JPS5948739A - Camera using microcomputer - Google Patents

Abstract

PURPOSE:To obtain a camera which operates at a low voltage, by using a microcomputer which has a stand-by mode and adding a simple sequence control circuit. CONSTITUTION:The microcomputer MPU1 enters an interruption sequence after a release switch SW3 is turned on, and outputs ASA speed information SU; and a DA converter 10 outputs an analog value, which is transmitted to a shutter control circuit 7 through an adding circuit. The control circuit 7 unlock a trailing curtain once a found shutter speed T is obtained. A source voltage Vcc starts dropping when a magnet 8 is powered on at the L-to-H point of time of a switch SW2. At this time, the MPU11 monitors an input terminal R7 and holds a stand-by signal R14 at L to enter stand-by operation. Consequently, no runaway occurs even when the source voltage drops below a normal microcomputer use voltage. Thus, the camera which operates at a low voltage is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera using a microcomputer.

Conventionally, several examples have been proposed as cameras using microcomputers (hereinafter referred to as MPUs).

For example, Japanese Patent Application Laid-Open No. 55-89823. In these cases, a microcontroller is used for all sequence control, which causes problems when the power supply voltage is low.

Camera power supply voltages can be roughly divided into 6V series (silver oxide battery, Ike 4SR44, or alkaline Tonike 4LR44) and 3V series (2 silver oxide batteries S R44, alkaline battery L).
There are two R44 or lithium batteries). Since the MPU has a complicated configuration, its operating voltage is inevitably higher than that of other ICs. Cameras that are powered by batteries are
"tty, the pressure is not constant, the release magnet °/t,
When current flows through the diaphragm control magnet and the shutter control magnet, a current flows, causing a sudden voltage drop. When an MPU is used, this voltage drop causes malfunction.

Conventional devices did not take measures to address this issue.

The present invention uses an MPU with standby mode,
By adding a simple sea case control circuit,
The purpose is to provide a camera that operates at low voltage.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows an embodiment of the present invention applied to a camera in instantaneous metering aperture front mode.

OP amplifier 11 1st diode 2. Log diode 3. and a reference voltage component 4 form a known photometric circuit.

5 is a memory circuit, mirror sketch SW when mirror up
2 is OFF and the photometry circuit output BV-A after narrowing down.
Remember V.

6 is an analog adder circuit, after mirror UP, DA converter 1
The apex value Sv of the film sensitivity and the output BV-AV of the memory circuit 5 are added as an output of 0. That is, (BV-AV) +SV='['V (1) 1°7 which outputs the apex value of the shutter speed is the shutter control circuit, which starts energizing the Nyanotamagnenoto 8 when the mirror SW turns from ON to OFF. 7. Trigger switch SW
After , turns from ON to OFF, timer capacitor C1
starts discharging, and after reaching a predetermined TV value, the shack magnet 8 is turned off.

9 is a sequential comparison comparator 1/-1 which outputs the photometric circuit 1 and D.
A comparison is made with the output of the A converter 10, the output is transmitted to the input terminal R6 of the microcomputer 11, and sequential comparison type AD conversion is performed.

10 is a DA converter and the output terminals R and -R8 of the microcomputer 11
From oooooo to 1 in binary by the output of 6 binoto
Generates 63-step analog beats up to 11111.

11 is M)) U, and in the example, Fujitsu 4-biy 1
- One-chip microcomputer MfH3851 is used. Connect the crystal or ceramic loss element 17 and the converter C21c3 to the Extal and Xtal terminals, and make (1 clock).

R1 to Ro are connected to the DA converter 10 as output 9W children, and control the DA converter 10.

1 (6 is input terminal 1hi 14 comparator 90
) input the output.

R7 is an input terminal to which a signal from the mirror switch SW2 is input.

R8-4, □ is an input terminal that switches film sensitivity information.
5-SW, input more.

R14 is a standby terminal S T B Y as an output terminal.
By connecting R14 to L during standby, it enters standby operation.

The standby operation function enables data retention with low power consumption, and when a standby signal is given, IVr
After executing the instruction currently being executed, the PU stops execution of the next instruction and enters standby operation while retaining the contents of each internal register. During standby operation, the MPU is completely stopped, so consumption and power consumption are reduced. Further, the 'i13: pressure required to maintain this state may be lower by about 0.5 [V] than the state in which the MPU is in motion. Therefore,
When using an electric power source as a power source, the power consumption increases, and the MP enters standby mode just before the voltage drops.
It can prevent U from running out of control. To cancel standby operation, reset the MPU or use the standby terminal STH
)'L→H.

iVI directly connected RI4 and ST13y,
This is because the standby mode cannot be entered by an internal command in [B885], and this is not necessary for things that can be processed by commands.

