JP2506347B2 - E ↑ 2 ▼ PROM built-in camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention is a camera and to perform control by the microcomputer, in particular a built-in E ² PROM, E ² PROM which the data related to the camera and to write to the E ² PROM It concerns a built-in camera.

[Prior Art] In recent years, various cameras equipped with a microcomputer, in which focus adjustment and exposure amount control are performed by the microcomputer, are commercially available.

In that case, normal shooting information is stored in the RAM of the microcomputer, but since the memory of the RAM is erased when the power is turned off, shooting information such as the total number of releases cannot be stored.

Of course, a backup power source may be provided for the RAM to retain the memory, but in that case, it is necessary to equip a backup battery, and it is necessary to provide a space for that, which increases cost. Become. In this regard, electrically clearing, but writable E ² PROM is advantageous because the backup power supply is unnecessary, E ² PROM currently provided on the market, there is a limit to the number of rewriting, E ² PROM
There is a problem to be solved in adopting and controlling it.

In Japanese Patent Laid-Open No. 60-61731, an E ² PROM is built in, and shooting information such as the number of films and data indicating a winding switch state are stored in the E ² PRO when the power supply battery is removed or the voltage drops.
A camera has been proposed in which data is written in M and the written data is read when a battery is attached. However, in the above-mentioned camera, all data is written uniformly, and writing according to the content of each data is not performed.

[Object of the Invention] A basic object of the present invention is to provide an E ² PROM built-in camera capable of rewriting according to the content of data to be written. More specifically, it captures the film sensitivity, which is important information for shooting but often forgets its setting, and writes the film sensitivity to E ² PROM only when the film sensitivity needs to be rewritten. It aims to provide a camera with built-in E ² PROM.

[Configuration of the Invention] To achieve the above object, E ² PROM built-in camera according to the present invention, with a built-in control microcomputer, E ² PROM which writing and erasing are electrically controlled by the control microcomputer With built-in E ² PR
The OM has a memory area for storing at least film sensitivity. On the other hand, the mode setting means for setting the film sensitivity changing mode, the film sensitivity setting means for setting the film sensitivity to be changed by a predetermined external operation when the film sensitivity changing mode is set, and the set film sensitivity Rewriting determination means for determining whether or not rewriting of the E ² PROM film sensitivity memory is necessary,
When the rewriting determination means determines that rewriting is necessary, in response to the release of the film sensitivity changing mode, the film sensitivity set by the film sensitivity setting means is written in the film sensitivity memory area of the E ² PROM. And means for controlling the writing of the film speed to the E ² PROM.

In the present invention, when the film sensitivity is set in the film sensitivity changing mode, it is judged whether or not the set film sensitivity is to be written in the E ² PROM, and if it is judged that the film sensitivity should be written, the film sensitivity change is made. When the mode is released,
Write the film sensitivity set in E ² PROM.

EXAMPLES Examples of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a circuit block diagram of an embodiment for achieving the present invention.

(E) is a battery that supplies power to each circuit, (μC) is
A microcomputer that controls the entire camera (hereafter referred to as a microcomputer). The flow chart of the microcomputer (μC) that controls the entire camera will be described later. (E ² PR
OM) is a ROM that is electrically writable and erasable. It has a built-in booster circuit. When a write signal is input, it is automatically erased and the voltage required for writing is boosted. Then, it becomes possible to write to the ROM. (LMC) is a photometric circuit that measures the brightness of the subject.
A digital signal represented by an apex system is output to the microcomputer (μC) as brightness information. (LEC) is a lens circuit that outputs the open aperture value (not shown) peculiar to the interchangeable lens to the microcomputer (μC) as a digital signal indicated by an apex system, and (AEC) is based on the exposure information from the microcomputer (μC). The exposure control circuit for controlling the diaphragm and the focal plane shutter, (MOD) is a one-frame winding circuit for controlling the motor to wind one frame of the film,
(ISO) automatically reads the film sensitivity when a film (hereinafter referred to as DX film) in which film information such as film sensitivity and the number of films is encoded and printed on the film container is used. While outputting the digital signal indicated by to the microcomputer (μC),
This is a film sensitivity reading circuit that automatically reads the number of films of the film and outputs it to the microcomputer (μC).
(DISP) is a display device that performs various displays based on the signal output from the microcomputer (μC), and (BC) detects the battery voltage to prevent camera malfunctions when the voltage drops below a predetermined voltage. When this battery check signal is input to the microcomputer (μC) in the battery check circuit that stops the control of the camera, the microcomputer (μC) executes the flow of the interrupt routine BATINT described later. (DC-DC) is
When battery voltage drops, microcomputer (μC) and E ² PR
This is a converter circuit that supplies a stable 5V power to the OM.

Next, explaining the signal lines of the microcomputer ([mu] C) and E ² PROM, and the microcomputer ([mu] C) and E ² PROM, the E ² PROM RO
Address bus for specifying M address (AD ₀ ~ ₇ ) Data bus (O ₀ ~ ₇ ) for transmitting / receiving data, W / R control line (/ R) for transmitting read / write signals, read, Chip enable line (CE) that transmits a signal to start writing control, Wr that transmits a Write Busy signal indicating that writing is in progress
The devices are connected by the it Busy line (W · Bu), and each device is provided with the terminals required for it. (Trl) is
Microcomputer (μC) E ² PROM, power supply transistor that supplies power to devices other than display device (DISP), ( _RR ), ( _CR )
Are resistors and capacitors for resetting the microcomputer (μC), (D1) and (D2) are diodes for preventing reverse charging, and (CyL) is a crystal oscillator that supplies a clock to the microcomputer (μC).

