JPS5810727A - Pulse counting method for camera - Google Patents

Abstract

PURPOSE:To make it possible to count accurately high-speed clock pulses and control pulses, by counting oscillated pulses in a timer interruption generating circuit forming a program timer. CONSTITUTION:When a switch 1 is switched to the side of a contact (b), external oscillated clocks are applied to a timer interruption generating circuit 17, which forms a program timer, through a frequency divider 16 of a one-touch microprocessor 10, and the circuit 17 counts these pulses. When the counted value reaches a value set through a CPV11, the circuit 17 generates a signal for clock or control. By this constitution where pulses are counted independently of the CPV, high-speed clock pulses and control pulses for a stop or the like are counted accurately with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of counting time measurement pulses or control pulses using a microprocessor mounted on a camera.

Conventionally, cameras have counted the pulses generated in relation to the aperture amount, film feed amount, etc., and when the counted value reaches a set value, a specific operation is performed to control the aperture or film feed. Control of transmission, etc. is performed automatically. in this case,
Circuits such as pulse counting and control parts are implemented using ordinary digital ICs.
If it is configured with 9, it becomes a real device l! Not only does F& become worse, but power consumption also increases.
Microprocessor, especially oscillator, RAM% ROM,
The use of a one-chip microcontroller with a built-in I10 board, timer interrupt generation circuit, etc. is being considered. Since it is designed for mounting a camera, a low-power microprocessor is desired. As a response to this demand, C
- Powers MOa's one-chip microprocessor. However, since the conventional microprocessor operates at a low frequency fundamental clock such as 100KH, control based on the program program causes problems as described below. That is, in determining whether the count value has reached the set value, the microphone processor subtracts 1" from the count value (set value) written in the counter RAM every time a pulse is generated, and the value is determined as "9". O"
This is to determine whether or not it has become. In this case, the subtraction program basically proceeds by vxt9, and depending on the instruction system, the time is 20 to 4 times the clock, that is, 00 μs @ e (t, jKHz). Requires execution time. On the other hand, the above-mentioned counting pulse has a frequency of λ to KHz in order to control the camera elements at high speed and with high precision. Therefore, in counting by the subtraction program, even if a pulse arrives, it is missed during execution of the subtraction program, so there is a problem that accurate pulse stitch number and control cannot be guaranteed.

The present invention has been made in consideration of these points, and its purpose is to generate pulses with a frequency close to or higher than the basic frequency of the microprocessor by skillfully utilizing the timer interrupt generation circuit of the microprocessor. The purpose of the present invention is to provide a camera pulse counting method that can count pulses with high precision.

Hereinafter, the present invention 111 will be explained in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of the pulse counting method of the present invention. In the same figure, l is a switch, and IO is a low-power type, for example, C-
It is an MO8 type one-chip microphone four processor.

This one-chip microprocessor io is CPU//
%RAM/K, ROM/J, oscillation circuit (CK)/
#, input/output boat (X10 boat)/j, frequency divider (
DIV) #.

It consists of a program timer (PT) t7. CPU// is connected to RAM/Co, RO via bus/l.
M/J%I10 Port is% Can exchange signals with P'I'/7, execute various programs stored in ROM/J, write and read data to/from RAM/! The 0 oscillation circuit /l, which can send and receive signals to and from an external device through the 10 port /j'1, and set setting values to PT/7, is connected to the CPU// by externally attaching a crystal oscillator lμ&. It generates the basic clock given to the Incidentally, when the clock precision [1-6 to 9] is not a problem, a capacitor or a resistor can be used in place of the crystal resonator l≠1. PT/7 is a timer interrupt generation circuit that generates a timer interrupt signal when the number of pulses input via DIV#l reaches a set value. This setting value is set as cpυ/l via the path /I, and the timer interrupt signal is sent directly to the CPU without going through the bus ltt.
// is supplied. This PT/7 is
Normally, the interrupt signal 'f' is generated by using the clock from CK/44 via DIV#t, but in the present invention, the clock selected by the switch l is sent to DIV/4. It is configured to give either one type of pulse (clock) or control pulse. In such a configuration, the external connection of CK/≠ is the oscillation t64.
If 1-00H1, DIV/4 is divided by 1 and the PT/7ftl bit configuration is used, when the switch /f is set to the a side, the range in which PT/7 can be measured is 5 houses...~/ ,
21 rm-... When set to 1, conversely, when switch 7thg4 is set, pulses can be counted completely independent of CPU// operation, resulting in a maximum of 274 FT/70 Kaparnuca pulses.

What is the maximum number of pulses that can be given to the input terminal of DIV/A? l co
It is possible to count the number of pulses in the even scan.

