC on the lens side, the counters CO ₅₀ and CO ₅₂ are each 3-bit binary counters, and the counter CO ₅₀ counts the rising edge of the clock pulse from the terminal SIC.
CO ₅₂ counts the falling edge of the carry terminal CY of counter CO ₅₀ . The 3-bit outputs h ₂ , h ₁ , h ₀ of the counter CO ₅₀ are input to the decoder DE ₅₀ ,
This decoder DE ₅₀ outputs the signals shown in Table 1 in response to the data from the counter CO ₅₀ .

[Table] The 3-bit output h ₅ , h ₄ , h ₃ of the counter CO ₅₂ is input to the decoder DE ₅₂ , and the decoder DE ₅₂ outputs the signals shown in Table 2 in accordance with the data from the counter CO ₅₂ .

[Table] Among the outputs of decoder DE ₅₂ , terminal g ₃ is connected to select terminal SE of data selector MP ₅₀ , and data selector MP ₅₀ has terminal g ₃ set to “Low”.
When , the input data from input section γ ₁ is “High”
When , input data from input section γ ₂ is transferred to ROM
Output as (RO ₅₀ ) address data. The upper 5 bits of the input section γ ₁ are connected to ground, and the lower 3 bits are connected to the output terminals g ₂ , g ₁ , g ₀ of the decoder DE ₅₂ . Therefore, as for the address of the ROM (RO ₅₀ ), "00000000" to "00000100" are sequentially designated while the output of the counter CO ₅₂ is "000" to "100". The input section γ ₂ has a decoder DE ₅₂ for the upper 3 bits.
The output terminals g ₂ , g ₁ , and g ₀ are connected, and the lower 5 bits are input with data from the code plate COD linked to the focal length setting member (not shown) of the zoom lens. Therefore, the address of the ROM (RO ₅₀ ) is specified as "001φφφφφ" to "011φφφφφ" while the output of the counter CO ₅₂ is between "101" and "111". This indicates that φ may be either 0 or 1. Next, the data stored in each address of the ROM (RO ₅₀ ) will be explained with reference to Table 3.

【table】

【table】

Claims (1)

[Claims] 1. In an interchangeable lens camera system in which a plurality of lens characteristic data are transferred from an interchangeable lens to a camera body, there is provided a camera data output means for outputting photographing information of the camera and a command for reading data of the interchangeable lens. A signal output terminal that outputs a signal, a clock terminal that outputs a clock signal for synchronizing data readout, a serial input terminal that inputs lens characteristic data input in series from an interchangeable lens, and output from the camera data output means. The camera body has a microcomputer that performs predetermined calculations based on the lens characteristic data and camera data, and the camera body has a camera data input terminal for inputting camera data to be input, and the camera body is equipped with a microcomputer that performs predetermined calculations based on the lens characteristic data and camera data. a holding means, and a first circuit which starts its operation in response to a read command signal, counts clock signals input to a clock signal input terminal, and outputs a carry signal when the same number of clock signals as the number of bits of lens characteristic data are input. a counter; a second counter that starts operating in response to a read command signal and counts the carry signal output from the first counter; data specifying means for sequentially specifying the specified lens characteristic data based on the clock signal;
The interchangeable lens is equipped with lens data output means that outputs the lens data bit by bit to the camera body side, and the microcomputer is configured to generate a clock signal that temporarily stops outputting the clock signal every time the same number of clock signals as the number of bits of the lens characteristic data is generated. a shift register that reads data input to the serial input terminal one bit at a time in synchronization with the clock signal output from the clock signal generation means; control means for controlling the lens characteristic data reading operation by determining whether to continue or terminate subsequent lens characteristic data reading operations based on the lens characteristic data obtained during a pause of the clock signal; A data transfer device for an interchangeable lens camera system. 2. In the data transfer device for an interchangeable lens camera system according to claim 1, the control means within the microcomputer continues reading subsequent lens characteristic data based on lens characteristic data indicating the type of lens. A data transfer device for an interchangeable lens camera system, characterized in that it determines whether to start or end.