Next, the switches will be described. (S1) is a shooting preparation switch which is turned on by first pressing a release button (not shown),
(SISO) is a film sensitivity change switch for changing the film sensitivity. This switch (SISO) and
When the down switches (Su) and (Sd) are pressed (ON), the film sensitivity setting value is changed. The AND circuit (AN1) is activated by turning on either the shooting preparation switch (S1) or the film sensitivity change switch (SISO).
Output changes from a high level (hereinafter “H” level) to a low level (hereinafter “L” level), whereby the microcomputer (μC) performs a predetermined operation. (S2) is a release switch that is turned on by the second depression of the release button (deeper than the first depression). The microcomputer (μC) is
When the change signal from "H" level to "L" level is input by ON, the release routine is executed and the exposure control,
After that, control such as film winding is performed. (S
3) is an exposure completion switch that turns on when the exposure is completed. It is turned off by a charging mechanism (not shown) while the film is being wound.
Is done. (S4) is turned on when the winding of one frame is completed, and is turned off by a mechanism (not shown) when released. (S5)
Is a back cover close detection switch, which is turned on when the back cover of the camera is closed, and when a signal that changes from "H" level to "L" level by this ON is input to the microcomputer (μC), The microcomputer (μC) executes a back cover ON interrupt routine, which will be described later, and performs predetermined control. (S6) is a film detection switch that detects the presence or absence of a film.This switch is pulled up to the power supply via a resistor and a spool of the film winding chamber made of conductive rubber that is in contact with the ground. It turns off when the film is wound around the spool. (Su), (S
Reference numeral d) is an up / down switch, which can be turned up or down by turning on together with the switch for the information to be changed when the information to be changed is moved up (moved up) or down (moved down).

Next, the operation of the camera will be described with reference to the flow chart of the microcomputer (μC) shown in FIG.

<Battery replacement> When the battery is replaced and a new battery is installed in the camera, the reset resistor (R _R ): capacitor (C _R ) through the reset terminal (RE) of the microcomputer (μC) to the “L” level. When a signal that changes from "H" to "H" level is input, the microcomputer (μC) executes the flowchart shown in FIG.

First, the microcomputer (μC) resets all internal registers and flags, and then outputs (O) and ports (O).
P) is set to "L" level (# 5, # 10). Next, the data stored in the E ² PROM is taken into the internal register (#
15). This data acquisition is performed by executing the subroutine shown in FIG. Before describing this subroutine, the address of the E ² PROM and the data input to this address will be described based on Table 1.
The microcomputer (μC) and E ² PROM used have an 8-bit configuration.

First, at the address "00" of the E ² PROM, the total number of release operations for release operation is input in 10,000 units, and (b0, b1, b2) = (0,0,0), (1, 0,0), (0,1,0)
(1,1,0) (☆, ☆, 1), where N is the total number of releases, N ≤ 10,000, 10,000 <N ≤ 20,000, <N ≤ 30,000, <N ≦ 40,000 and N> 40,000. This is used to relieve the memory limit for rewriting the total number of releases due to the limitation on the number of rewriting of the E ² PROM, or rewriting the number of photographed films. Specifically, the number of rewriting is guaranteed 1 Ten thousand units are detected by the above bits,
As a result, if it is detected that rewriting has been performed 10,000 times, the rewriting byte (address) is changed. Addresses (01), (11), (21), (31)
The contents of the lower 8 bits of the total number of releases are to be memorized. If the release is 10,000 times or less, the address (01) is the memory, and if the release is 10,000 or more and 20,000 or less, the address (1
Memory of 1) Addresses above 20,000 and below 30,000 (21)
Memory of 30,000 and 40,000 or less, the memory of the address (31) is used. Address (02), (12), (22),
The contents of the upper 8 bits of the total number of releases are stored in (32), and the addresses (01), (11), (21),
It is used as a 16-bit configuration in pairs with (31), and the memory use address for the total number of releases at that time corresponds to (01), (11), (21), (31). . The addresses (03), (13), (23), and (33) store the number of photo films, and are used properly according to the total number of releases, as described above. The address (04) stores the film sensitivity. Since the number of times the film sensitivity is changed (rewriting) is small, no spare bit is provided.

Returning to the flowchart, the flow of the data reading subroutine from the E ² PROM shown in FIGS. 3 (I) and (II) will be described.

First, the microcomputer (μC) prohibits all interrupts to this flow so that the data will not become incorrect while reading the data (# 100). Next, the address "0" of the data to be read is set and the subroutine for reading the data from the E ² PROM is executed (# 105, # 110). This subroutine is shown in FIG. 3 (II) and explained. First, the data of the set address (currently address 0 is set) is output to the address bus, and the / R signal is set to "H" level. Set the read mode (as seen from the microcomputer) (# 255), set the chip enable pin (CE) to the "H" level (# 260), and make sure that the E ² PROM is in the read mode for the data at the above address. Make it latch. The E ² PROM internally decodes the latched address, outputs the data (DA) at that address to the data bus, and
C) inputs this data (DA) (# 265). In this flowchart, the chip enable signal (CE) is output from the microcomputer (μC) and the data (DA) is input immediately. However, if the processing speed of the microcomputer (μC) is high, the chip enable signal After outputting (CE), a step waiting for time may be provided. After inputting the data (DA), the microcomputer (μC) sets the chip enable signal (CE) to the “L” level to end the reading of 1-byte data (# 270) and return (see FIG. 3 (I ) To step # 115). In step # 115, this data (DA) is output to the register (0), b1 and b0 of the data are determined, and the address of the E ² PROM in which the data of the total release number and the number of photographed films is stored is detected. To do. First, if (b1, b0) = “00” is determined in step # 120, the number of rewrites (N) is 10,000 or less as described in Table 1, so the addressing variable is determined in step # 125. Set R1 to 1. When (b1, b0) = "01"(# 130), 10,000 times <N≤20,000 times, so R1 is set to 11 (#
135), (b1, b0) = "10"(# 135), 20,000 times <
Since N ≦ 30,000 times, R1 is 21 (# 145), (b1, b0) =
When “11”, 30,000 times <N ≦ 40,000 times, so R1 is set to 31 (# 150). This addressing variable R1 indicates the address in which the lower 8-bit data of the total number of releases is stored. Next, the register designation variable R2 is set to "1"(# 155), the address is set to the above R1 (# 160),
First, the lower 8 bits of the total number of releases are set to E ² PROM
Read (# 165) from this data DA
The data is stored in the register (1) in C) (# 170). Then, add "1" to the addressing variable R1
R1 (# 175), register addition variable R2 plus "1" is newly set as R2 (# 180), and repeated until R2 becomes "4"(# 185). The 8-bit data is read from the E ² PROM into the register (2), and the data of the number of photographed films is read from the E ² PROM and stored into the register (3) (# 160).
~ # 185). Then, the sensitivity data of the remaining film is
^{2 To} read from the PROM, set the address (R1) of the microcomputer (μC) to "4"(# 190), read the data (# 195),
After storing this data (DA) in the internal register (4) (# 200), enable interrupts and return (# 20).
Five). This completes reading the E ² PROM data into the register.