FIG. 1 is an explanatory diagram of nine cases in which the present invention is applied to aperture control of a camera. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. 1 is a disk-shaped Siemens star that is connected to the aperture mechanism of the camera and rotates in response to the aperture tightening operation, and has a large number of slits/a formed radially at a constant pitch. The amount of rotation of this slit co/a for l pitch is 0. /MVK compatible. An infrared light emitting diode (here) and a photodiode (J) are placed opposite to each other with this Siemens star column (1) in between. Also, a resistor 4c is connected to the anode of the photodiode J.
A voltage of 10 V is applied through 'lt. By rotating the Siemens star 27 and intermittent infrared beams from the two light emitting diodes, a pulse signal is obtained from the anode of the photodiode 2J. This signal is applied to one AND gate λ of the switching means 1.

An external oscillation clock signal of CK/≠ is applied to the input terminal of the other AND gate controller 7. On the other hand, the signal (selection signal) from the output port of the microprocessor 10 is given to the gate core directly and to the gate core via an inverter 21f, so that a complementary inhibition signal is applied to the gate core and the core. is being applied. ORGATE KOTA uses the output of the gate core and core as human power and feeds the output to the frequency divider.

In such a configuration, the operation will be explained by taking as an example the case where aperture control is performed. Incidentally, a flowchart of this operation is shown in FIG.

In this case, a task loop flag is set in the control task in CI'U//. The task loop flag is a flag that specifies whether a program timer should be used to measure time or a control program should be executed at the time of a timer interrupt, and should be set using the RAMK/bit. When it is desired to execute a control program at the time of a timer interrupt, the CPU// sets this flag as described above, then sets the selection signal t to Low and opens the gate λ.
After that, set the value (9 values converted to the number of pulses) that you want to narrow down to PT/7. This completes the preparation for counting control pulses. Before the photographing sequence, the diaphragm is in an open state due to the aperture stop pin for wide-open metering, but as the photographing sequence begins, the stop pin is released and the restoring force of the spring starts to stop the aperture. Correspondingly, the Siemenster J/ rotates, and the photodiode auto 3 generates a pulse signal. Since the selection signal is low, this pulse signal passes through the ant gate 1 and the or ate gate and enters DIV/4. The amount of division of DIM/A is determined at the manufacturing stage, but here it is assumed that there is no division, that is, the input signal is output as is. Also, the aperture is narrowed down by / KV from the open value. It is assumed that "10" is set as a setting value for 7. Therefore, in this case, PT/'I generates a timer interrupt signal when the output pulse t10 of the photodiode controller 3 is received at 9. Note that until the CPU // receives an interrupt signal, when an interrupt occurs or when a 0 timer interrupt occurs while another program is being executed, the CPU // moves to execution of the control program. A magnet installed in the mechanism that stops the narrowing is activated, which activates a stop pin to stop the narrowing operation.

In this way, the aperture ring can be stopped at a position where the aperture is stopped down by /mV from the open value. Thereafter, the CPU // completes the task loop 7 lag t-IJ upper setting and aperture 9 control operations, and decodes to the original state l11 (execution of the main program, etc.). By resetting the task loop flag, the program executed at the timer interrupt is a normal timekeeping program. That is, when an interrupt occurs in this state, the CPU // confirms with the task loop flag that it is a task for p time measurement, and executes the time measurement program. However, the present invention is not limited to the present invention, and other switching means such as electronic switches and relays may be used.

FIG. 3 shows a configuration in which a plurality of time measurement pulses and control pulses are appropriately switched and selected to perform a wide variety of controls. 1 is a generator that generates pulses (clocks) with different periods for time measurement, 321 to 3 are pulse generators that generate pulses in relation to each camera element, and 3J is the output of these generators. This is a switch that selectively selects the desired pulse power. By combining this with the set value of PT/7, a wide variety of controls can be performed.

As explained above, the present invention counts pulses using a timer interrupt generation circuit (program timer). Therefore, according to the present invention, high-speed operation is possible without being restricted by the operating speed of a microprocessor. Hour hand pulse (
By accurately counting clocks) and control pulses,
k% and various pulses can be alternatively selected by simple switching means to perform a wide variety of pulse counts, making it possible to accurately control the camera element. Note that the present invention includes:
CPU, RAM, ROM, i'T, etc.? Consists of nine chip microbes, not only 7 microbes, but also D
IM, FT, RAM, ROM.

It is also possible to use a microprocessor consisting of a co-chip or a J-chip with any components such as I10 baud), CK, etc. or any combination of components on separate chips.

[Brief explanation of drawings]

FIG. 3 is an explanatory diagram of the present invention that enables a wide variety of controls. /, 37...Switch no 0...One-chip microprocessor //...C
PU # Frequency divider 17...Program timer (timer interrupt generation circuit) Patent applicant Roku Konishi Photo Industry Co., Ltd. Agent 9 Pj1 Toji Shii Toji 1 Figure n 2 Figure 1 (Encounter 1 Mata I^ No. Figure 3]

Claims (1)

[Claims] Using a micro processor with a timer interrupt generation circuit capable of counting clocks, seven pulse inputs are selectively input from one or more hour hand pulse inputs and one or more control pulse inputs. Select and lead to the input terminal of the timer interrupt generation circuit to calculate the number of pulses of the pulse.