JP4114035B2 - Electronic camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic device, and more particularly to a rewriting technique of a control program applied to a portable electronic device that can be driven by a battery such as a digital camera.
[0002]
[Prior art]
An electronic still camera that records an optical still image on a recording medium as digital data is known that can be rewritten by downloading the control program from the outside (Japanese Patent Laid-Open No. 7-225687). However, if the power supply is stopped or the rewriting fails while the program is being downloaded, the rewritten program is invalid and the camera will not operate normally.
[0003]
In Japanese Patent Application Laid-Open No. 7-225687, as one example, a flash ROM or a RAM connected to a backup battery is used as a rewritable program memory so that the program data can be stored even when the power supply voltage is shut off. ing.
[0004]
[Problems to be solved by the invention]
However, the technique disclosed in the above publication has a drawback that the camera cannot be normally started when the program is rewritten and the program becomes invalid.
[0005]
Further, in this publication, an embodiment is disclosed in which a RAM is used as a rewritable program memory, a program recorded in a recording medium is downloaded when the camera is activated, and an operation is executed. If there is no recording medium, it does not function as a camera, and a program must be downloaded every time the camera is activated.
[0006]
The present invention has been made in view of such circumstances, and when a program is rewritten illegally, such as when the power is stopped during program rewriting or the rewriting process fails, the device starts up normally. Electronics that can prevent it from disappearing camera The purpose is to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the object, the invention described in claim 1 An electronic camera comprising: an imaging unit that converts an optical image into an electrical signal; and a recording unit that records image data acquired via the imaging unit on a predetermined recording medium, Electronic camera A control circuit that controls the operation of the control circuit, a program memory that holds rewritable programs that define the processing steps of the control circuit, and the electronic camera An external power supply input means capable of supplying power from outside, a battery that can serve as a power supply source instead of the power supplied from the external power supply input means, Said Recording medium mounting means for detachably mounting the recording medium, a preliminary program for storing a processing program of the control circuit, a spare program memory in which rewriting of the preliminary program is prohibited, and the electronic camera And whether or not the recording medium is mounted on the recording medium mounting means and whether or not the recording medium is mounted on the recording medium mounting means is determined. If it is determined that the media is loaded, While turning on or blinking the viewfinder lamp or self-timer lamp, Reading the program stored using a part of the recording area of the recording medium from the recording medium and downloading the program to the program memory while being supplied with power from the battery If it is determined or if it is determined that the recording medium is not loaded in the recording medium loading means, the download circuit does not perform the download, and the control circuit, when the download fails , Using the spare program stored in the spare program memory with rewriting prohibited. camera Electronic, characterized by starting camera I will provide a.
The invention according to claim 2 is the invention according to claim 1, further comprising instruction means for instructing the start of the download, wherein the download means is instructed to start the download from the instruction means. When power is supplied from the battery, control for presenting a warning requesting connection of an external power supply is performed.
[0008]
The electronic device of the present invention can use an external power source such as an AC power adapter and a battery attached to the device as a power supply source. In normal equipment operation, it can be driven only by the battery. However, when performing an operation of writing a program to the program memory from the program providing means (hereinafter referred to as downloading), the use of the battery is necessary from the viewpoint of stable power supply. Is prohibited and power is supplied from an external power source. By doing this, interruption of the download process due to battery consumption can be avoided. For example, it is preferable to add a means for presenting a warning requesting the user to connect an external power source when an external power source is not connected when an instruction unit for instructing the start of download is operated.
[0009]
A central processing unit (CPU) can be used as the control circuit, and a nonvolatile memory such as a flash ROM is applied as the program memory. The program providing means may be a removable medium such as a memory card, and may be configured to receive program data from an external device such as a personal computer connected via a communication interface.
[0010]
According to a third aspect of the invention, in the invention of the first or second aspect, the control circuit is configured to download the electronic camera This is characterized in that the control from the power switch is invalidated and the power supply state is maintained.