When this reading is completed, the microcomputer (μC)
In step # 20 in the figure, it is determined whether either the shooting preparation switch (S1) or the film sensitivity change switch (SISO) (SA) is turned on. When both switches are OFF, it is determined whether the end flag (ENDF) is set (# 25), and if set, the process returns to step # 20. If not set, the power supply transistor (Tr1) and Set terminals (01) and (03) to "L" level to turn off the DC-DC converter (# 30, 35).
Then, the end flag (EMDF) is set, all the displays are turned off, and the process returns to step # 20 (# 40, # 42).

At step # 20, either the shooting preparation switch (S1) or the film sensitivity change switch (SISO) is turned on.
If so, the process proceeds to step # 45 to reset the end flag (ENDF) and then reset and start the timer (# 50). This timer is a microcomputer (μ
It is a hard timer built in C) and is used for holding power. The timer is reset and started, and the terminal (01) is set to "H" level to turn on the power supply transistor (Tr1) (# 55). Next, set the terminal (03) to "H" level to turn on the DC-DC converter (# 6
0) Even if the power supply voltage drops, a constant voltage is supplied to the microcomputer (μC) and E ² PROM. Then, it is judged whether or not the film sensitivity change switch (SISO) is turned on (# 65), and if it is turned on, the process proceeds to the film sensitivity change (ISO change) subroutine (# 70).

<ISO change> This ISO change subroutine is shown in FIG. 4 (I) and explained. First, the contents stored in the SV register (SvR) are read, this is set as Sv (# 300), and this value is displayed. Output to the device. The display device (DISP) is shown in Fig. 4 (II).
Of the displays shown in Use only to display film sensitivity (# 305).
This Sv is displayed as an apex value. Next, the microcomputer (μC) uses the film sensitivity change switch (SISO)
Is turned on (# 310), and if it is turned on, it is determined whether any of the up switch (Su) and down switch (Sd) is turned on (# 315, # 325),
When the up switch (Su) is ON, 0.5 is added to the film sensitivity (Sv) (# 320), and when the down switch (Sd) is ON, the film sensitivity (Sv) is
Subtract 0.5 from this to obtain a new film sensitivity (Sv) (# 3
30). Then, the process proceeds to step # 335, waits for a certain period of time to avoid continuous changes, and returns to step # 305.

Both up switch (Su) and down switch (Sd) are ON
If not, step # 325 to step # 305
Then, this flow is repeated and the film sensitivity is displayed. In step # 310, the microcomputer (μ
When C) detects that the film sensitivity change switch (SISO) is turned off, it judges whether the film sensitivity (SvR) stored in the SV register (SvR) is equal to the changed film sensitivity (Sv). (# 340), return to the original flow if they are equal, and if they are not equal, proceed to the ISO writing subroutine (# 345) to write the changed film sensitivity (Sv) to the E ² PROM, and write. After finishing, return. Thus, the modified film sensitivity (Sv), when the film sensitivity is memory (svr) is equal to E ² PROM, without writing to the E ² PROM, by reducing the number of writes, E ² It is possible to effectively deal with the limitation of the number of times of writing for PROM.

Next, the ISO writing subroutine shown in FIG. 5 will be explained. First, the changed film sensitivity (Sv) is stored in the SV register (SvR), and the E ² PROM address to be written is set to "4". Then, the content (SvR) of the SV register (SvR) is set in the data output register, the process proceeds to the write subroutine (# 365), and after the write is completed, the process returns.

The above-mentioned write subroutine is shown in FIG. 6 and explained. First, the microcomputer (μC) prohibits the destruction of data by prohibiting an interrupt occurring during the write (# 400). And write / read terminal (/ R) "L"
The level is set (# 405), the writing mode is set, and the data of the address "4" set above is output (# 410, # 41).
Five). Next, the chip enable (CE) is set to the “H” level to start writing in the E ² PROM (# 420, # 42).
Five). While writing to the E ² PROM, the Write Busy terminal (WB
u) outputs “H” level, and when writing is completed, outputs “L” level. The microcomputer (μC) waits until this end signal becomes “L” level (# 430). When this signal is detected, the chip enable is set to “L” level (# 435), and the end of the write mode is written to the E ² PROM. Output
Enable interrupts and return (# 435). The above Wri
If the terminal does not have the te Busy terminal (W · Bu), the time required for writing may be measured and the waiting time may be waited.

 This is the end of the ISO change subroutine.

<Preparation for shooting> In step # 65 in FIG. 2, if the film sensitivity change switch (SISO) is not turned on, preparation for shooting (S1
ON) subroutine.

This subroutine is shown in FIG. 7 and explained. The microcomputer (μC) determines the open photometry value (Bvo) from the photometry circuit (LMC) and lens circuit (LEC) that are driven by turning on the power supply transistor (Tr1). Enter the maximum aperture value (Avo) respectively (# 450, # 455).

Next, it is judged whether or not the film is loaded (# 46
0), the flag (FILF) with film is set if loaded (# 465), and the flag (FILF) is reset if not loaded (# 470).

Then, the film sensitivity (SvR) stored in the SV register (SvR) is read (# 475), and a predetermined exposure calculation is performed from the above-mentioned open photometry value (Bvo), lens open aperture value (Avo), and film sensitivity (Sv). (# 480), the shutter speed, control aperture value, and shooting data obtained by this calculation are displayed on the display device (DIS).
P) and display To display and return (# 490).

Returning to FIG. 2, when the microcomputer (μC) finishes the ISO change or S1ON subroutine (# 70, # 75), either the shooting preparation switch (S1) or the film sensitivity change switch (SISO) is turned on. It is determined whether or not (# 80), and if either one is ON, step # 45.
Return and repeat the routine. Which switch (S
If 1) and (SISO) are also OFF, determine whether the timer started in step # 50 has passed 10 seconds (#
85), if it has elapsed, the process proceeds to step # 30 to end the shooting, and if 10 seconds have not elapsed, the process returns to step # 55 to repeat the routine and wait for the shutter release.

<Shutter Release> Next, when the release switch (S2) is turned on, the microcomputer (μC) performs a control process for photographing shown in FIG.