IIRQ is an interrupt input terminal, and the release switch 5W30
) Turn OFF → ON to enter the release sequence.

K3~i (0 is input only boat, input Kasuinochi 5W1
Receives aperture γf information f-fo from o-8W13.

0□ to Oo are output ports, and a display circuit is formed by resistors R+7 to R7o and light emitting diodes 27 to 2o. 8 bits, for example over 1000,500°250.1
25, 60, 30. Eight types of display such as 15-LT and 15-LT are possible.

RESET is a reset input terminal and when the power is turned on,
and receives a reset pulse when the mirror is down, lV
r Return the PU address to the start address.

12 is a comparator, which is compressed by resistors R7 and R2. . voltage dividing point, resistor R3 and Zener diode 13
A comparison is made with a reference voltage source by , and when the voltage is sufficient, it becomes L.

14 is an OR gate circuit, and mirror switch SW2 is L.
When the comparator 12 is L, it becomes L.

When the mirror is down and the battery is fully charged, it becomes ■.

15 is a one-shot multi-by-break, which receives the output of the OR gate circuit 14 at the falling trigger input terminal -TR,
A negative pulse is generated for a certain period of Jcl1. That is, a negative pulse is generated when the mirror is down or when the battery voltage exceeds a certain value.

Resistor R4 and capacitor C4 are power switch SW.

When turned on, R4, C, and 1 become equal to the time constant of 1/J1, and a reset pulse is generated.

Reference numeral 16 denotes an AND gate circuit which transmits a reset pulse when the power is turned on, a reset pulse when the mirror is down, and a reset pulse when the battery is restored to the reset input terminal RESET of the MPU 11.

Second (1) shows the sequence of the embodiment.

Explain the flow of the sequence.

``City'', 1ltx・``Sochi S Wn'／)＜O
When it becomes N, the negative pulse is generated by the resistor R4 and the capacitor C4, and the reset signal which is the output of the AND gate circuit 16 becomes L, and the MPUI is set to 1, and the command execution starts from -Start-Suzuya. Start.

OP amplifier 1 has a photometric output BLT-AUo during open metering.
occurs. BV is the apex value of the subject's brightness, and AV
o is the apex value of the lens's aperture, T T L
In the case of 1llll+light, it becomes BV AVn.

The microcomputer 11 sets 100000 to the R5-Ro terminal, and the DA converter successively transmits the analog quantity determined by 2'=32 to the comparison comparator 9.

If BV-AVo is more than 32, the output of comparator 9 becomes 1, the outputs of R1 to R, are 11.0000 cents, and when the output of comparator 9 is 0, R5 to l(.

is set to 010000. Well-known Ryoji]
It is a seven comparison type θ) AD conversion method. In this case, I have also proposed a development of these in Japanese Patent Application Laid-Open No. 57-54822, and the details are omitted.

Therefore, MPU II uses BV-AVo as brightness information.
can be entered. Also person Kasuinochi S~V,~
9, ASA sensitivity information is input from input terminals 1 and 12. 5 Sui, Chiniori 32 ways ASA6
~ 1/3 up to 8000 [T: You can get 6 lights with the Vl Snap knob.

Next, input Kasuinochi SW'+ o -SW'+ s
Accordingly, the aperture/information AV-AVo is inputted from the input outside child Kc, ~. 16 ways with 4 switches, 1
/2 [T! :■] Up to 8th dan in steps: Able to master the technique.

AV is the apex value of the aperture value, and AV AVo is the apex value of the number of steps to stop down from wide open.

With the above input, MPUI 1 performs the following calculation, (RV-Avo)-(AV-AVn') +SV:BV
-1-8V-AVEETV (2) The controlled shutter speed can be determined.

When the shutter speed is 1/125, the display output O1~Oo
is 11110111, and 0. If only the light is set to L, the light emitting diode 23 is energized and the part 125 lights up.

When the release switch SWs is turned on, the output of the 6Ij1 optical circuit 1 is narrowed down mechanically, and the BV-A
It becomes V.

Mirror switch SW2 is turned OFF just before mirror up.
Then, the memory circuit 5 stores the photometric output BV-AV.

After turning on the release switch SW3, the MPU 11 enters an interrupt sequence and sets the ASA sensitivity information SU to R6 to Ro.
Output from the MiiA child and cause the DAi converter]0 to output an analog amount according to S■. The adder circuit 6 performs the calculation of equation (1) and transmits the TV value to be controlled to the shutter control circuit 7.