[0011]
The invention according to claim 4 is the invention according to any one of claims 1 to 3, A voltage monitoring means for monitoring a power supply voltage supplied from the external power supply input means; and a power supply for switching the power supply source to the battery when the power supply voltage falls below a predetermined value during downloading. And a switching means.
[0012]
According to the present invention, even when the voltage of the external power supply suddenly drops due to an accident such as disconnection of the AC power adapter during the download, if the battery is attached to the electronic device, the power supply source is connected to the battery side. To continue the download process. As a result, download failure can be avoided.
[0015]
The roles of the program memory and the spare memory may be fixed in advance, or the roles may be switched using two program memories (a first program memory and a second program memory).
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, according to the attached drawings, camera A preferred embodiment of the present invention will be described.
[0018]
FIG. 1 is a perspective view of a digital camera according to an embodiment of the present invention. As shown in the figure, on the front surface of the camera 10, a photographing lens 12, a viewfinder window 14, a strobe 16, a strobe light control sensor 18, a microphone 19, and a self-timer lamp 20 are provided, and behind the photographing lens 12. A CCD image sensor (not shown in FIG. 1, described as 58 in FIG. 3) is disposed.
[0019]
On the upper surface of the camera, a shutter button 22, a power switch 24, a download button 25 for instructing start of download, and a strobe button 26 for switching a strobe shooting mode are arranged. The shutter button 22 is configured in a two-stage manner, and the automatic focus (AF) and automatic exposure control (AE) are activated in a “half-pressed” state in which the shutter button 22 is lightly pressed and stopped to lock AF and AE. Shooting is performed in the state of “full press”, which is further pressed from “half press”. The shutter button 22 is a means for giving an instruction to start recording a still image, and is also used as a video recording button (recording start / stop button).
[0020]
A speaker 28, an audio / video output terminal 30, a remote control terminal 31, a digital (USB) terminal 32, and a power input terminal 33 are provided on the camera side opposite to the grip portion 27. By connecting a connector of an AC power adapter (not shown) to the power input terminal 33, power can be supplied from the outside of the camera.
[0021]
A battery cover 34 that also serves as a slot cover for a recording medium (not shown in FIG. 1, described as reference numeral 78 in FIG. 3) is provided on the bottom surface of the camera. A battery storage chamber is formed.
[0022]
FIG. 2 is a rear view of the camera 10. On the back of the camera, a finder 36, a mode dial 38, a left key 40, a right key 42 and an up / down lever 44, a menu / execution key 46, a cancel / return key 48, a display key 50, a liquid crystal monitor 52, and the like are provided. ing. A finder lamp 37 is disposed on the side of the finder 36, and the operation state of the camera 10 is represented by a combination of a lighting color of the lamp and a lighting state (lighting / flashing).
[0023]
The finder lamp 37 is also used as an access lamp indicating that the program is being downloaded in a program rewriting operation to be described later. The self-timer lamp 20 shown in FIG. 1 may be used as an access lamp instead of or in combination with the finder lamp 37, or a dedicated lamp may be provided separately.
[0024]
The mode dial 38 shown in FIG. 2 is a means for changing the function (mode) of the camera. By rotating the mode dial 38, a shooting mode for performing still shooting, a playback mode for playing back captured images, Alternatively, it can be set to a movie mode for shooting a movie.
[0025]
The left key 40, the right key 42, and the up / down lever 44 are operation units for inputting instructions in the corresponding four directions (left, right, up, down), and the left key 40 and the right key 42 are respectively In the playback mode, it functions as a one-frame backward button and a one-frame forward button, and the up / down lever 44 is used as a zoom lever for adjusting the magnification in the playback zoom function or the electronic zoom function during shooting.