First, the microcomputer (μC) prohibits interrupts other than the battery replacement interrupt BATINT (# 500), and controls the release operation and the exposure (# 505). The exposure is controlled by the front curtain (1 curtain) and the rear curtain (2 curtains) of the focal plane shutter.
This is done by sending a travel start signal for the curtain) to the exposure control circuit. When the exposure is completed (# 510 → # 512), the exposure completion switch (S3) indicating this is turned on and the microcomputer (μ
C) is the bit of the register of address "0" in the microcomputer (μC) when the ON signal of this switch (S3) is input.
If b2 is 1, that is, the number of rewrites (N) has exceeded 40,000 times (# 512), and if set, then E ² PRO
Even if the contents of M are rewritten, the data thereafter is not trusted, and the process is not rewritten, and the process proceeds to the film winding subroutine of step # 570. This subroutine will be described later. When the bit b2 is not "1", the microcomputer (μC) adds "1" to the lower counter (CNTR1) of the total number of release times (# 515), and this value is "0", that is, from the lower 8 bits. Whether there was a carry of
520), if there is a carry, the upper counter (CNT
Add "1" to R2) (# 525). Then, the process proceeds to an address change subroutine (# 530) for designating an address to be changed according to the number of times of writing. Lower counter (C
Even if NTR1) is not "0", proceed to the address change subroutine.

This address change subroutine is shown in FIG. 9 and explained. The microcomputer (μC) judges whether or not the contents of the upper and lower counters (CNTR2, CNTR1) are 10,000 or less, and if it is 10,000 or less, If there is, the addressing variable R1 indicating the address for writing the total number of releases is set to "1" and the process returns (# 600 to # 605).

The microcomputer (μC) executes the steps from step # 615 if the content of the counter (N is set to N) is 10,000 <N ≦ 20,000. In step # 615, it is determined whether or not the bit (b0, b1) indicating the tens of thousands of the total number of releases is (0,0). When it is (0,0), it is assumed that the first total release number exceeds 10,000 times, that is, 10,001 times,
Set bits (b0, b1) to (0,1), set the data transfer register to "1", that is, (b0, b1) = (0,1) data and set the E ² PROM address to " Set it to 0 "and proceed to the write subroutine to write this (# 620 to # 635).

Next, the specified number of addresses R1 for writing the total number of releases
Set to 11 and return (# 640). Even when the above bit (b0, b1) is not (0,0), the process proceeds to step # 640 and the same process is performed. The contents of the counter (CNTR1) (CNTR2) of the microcomputer (μC) are 20,000 <N ≤ 30,000, 30,000 <N ≤
If it is 40,000, the same processing as the above 10,000 <N ≦ 20,000 is performed. If the counter content is 20,000 <N ≦ 30,000, it is determined whether or not the bit content (b0, b1) = (0,1), and (0,
If it is 1), it is assumed that it has exceeded 20,000, and this is (1,0),
The address is set to "0", and the process proceeds to the write subroutine. Writing to the E ² PROM is performed, the address specification variable R1 is set to "21", and the process returns (# 650 to 675). Address specification variable R1 unless bit (b0, b1) = (0,1)
Set to “21” and return. Similarly, the counter (C
If the content of NTR1) (CNTR2) is 30,000 <N ≦ 40,000, it is determined whether the content of bit (b0, b1) is (1,0), and (1,
If it is 0), it is considered that it exceeds 30,000, and the above bits (b0, b1)
Set to (1,1), set the address to “0”,
Proceed to write subroutine and write to E ² PROM (# 685 to # 7
05). Then, the addressing variable R1 is set to "31" and the process returns (# 710). If the bits (b0, b1) are not (1.0), set the addressing variable R1 to "31" and return. The contents of counters (CNTR1) and (CNTR2) are 4
If it exceeds 10,000, set the bit (b0, b1, b2) of address 0 of the microcomputer (μC) to (0,0,1), output the warning display data to the display device, and set the data to "4". set(#
715 to # 725). Then, set the address to "0" and E ²
Write the data of bits (b0, b1, b2) to PROM, set the addressing variable R1 to "31" and return. This warning is displayed in order to have the service station of the camera inspect that the release operation has been performed 40,000 times. The number of times is not limited to 40,000, but may be tens of thousands, and if 50,000 or more, E ²
Increase the memory for PROM release rewriting.

Returning to FIG. 8, the microcomputer (μC) sets the addressing variable R1 in the address register, first sets the contents of the lower counter (CNTR1) to the data and proceeds to the write subroutine to write the data ( # 535-545).
Next, add "1" to the addressing variable R1 to make it the address of the E ² PROM for the upper bits, set this in the address register, and set the contents of the upper counter (CNTR2) to the data. Proceed to the write subroutine and write the data (# 550 to # 565).

When the rewriting of data is completed, the microcomputer (μC) performs the film winding process (# 570).

<Film winding> Fig. 10 shows the winding subroutine. First, the microcomputer (μC) outputs a signal for turning off the winding motor (M) to the winding circuit (MOD) from the terminal (02) by prohibiting interrupts other than the interrupt of the back cover and the battery replacement interrupt (BATINT) (# 75).
0, # 755). And wait for the winding to be completed (# 760),
When the winding completion switch (S4) is turned on, this is detected and a signal for stopping the motor is output (# 765). Next, a flag indicating whether or not there is a film (FILF)
Is set (# 770), and if it is set, it is determined whether bit b2 of the address (0) in the microcomputer is "1"(# 773). If there is no film or if the number of rewritings (N) of the E ² PROM exceeds 40,000 (b2 = 1), the number of film-recorded films shown below is not rewritten and the split is allowed. And then return (# 772). If there is a film and it has not exceeded 40,000 times, in step # 775, add 1 to the variable NR indicating the number of shot films and add "2" to the addressing variable R1 to set the address for writing the number of shot films. Ask (# 780). Then, the addressing variable R1 is set, the data NR is set, the process proceeds to the write subroutine (# 795), the number of photographed films is written in the E ² PROM, and the process returns (# 790 to # 795).

<Cover of Back Cover> Next, the operation of the camera when the back cover is changed from the open state to the closed state will be described with reference to the flow chart of the microcomputer (μC) shown in FIGS. 11 to 12.

When the back cover is closed, the back cover close detection switch (S5) is turned on.
Then, when a signal that changes from the “H” level to the “L” level is input to the microcomputer (μC), the microcomputer (μC)
The back cover ON writing routine shown in FIG. 11 is executed.
First, the microcomputer (μC) detects in step # 800 whether or not the film is loaded (wrapped around the spool). If the film is loaded, the back cover is opened by mistake. And proceed to step # 815 without initial loading. If no film is loaded, proceed to the initial load (initial winding) subroutine (# 805).