In the shutter control circuit 7, the mirror switch sw2 is ON-
> Start energizing the shutter magnet 8 from OFF, and
When the mechanical weight is replaced and the shutter 111ffT, which is determined after the tricycle switch SW1 is turned off, is reached, the shutter net 8 is de-energized and the rear curtain holder 112 is removed.

When mirror switch SW2 or f is ->H, power supply voltage ■ starts from the start of energization of magnet 8 from +'sj. C begins to fall.

At this time, the MPUII monitors the input terminal R7, sets the standby signal R14 to L when the mirror switch SW2 is at L-+H, and sets the standby terminal S〒BY to L, thereby entering the standby 1Ij1 operation. For this reason,
Even if the power supply voltage vcc falls below the pen pressure normally used by a microcomputer, runaway will not occur because the power supply voltage is guaranteed to be even lower during standby ('6).

After the mirror is down, if the panteri is sufficient, the output of the OR gate circuit 14 changes from H to L, the one-shot multivibrator 15 emits a negative reset pulse, which crosses the AND gate circuit 16, and the reset signal becomes L and the MPUI
]Reset.

This operation cancels the standby operation, R1 becomes H, the MPU address becomes the start address, and the photometry display sequence described above begins.

If the internal resistance of the battery becomes high and recovery of the power supply voltage is delayed, the output of the comparator 12 will change from H to H after mirror down.
At the time point L, the one-shot multi-by-break 15 issues a reset pulse and resets M l''[J ].

This is because the power supply voltage needs to be restored to cancel the standby operation.

In the embodiment, there is no problem in entering standby operation because the mirror switch SW2 operates quickly from L → [(MPUI) compared to the voltage drop. Until this point, the release switch After 5W3H->L, the microcomputer can perform various operations. Figure 3 is a block diagram 1 of the second embodiment 71 (example) according to the present invention. Only a few additions have been made to the case of Figure 1. .

31 is a speedlight control circuit in which 'tM and tll'A are the same.

32 is a charging control circuit, which outputs the rapid charging signal to the AND gate circuit 33 and the speedlight control circuit 31. Full 1. b: Power supply '1' inside (when the pressure drops, it will turn off)
1. The output of the circuit 33 becomes ■], and the IV [PU] 1 detects the input signal 1 and 3 and enters standby egg production.

Figure 4 is block 1 of the third embodiment of the great invention. The first embodiment resets the standby operation.
In contrast to this, the cancellation is performed by setting the -ta fby signal to L (to H).

The NOR gate 41 becomes [■] when the mirror switch SW2 is [■ or the comparator 12 is H]. In other words, the fortune-telling L is during Mira-up or when the battery is below a predetermined value. The output of the orate 42 is I (the output of 14 becomes L, - is lucky during the period of the record, standby + til).

FIG. 5 is a block diagram of the embodiment of FIG. 4 of the invention.

51 is a motor drive drive circuit whose power source is the same as that of the camera body. Winding is in the middle, winding switch SW. becomes L-TI, controls the motor drive, drive circuit 5], and rotates the motor.

When the power source or pressure decreases while the motor is being hoisted,
The output of the AND gate circuit 52 becomes H, and the MPU 11 then enters standby operation. Once the voltage has been restored, the MPU II resumes operation with a reset pulse generated at the same time as the one-shot multi-by-break 15. References include the Fujitsu 4-bit one-chip microcomputer MB8850 series user's manual.

As described above, according to the present invention, the functions of the microcomputer can be combined with the sequence of the camera to make maximum use of its capabilities. During standby, the voltage of the microcomputer is raised and almost no current is applied to the microcomputer itself, which has the effect of reducing the load on the battery by 1'.

In the example, the CEND command (MB885 manufactured by Fujitsu) was used, but the CEND command (5M-5 manufactured by Yab
Stop the clock such as series) or E (A L'
f" command sleeve command etc. have a similar effect of 1 (11
Specially possible.

[Brief explanation of the drawing]

Figure hJ1 is a block diagram of an embodiment of a camera according to the invention. Figure 2 is the sequence diagram. Figure 31 is a block diagram of a second embodiment of the present invention. FIG. 4 is a block diagram of a third embodiment of the present invention. FIG. 5 is a block diagram of a fourth embodiment according to the present invention. Patent applicant: Takashi Watanabe, agent of Nippon Kogaku Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A camera that uses a microcomputer and is characterized by a standby operation when the load on the "sequence" dual source increases.