[0026]
The left key 40, the right key 42, and the up / down lever 44 are used to select a menu item from a menu screen displayed by pressing the menu / execution key 46, or to instruct selection of various setting items in each menu. Functions as a button. The menu / execution key 46 is used when a transition is made from the normal screen to the menu screen in each mode, or when the selection contents are confirmed and a process execution (confirmation) instruction is given. The cancel / return key 48 is used to cancel (cancel) an item selected from the menu or to return to the previous operation state. The display key 50 is an operation means for turning on / off the liquid crystal monitor 52 and switching between display / non-display of a reproduction method, a frame number being reproduced, and the like.
[0027]
When the display key 50 is pressed in the shooting mode or the movie mode, the liquid crystal monitor 52 can be switched ON / OFF. In the playback mode, every time the display key 50 is pressed from the state of “single frame playback (with on-screen display)”, “state without on-screen display” → “multi playback” → “single frame playback (on-screen display)”. Circulates as “...”. “Multi playback” is a playback method that displays a plurality of screens (for example, 9 screens in 3 rows and 3 columns) at a time.
[0028]
The liquid crystal monitor 52 can be used as an electronic viewfinder for checking the angle of view at the time of shooting, and can display a preview image of the shot image, a reproduced image read from the recording medium 78, and the like. The menu selection using the left key 40, the right key 42 and the up / down lever 44 and the setting of various setting items in each menu are also performed using the display screen of the liquid crystal monitor 52. Further, the LCD monitor 52 also displays information such as the number of storable frames (shootable time for movies), playback frame number display, presence / absence of flash emission, macro mode display, recording image quality (quality) display, pixel number display, and the like. Is displayed.
[0029]
FIG. 3 is a block diagram illustrating a configuration of the digital camera according to the present embodiment. The photographing lens 12 is composed of one or a plurality of lenses, and may be a single focus lens or a variable focal length such as a zoom lens. The light passing through the photographing lens 12 is incident on a CCD image sensor (hereinafter referred to as CCD) 58 after the amount of light is adjusted by a diaphragm (not shown). Photosensors are arranged in a plane on the light receiving surface of the CCD 58, and a subject image formed on the light receiving surface of the CCD 58 via the photographing lens 12 has an amount of signal charge corresponding to the amount of incident light by each photosensor. Is converted to The CCD 58 has a so-called electronic shutter function that controls the charge accumulation time (shutter speed) of each photosensor according to the timing of the shutter gate pulse.
[0030]
The signal charge accumulated in each photosensor is sequentially read out as a voltage signal (image signal) corresponding to the signal charge based on a pulse given from a CCD driver (not shown). The image signal output from the CCD 58 is sent to the analog signal processing unit 60. The analog signal processing unit 60 includes signal processing circuits such as a sampling hold circuit, a color separation circuit, and a gain adjustment circuit. In the analog signal processing unit 60, correlated double sampling (CDS) processing and R, G, and B colors are included. The signal is subjected to color separation processing, and the signal level adjustment (pre-white balance processing) of each color signal is performed.
[0031]
The signal output from the analog signal processing unit 60 is converted into a digital signal by the A / D converter 62 and then added to the image signal processing circuit 64. The image signal processing circuit 64 is an image processing unit including a luminance / color difference signal generation circuit, a gamma correction circuit, a sharpness correction circuit, a contrast correction circuit, a white balance correction circuit, and the like, and processes an image signal in accordance with a command from the CPU 66.
[0032]
When the captured image is displayed and output, the image data is transferred from the image signal processing circuit 64 to the image reproduction processing circuit 70 via the bus 68, and is transmitted through the image reproduction processing circuit 70 and the video encoding circuit 72 in a predetermined manner such as the NTSC system. After being converted into a video signal, it is output to the liquid crystal monitor 52.
[0033]
The image data is periodically rewritten by the image signal output from the CCD 58, and the video signal generated from the image data is supplied to the liquid crystal monitor 52, so that the image input via the CCD 58 is real time. Is displayed. The photographer can check the angle of view by using the image (through image) displayed on the liquid crystal monitor 52 or the viewfinder 36.