This initial load subroutine is shown in Fig. 12,
To explain, first, the microcomputer (μC) sets the variable indicating the number NR of photographed films to “0” and turns on the winding motor (M).
To start winding (# 900, # 90
Five). Wait until the winding is completed in step # 910, and when the winding is completed, add "1" to the above variable NR and add this variable.
The above winding operation is repeated until the NR reaches 3 (# 91
5, # 920). When the variable NR is 3, that is, when the initial winding is completed, the winding motor (M) is stopped, the variable NR is reset to "0", and the process returns (# 925, # 930).

Returning to FIG. 11, the microcomputer (μC) determines whether the film is loaded (# 810) after finishing the initial loading process (# 805), and sets the flag (FILF) when loaded. (# 815), and whether the film is a DX film whose film sensitivity is formed by an electric pattern on the container (# 82).
Five). This detection can be performed by a known method, specifically, by determining whether or not at least one of the lower 2 bits indicating the film sensitivity is in a conductive state with the common terminal on the film container. When the film used is a DX film, the film sensitivity Sv is automatically read and the data indicating this value is output to the display device (# 830, # 840). When the film is not loaded, the film flag (FILF) is reset (# 82
0). When the film is not loaded or when it is loaded but is not the DX film, the film sensitivity (SvR) stored in the register is set to Sv (# 835),
This value is output to the display device and displayed (# 83
5, # 840). Next, stored film sensitivity (SvR)
And the above film sensitivity (Sv) are compared. If they are not the same,
Proceed to the ISO writing subroutine (# 850) and write the film sensitivity (Sv) to the E ² PROM (# 845, # 850). If they are the same, skip step # 850, do not write to the E ² PROM, proceed to step # 855, and end flag (END
If F) is set, it returns to the SA routine if it is set, and returns to the step before the interrupt if it is not set.

Next, the battery voltage drops, and the microcomputer (μC), E ² PROM
When the voltage of the battery check circuit (BC) is slightly higher than the voltage that causes malfunction of other circuits, the signal indicating this is input from the battery check circuit (BC) to the microcomputer (μC). Execute the indicated BATINT routine. Microcomputer (μC) sets all output terminals to “L”
Turn to level and stop (# 950). The stop here means a control for stopping the clock as well.

Second Embodiment Next, a second embodiment will be shown. In the above-described embodiment, the writing of the total number of release times is always performed by using the upper 8 bits and the lower 8 bits, but the upper 8 bits are rewritten each time even though they are changed only once every 256 times. It takes longer time, consumes more current (power), and requires more than one spare memory in the E ² PROM due to the limited number of rewrites. The purpose of this modification is to eliminate these drawbacks, and the upper 8 bits are rewritten only when the contents of these 8 bits change.

In this embodiment, the contents of the memory of the E ² PROM are changed in accordance with the change, and this is shown in Table 2 and only the changed points will be described.

First, at address "00" of the E ² PROM, upper 8 bits of data indicating the total number of releases are stored. In this case, since rewriting is done once every 256 times as described above,
For example, if you count up to 40,000 times, 40,000 / 256 = 156.25
Only rewriting (156 times) is performed, and no spare byte is required for the rewriting number limit (10,000 times). The other changes are that the address of the E ² PROM (02,12,22,3
2) is eliminated, and the address (00) shown in Table 1 is eliminated. This is the top 8 of the total release times.
This is because an attempt was made to determine the total number of releases from the bit. Changes in the flow chart of the microcomputer (μC) for executing these are shown in FIGS. 14 to 16.

FIG. 14 is a modification of step # 15 shown in FIG. First of all, it prohibits all of the interrupt at step # 1000, E ²
Set the PROM address to "00"(# 1005). Then, the content DA corresponding to this address is read from the E ² PROM, and this is set to the address “0” of the register in the microcomputer (μC) (# 1010, # 1015). The contents of this counter (CNTR2) are decoded and this value is 39 or less (998
4 times), set the addressing variable R1 to “1” (# 1020, # 102
5) Similarly, the content of the counter (CNTR2) is 78 or less (19968
If the address specification variable R1 is “11” (# 1030, # 103)
5), if the content of the counter (CNTR2) is 117 or less (29952 times), set the addressing variable R1 to "21"(# 1040, # 1045), and if the content of the counter (CNTR2) is 156 or less (39936 times), the addressing variable Set R1 to “31” (# 1047, # 1050) and proceed to step # 1055. When the content of the counter (CNTR2) exceeds 156, the warning data indicating that the E ² PROM rewrite limit has been exceeded is output to the display device (DISP) and the E ² PROM
Without rewriting, proceed to step # 1090. The following is
It is almost the same as Fig. 3 (I), but with the change of the memory contents of E ² PROM, in step # 1075 corresponding to step # 175, it is changed to R1 ← R1 + 2, and further corresponds to step # 180. In step # 1090, the address is changed to "4".

FIG. 15 is a modification of the release routine shown in FIG. First, the microcomputer (μC) prohibits interrupts other than BATINT to perform exposure control (# 1150, # 1155).
When the exposure control is completed (# 1160) and the upper 8-bit counter (CNTR2) exceeds 156, the warning data indicating that the E ² PROM rewrite limit has been exceeded is output and the film is wound. To the subroutine of (# 1170 → #
1240). If the counter (CNTR2) is 156 or less, add "1" to the lower 8-bit counter (CNTR1) to determine whether this value is "0", that is, whether carry to the upper position has been performed (# 1175, # 1180). When this value is "0", it is considered that a carry has been performed, and the upper 8-bit counter (CNTR2)
Add "1" to, set it in the register for E ² PROM output, set address "0" in the register for address, and proceed to the write subroutine to write to E ² PROM. Proceed to step # 1205 (# 1185 to # 1200).

If the counter (CNTR1) is not "0", no carry has been performed, so the upper 8 bits are changed and the E ² PROM is changed.
Without rewriting to, proceed to step # 1205.

Next, the microcomputer checks the contents of the counter of the upper 8-bit counter (CNTR2), and if this content is 39 or less, set the addressing variable R1 to "1" (steps # 1205, # 1210), and if this content is 78 or less, specify the address. If the content of the variable R1 is "11" (steps # 1215, # 1220) and less than 117, the addressing variable R1 is "21" (steps # 1225, # 1230),
When the value exceeds 117, the address designation variable R1 is set to "31" (step # 1235) and the lower 8 bits of data and address R1
Is set in the E ² PROM output register, writing is performed, and the process proceeds to winding (# 1245 to # 1260).