[0034]
When the shooting mode is set by the mode dial 38 and the shutter button 22 is pressed, a shooting start instruction (release ON) signal is issued. In response to the receipt of the release ON signal, the CPU 66 starts capturing image data for recording. When the mode for compressing and recording image data is selected, the CPU 66 sends a command to the compression / decompression processing circuit 74. As a result, the compression / decompression processing circuit 74 compresses the image data according to JPEG or another predetermined format.
[0035]
The compressed image data is recorded on a recording medium such as the recording medium 78 via the media control circuit 76. When the mode for recording non-compressed image data (non-compression mode) is selected, the image data is recorded on the recording medium 78 without being compressed without performing the compression processing by the compression / decompression processing circuit 74. The
[0036]
In the camera 10 of this example, for example, smart media (Solid-State Floppy Disk Card) is applied as means for storing image data. The form of the recording medium is not limited to this, and may be a compact flash, a PC card, a magnetic disk, an optical disk, a magneto-optical disk, a memory stick, etc., and read / write according to a method using electronic, magnetic, optical, or a combination thereof. Various possible media can be used. A signal processing means and an interface corresponding to the medium to be used are applied. A configuration in which a plurality of media can be mounted regardless of different types or the same type of recording media may be adopted. The means for storing the image file is not limited to the removable medium that can be attached to and detached from the camera body, but may be a recording medium (internal memory) built in the camera 10.
[0037]
When the movie mode is set by the mode dial 38, moving image recording is possible, the recording operation starts when the shutter button 22 is pressed, and the recording operation stops when the shutter button 22 is pressed again. The recording operation may be performed while the shutter button 22 is continuously pressed, and the recording may be stopped by releasing the pressing. The maximum time, image size, frame rate, and recording method that can be recorded in one shooting are determined in advance. For example, a movie with sound of up to about 80 seconds can be shot in one shooting, 320 x 240 pixels, 10 frames / second, recorded on the recording medium 78 in the Motion JPEG format.
[0038]
When the playback mode is set by the mode dial 38, the image file is read from the recording medium 78 via the media control circuit 84. The compressed data of the read image file is expanded into an uncompressed YC signal via the compression / expansion processing circuit 74.
[0039]
The expanded YC signal is output to the liquid crystal monitor 52 via the image reproduction processing circuit 70 and the video encoding circuit 72. As a result, the last frame image recorded on the recording medium 78 is displayed on the liquid crystal monitor 52.
[0040]
Thereafter, when the right key 42 is pressed, the frame is advanced in the forward direction, and when the left key 40 is pressed, the frame is advanced in the reverse direction. Then, the frame-positioned image file at the frame position is read from the recording medium 78, and the frame image is reproduced on the liquid crystal monitor 52 in the same manner as described above. When the reproduction target file is a moving image file, the first frame of the moving image is displayed as a representative image, and a screen for accepting an instruction to start moving image reproduction is displayed.
[0041]
The CPU 66 is a control unit for overall control of the optical system including the photographing lens 12 and the CCD 58 of the camera system, each signal processing circuit, a recording medium, and the like. The camera 10 stores the program of the CPU 66 in a rewritable manner. A flash ROM 80 is provided. The CPU 66 operates the corresponding circuit based on input signals received from the power switch 24 (corresponding to the switch SW3), the shutter button 22 (corresponding to the switch SW4), the download button 25 (corresponding to the switch SW5) and other operation units. Control, display control on the liquid crystal monitor 52, light emission control of the light emitting diode (LED) 82 such as the finder lamp 37 and the self-timer lamp 20, power control, auto focus (AF) control, automatic exposure (AE) control, and the like. .
[0042]
A control program for the camera 10 is stored in the flash ROM 80. When the camera 10 is turned on and the power is supplied to the CPU 66, a startup program in the flash ROM 80 is executed, and a program in the flash ROM 80 is stored in the DRAM 84. Be expanded. After developing the program in the DRAM 84, the CPU 66 moves the program counter to the program in the DRAM 84 and operates the program on the DRAM 84. The DRAM 84 has an image processing area for storing image data in addition to the program area.