FIG. 16 shows a subroutine for performing this winding process. This is a step of checking the contents of the upper 8-bit counter (CNTR2) instead of step # 773 shown in FIG. 10, and this value is 156 or less. When step # 1
In step 130, the number of photographed films is rewritten to the E ² PROM. If the number exceeds 156, the process proceeds to step # 1355 so that the E ² PROM is not rewritten. Other than that, it is similar to FIG.

<Third Embodiment> In a third embodiment shown below, the timing of writing the total number of releases and the number of photographed films to the E ² PROM is set to the timing of turning off the two curtains (starting the two curtain travel). I try to do it at the time. The reason for this is up to the point of complete exposure from the running at the start of the second act (Act 2 traveling completion), the control of the camera anything it is not necessary to perform, since has become a tired time, by using this time, E ² This is for more efficient sequence control by writing to the PROM. This is especially effective for continuous shooting. The flowchart in that case is shown in FIG. 17 and FIG.

FIG. 17 is a modification of FIG. 15. When the release operation is started, the microcomputer first disables interrupts to this flow other than BATINT (# 1150), and then controls the exposure control circuit (AEC). Release operation (operation up to the start of exposure such as mirror up) (# 1151 ') (this may be controlled by a timer or a switch for detecting the completion of mirror up may be used to control the release operation). Then, turn off one of the focal plane shutters (start one-curtain running).
(# 1152 '), after the exposure time elapses (# 1153'), OF 2 acts
F to start (two-curtain running (# 1154 ').

Next, write the total number of releases to E ² PROM (# 1170-
# 1255) (explanation omitted), then in step # 1400,
Write the number of taken films to E ² PROM. Then, after the exposure is completed (two-curtain running is completed), when the exposure is completed, winding control is performed and the routine proceeds to SA (# 140
3, # 1406, # 1410, # 1413, # 1420).

FIG. 18 shows a subroutine for rewriting the number of photographed films. This is the film winding routine part (# 1300- #) of the flowchart for updating the number of films shown in FIG.
1315) is omitted, and the corresponding step numbers are given and duplicate explanations are omitted.

<Fourth Embodiment> In a fourth embodiment shown below, the total number of releases is stopped from being written every time each release is made, and the number of times collected to some extent is set as one unit, and the number of times in this unit is written. I tried to go. By doing so, the spare bytes are eliminated, the current consumption is reduced as much as possible, and the time required for this (writing of E ² PROM) is shortened.

However, in this case, when the battery is removed, the total number of releases stored in the register in the microcomputer (μC) is erased, so the number of times that does not reach 1 unit is canceled and becomes “0”, This erased number of times is an error with respect to the accurate total number of releases,
Since the number of batteries that can be converted within 10,000 shots is large, it does not cause a large error. For example, the release count for one unit is "5", and when a new battery is inserted, the number of shots that can be taken with this battery is 500 (more than 20 for a film with 24 shots).
Then, out of 10,000 shootings, the battery is replaced 20 times, and if the average number of releases that are canceled when the battery is replaced is 2.5, 20 x 2.5 = 50 is the error amount within 10,000, which is 0.5%.
It is only the error of.

In the fourth embodiment, the introduction of one unit described above
The address of the E ² PROM and its contents are changed by deleting the addresses (11), (21), (31) and the memory required for them of the lower 8-bit spare bytes of the total release count as compared with Table 2. There is a point, but other than this it is the same.

Figures 19 to 21 show the microcomputer (μ
The flowchart of C) is shown. 19 to 21 are the third
14 to 16 showing the embodiment of FIG.

First, referring to FIG. 19, the microcomputer (μC) prohibits all interrupts (# 2000), and in steps # 2005 to # 2030, addresses “0” and “0” stored in the E ² PROM are stored. Data of upper 8 bits and lower 8 bits of "1" are read and stored in predetermined registers "0" and "1" (hereinafter, these registers are counter (CNTR2) (CNT
R1) say).

Now, if the number of release times for one unit is "5",
The number of releases reaches 10,000 when the number of registers (counters (CNTR1) and (CNTR2)) reaches 2000.

The microcomputer (μC) decodes the contents of the counter, and when the area is "24" or less, the value of the counter is 2,000 or less (10,000 times or less), so the addressing variable R1 is set to " In 3 "(# 2035 → # 2040), when the decoded value of the counter is" 44 "or less, the value content of the counter is 4,000 or less (20,000 times or less), so the addressing variable R1 is set to" 13 ". In (# 2045 → # 2050), when the decoded value of the counter is "64" or less, the counter value is 6,000 or less (30,000 times or less), so the addressing variable R1 is set to "23". (# 2055 → # 2060) When the decode value of the counter is "84" or less, the counter value is 8,000 or less (40,000 times or less), so the addressing variable R1 is set to "33", respectively. Set (# 2085), E ² PROM
Data DA (number of films) is read out (# 2090), stored in a predetermined register (R2) (# 2095),
Go to step # 2100. The content of the above counter is 8,000 (4
If it exceeds 100,000, the warning display data is output to the display device and the process proceeds to step # 2100 (# 2097). Next, the microcomputer (μC) sets the address to “4”, goes to read the E ² PROM data, and stores it in a predetermined register (#
2100 ~ # 2110). Then, a variable K for counting one unit is set to 0, interrupts are enabled, and the process returns (# 211
5, # 2220).

Next, the flow chart shown in FIG. 20 corresponds to the flow chart shown in FIG.
Step # 1170 in FIG. 15 is changed to step # 2300, and three steps for determining whether or not the number of releases has reached one unit are added below this step. Steps # 1205 to # 1235 are stepped. The points are # 2320 to # 2350, and step # 1250 is step # 2355. Describing in order from the top, in the fourth embodiment, writing is performed once when the release is performed five times, so it is determined whether or not the content of the counter is 8,000 or less (40,000 times). If it exceeds 8,000, a warning is displayed (# 2358). If it does not exceed 8,000, 1 is added to the variable K for judging 1 unit to newly set K (# 2305), and it is judged whether or not it becomes "5"(# 2310). If this variable K is less than 5, then E ² PR
Do not write the OM and proceed to the winding subroutine to perform the winding process (# 2360). When the variable K becomes "5", it is set to "0"(# 2351) and the writing process to the E ² PROM is performed (# 2311 to # 2316).

As described above, since the total release count is 5 and writing is performed once, the contents of the counter in units of 10,000 times are changed, and this counter (CNTR1, CNTR2)
When the decode value of is less than "24", the addressing variable R1
To “3” (# 2320 → # 2325), set this counter (CNTR1, CN
TR2) Decoded value is less than or equal to "44" Addressing variable
Set R1 to “13” (# 2330 → # 2335) and set this counter (CNTR
When the decoded value of (1, CNTR2) is "64" or less, the addressing variable R1 is set to "23"(# 2340 → # 2345), and this counter (C
If the decoded value of NTR1, CNTR2) exceeds "64", the addressing variable R1 is set to "33"(# 2350). Note that this addressing variable R1 is the E ² PR of the number of photographed films of the film.
This is the address of the OM. After the addressing variable R1 is set, the lower 8-bit counter (CNTR1) data is set (# 2352) and the address is set to "1"(# 235
5) Proceed to the write routine, and set data to E ² PRO
Write to M (# 2357), and execute the winding subroutine after writing (# 2360).

The flowchart shown in FIG. 21 corresponds to the flowchart shown in FIG. 16, in which step # 1335 for setting the address value is deleted and step # 1325 is replaced with step # 2360.
It is the same as the flowchart of FIG. 16 except that it is changed to. This change is accompanied by the fact that the total number of releases is 5, and the writing is performed once. For other steps, the corresponding step numbers in FIG. 16 are given and the description thereof is omitted.

<Fifth Embodiment> A fifth embodiment shown below is intended to count the total number of releases using the number of used films. Specifically, when a film is loaded, The number of films of the film is read from the electrically indicated pattern, and the total number of releases is standardized by this number. The number of films for this standardization is 12, and the total number of releases 12 is 1 as a unit, and "1" is added to the counter. That is, in this embodiment, instead of counting the actual number of releases, the number of films is used as a substitute, and in the fourth example, the number of releases is 5 as one unit.
The number of times is one unit.

Therefore, the release count of 10,000 is 83
3 (actual total release number is 9996 times), similarly 20,000 times as count value 1666 (19992), 30,000 times as count value 2499 (29988), 40,000 times as count value 3332 (39984). It should be noted that the count value becomes 2500 after 30,000 times, but when it is set to 2500, it becomes 10 between 20,000 times and exceeds 10,000, so it is not adopted.

A flowchart for implementing this is shown in Figs.
Shown in the figure.

The flow chart of FIG. 22 corresponds to the flow chart of FIG. 19, and since the unit of standardization of the number of rewrites is different, the numerical values in step # 2035, step # 2045, step # 2055, step # 2065 in FIG. To step # 2400,
In step # 2410, step # 2420, and step # 2430, the count values are changed as described above, and the other steps have the same step numbers as those in FIG. 19 and the description thereof will be omitted. The resetting of the variable K in step # 2115 in FIG. 19 is omitted because it is unnecessary in this embodiment.

In this case, the reading of the number of films may be performed in a back lid closing subroutine (see FIG. 11) which is executed when a new film is loaded and the back lid is closed.
The flowchart shown in FIG. 23 is the same as the flowchart shown in FIG.
(0) is added, and the others are the same as in FIG. 11, so
The same step number is assigned and the description is omitted. This subroutine is shown in FIG. 24 and explained. First, the microcomputer (μ
C) judges whether the count value is 3332 or less (the total number of release times is about 40,000 times or less). If it exceeds this, the contents of the counters (CNTR1) and (CNTR2) are not rewritten, The warning display data is output to the display device and the process returns (# 2450, # 2452).

If the counter value is less than 3332, go to step # 2453.
If it is not a DX film, it is determined whether it is a DX film or not, and the process proceeds to step # 2480 to set the number of frequently used films. At present, the most commonly used film is for taking 36 images, so the number of films is set to 36 and "3" is added to the counter (CNTR1). However, the number of films may be set to 24 and the process may proceed to step # 2470 to add "2" to the counter, or the both may be averaged to set the count value to 2.5. (However, at this time,
It is necessary to be able to count including the decimal point).

When the film is a DX film, it is determined whether the film is a 12-photo film, a 20- or 24-photo film, a 36-photo film, or a 72-photo film, respectively, step # 2455, step # 2465, step # 2475. 12 sheets, 20,24
If the number of sheets is 36, 72, step # 2460, # 247, respectively
For 0, # 2480, # 2485, the lower 8-bit counter (C
Add "1", "2", "3", "6" to the contents of NTR1) and set it in another counter (CNTR3), and proceed to step # 2490.

In step # 2490, the above two counters (CNTR3)
And (CNTR1) count values are compared. When the counter (CNTR3) is smaller, it is assumed that a carry has been performed, and the data obtained by adding 1 to the upper 8-bit counter (CNTR2) and its address "0" are set in the output register, respectively. Proceed to the write subroutine, write to the E ² PROM, and proceed to step # 2515 (# 2495 to # 25
Ten). When the counter (CNTR3) is larger, the upper 8 bits are not written and the process proceeds to step # 2515 to transfer the contents of this counter (CNTR3) to the counter (CNTR1).

The microcomputer (μC) determines and processes the count value of the counter (CNTR1) (CNTR2) as follows. That is, when it is 883 or less, the addressing variable R1 is set to “3” (# 2520 → # 25
25), when 1666 or less, the addressing variable R1 is set to "13"(# 2530 → # 2535), when it is 2499 or less, the addressing variable R1 is set to "23"(# 2540 → # 2545), exceeding 2499 When the addressing variable R1 is set to "33"(# 2540 → # 255
0), set each, and set the lower 8 bits of data and the addressing variable R1 in the registers for E ² PROM output (# 2555, # 2560), and proceed to the write subroutine to write to this data E ² PROM. Write and return (# 2565).

Furthermore, compared with the fourth embodiment, changes are required because it is not necessary to write the total release number when the exposure is completed, and the total release number is standardized by the number of films. Deleted steps # 2300 to # 2358 in FIG. 20 as shown in FIG. The modification by the latter is as shown in FIG. 26, step # 2360 of FIG. 21.
Step # 2600 corresponding to (CNTR2), (CNTR2
1) It can be dealt with by setting ≦ 3332.

Furthermore, by changing a part of the fifth embodiment,
Another modification is shown. In this modified example, when the back cover is opened while the film is loaded (the state where it is wound around the spool) and the film is removed, the number of shot films is displayed as "0" and "0" is displayed. To be rewritten to E ² PROM.

Flow charts in that case are shown in FIGS. 27 and 28.
FIG. 27 is a modification of the S1ON interrupt routine shown in FIG. 7, and indicates whether "0" is written instead of step # 470 in FIG. 7 when the film is not loaded. A subroutine (# 2700) for making a determination is provided.

 This subroutine is shown in FIG.

The microcomputer (μC) uses a flag (FI
LF) is set (# 2705), and if it is set, there is a film when this flow was executed last time, the film has disappeared this time, in other words, the film has been pulled out on the way. Then, the flow of writing "0" is performed. First, the flag is reset (# 2710).
Next, it is determined whether or not the count value of the total release counters (CNTR2, CNTR1) is 3332 or less (about 40,000 times) (# 2715). If it is 3332 or less, the variable NR of the number of photographed films is set to "0"(# 2720), and this data (NR) and addressing variable R1 are set in the data and address register for E ² PROM output, respectively (# 2725, # 2730), and proceed to the write subroutine to write this data “0” (# 273
Five). As a result, even if the film is removed, it will be displayed immediately in the subsequent steps and will go to writing to the E ² PROM immediately, so even if the battery is removed at this time and a new battery is installed, it is correct. The number of taken films is displayed.

In the twenty-eighth step, if the flag is not set in step # 2705 or if the predetermined number of times of rewriting is exceeded in step # 2715, no rewriting is performed and the process returns.

Although the number of rewritable times of the E ² PROM is set to 10,000 times in the above-described embodiments and modified examples, this is due to the existing E ² PROM.
It is the limit of, and if this number changes due to technological improvement,
The number of rewritable times in the embodiment and the modification may be changed accordingly.

Although the total number of releases is 40,000, it goes without saying that it may be larger or smaller than this.

If the release is performed simultaneously with the winding at the time of initial loading, this number may be counted as the release number.

In addition, in the embodiment and the modification, it is needless to say that the number of rewriting of the number of photographed films may be counted, and this can more accurately detect the number of rewriting of the number of photographed films. This includes a microcomputer (μC)
Therefore, it is sufficient to count the number of times, and to provide a memory of 2 bytes (counting 10,000 times) for storing the count value each time the E ² PROM is rewritten and a spare memory.

According to the present invention, the writing operation is performed only when it is determined that the film sensitivity needs to be rewritten, and the writing operation of the E ² PROM is performed only by performing the external operation for the sensitivity setting. Instead, the writing operation is performed in response to the release of the film sensitivity changing mode. As a result, the number of times E ² PROM is rewritten can be reduced.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a camera according to an embodiment of the present invention, FIG. 2 is a flowchart showing an interrupt routine at the time of battery replacement, and FIGS. 3 (I) and 3 (II) are E ² PROM to RA.
Flowchart showing reading of data to M, respectively,
FIG. (I) is a flow chart showing the ISO change subroutine, FIG. 4 (II) is a plan view of the display device, FIG. 5 is a flow chart showing the whole ISO writing subroutine, and FIG.
FIG. 7 is a flowchart showing a subroutine for ISO writing, FIG. 7 is a flowchart for showing a shooting preparation subroutine, FIG. 8 is a flowchart for showing control for shutter release, FIG. 9 is a flowchart for showing address change subroutine, and FIG. Is a flow chart showing a film winding subroutine, FIG. 11 is a flow chart showing control when the back cover is closed, FIG. 12 is a flow chart of initial load subroutine, FIG. 13 is a flow chart showing battery interruption, and FIG. 14 is a first modification. An example of the flowchart corresponding to FIG. 2, FIG. 15 is a flowchart illustrating a shutter release routine corresponding to FIG. 8, FIG. 16 is a flowchart corresponding to FIG. 10 showing a winding subroutine, and FIG. Flowchart showing the shutter release routine corresponding to the figure , FIG. 18 is a flow chart of recorded number of film frames rewriting subroutine, Fig. 19,
20 and 21 are flowcharts corresponding to FIGS. 14, 15, and 16, respectively, and FIGS. 22 and 23 are FIG. 19 and FIG. 19, respectively.
FIG. 11 is a flowchart corresponding to FIG. 11, FIG. 24 is a flowchart showing a film number reading subroutine, FIG. 25 is a flowchart showing a shutter release routine, FIG. 26 is a flowchart showing a film winding subroutine, and FIG. FIG. 28 is a flowchart showing the S1ON subroutine, and FIG. 28 is a flowchart showing the “0” write determination routine. μC: Microcomputer, E ² PROM: Writable / erasable ROM, S1
… Shooting preparation switch, S2… Release switch, SISO… IS
O change switch, Su, Sd… up / down switch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Ishimura 2-30 Azuchi-cho, Higashi-ku, Osaka City Minami Camera Co., Ltd. (72) Inventor Akihiko Fujino 2-30 Azuchi-cho, Higashi-ku, Osaka Osaka Kiki Building Minolta Camera Co., Ltd. (72) Inventor Hiroshi Otsuka 2-30 Azuchi-cho, Higashi-ku, Osaka Osaka Kokusai Building Minolta Camera Co., Ltd. (56) Reference JP-A-60-70428 (JP, A) JP 58-36077 (JP, A)

Claims (2)

(57) [Claims] 1. A control microcomputer is built-in, and an E ² PROM whose writing / erasing is electrically controlled by the control microcomputer is built-in.
The E ² PROM has at least a memory area for storing the film sensitivity, but it also has a mode setting means for setting the film sensitivity changing mode and a predetermined external operation when the film sensitivity changing mode is set. The film sensitivity setting means for setting the film sensitivity to be set, the rewriting judging means for judging whether or not the film sensitivity memory of the E ² PROM needs to be rewritten based on the set film sensitivity, and the rewriting judging means for rewriting. When it is determined that it is necessary, a writing means for writing the film sensitivity set by the film sensitivity setting means in the film sensitivity memory area of the E ² PROM in response to the release of the film sensitivity changing mode is provided. A camera with a built-in E ² PROM characterized by controlling the writing of film speed to the E ² PROM. 2. The rewriting judgment means judges that the rewriting is performed only when the film sensitivity set by the film sensitivity setting means is not equal to the film sensitivity currently stored in the E ² PROM. E ^{2 in} the range 1
Camera with built-in PROM.