[0043]
The camera 10 of this example can change or add a program in the flash ROM 80. In accordance with a predetermined operation procedure (for example, an operation of connecting the AC power adapter and pressing the download button 25), the camera user reads the change data or the additional data from the recording medium 78, and expands it on the SDRAM 86. Thus, the program can be changed or added by writing to the flash ROM 80.
[0044]
In order to allow the camera 10 to operate normally even if the program is illegally rewritten, such as when the battery is removed during program download or the program writing process to the SDRAM 86 fails. Is provided with a spare flash ROM (hereinafter referred to as a spare flash ROM) 90 that stores a program necessary for the minimum operation of the camera 10. Even if the program rewrite process fails for some reason, the camera can be activated using the program in the spare flash ROM 90. The spare flash ROM 90 is prohibited from being rewritten and the program contents are protected.
[0045]
As a power source of the camera 10, an external power source (hereinafter referred to as an AC power source) connected to the battery or the power input terminal 33 can be used. As the battery, a primary battery or a dedicated secondary battery can be used. The power supplied from the battery or the AC power supply is converted into a required voltage by a power supply circuit 92 including a DC / DC converter, and then supplied to each block.
[0046]
FIG. 4 is a configuration diagram of the power supply circuit 92. As shown in the figure, power is supplied to the CPU 66 from an AC power source or a battery via a DC / DC converter 94. The voltage value of the AC power supply is monitored by the voltage monitoring circuit 95, and information on the detected voltage value of the AC power supply is input to the CPU 66. The voltage value of the battery is monitored by the voltage monitoring circuit 96, and information on the detected battery voltage value is input to the CPU 66.
[0047]
The CPU 66 performs ON / OFF control of the switches SW1 and SW2 based on information received from the voltage monitoring circuits 95 and 96. The switch SW 1 is disposed between the power input terminal 33 and the DC / DC converter 97, and the switch SW 2 is disposed between the positive electrode terminal 98 of the battery and the DC / DC converter 97. It is possible to switch the power supply source to each block (ie, the power supply source to the DC / DC converter 97) by switching the ON / OFF state of both switches SW1 and SW2.
[0048]
Next, the operation of the camera 10 configured as described above will be described. FIG. 5 is a flowchart showing a control procedure of the camera 10. When the camera 10 is powered on by replacing the battery or connecting the AC power adapter, the CPU 66 performs a power-on reset process (step S110) and waits for the switch SW3 corresponding to the power switch 24 to be turned on. (Step S112).
[0049]
When the switch SW3 is turned on, the voltage level of the power input terminal 33 to which the AC power adapter is connected is determined (step S114). If the AC voltage is high (H), the switch SW1 described with reference to FIG. 4 is turned on to use the AC power source as the power source (step S116). On the other hand, if the AC voltage is low (L) in step S114 of FIG. 5, the switch SW2 is turned on to start the camera 10 using the battery as a power source (step S118).
[0050]
Next, the CPU 66 determines whether or not the program in the flash ROM 80 is normal (step S120). In the program stored in the flash ROM 80, a thumb code is also recorded in advance. When the program is activated, a checksum (a kind of error detection method) of the program in the flash ROM 80 is calculated and compared with the recorded sum code to determine whether the program is normal or not.
[0051]
When it is determined in step S120 that the program is normal (YES determination), the CPU 66 develops and executes the program recorded in the flash ROM 80 in the DRAM 84 (step S122), and then switches SW3, SW4, and The monitoring state of SW5 is entered (step S140).
[0052]
On the other hand, if it is determined in step S120 that the program is abnormal, the program in the spare flash ROM 90 is expanded and executed in the DRAM 84 to activate the camera (step S124). In this case, a message “Program is abnormal. Please download a new program” is displayed on the screen of the LCD monitor 52 to prompt the user to download a new program. This message is displayed for a predetermined time (for example, 3 seconds) (step S126), and during this time, the CPU 66 waits for processing (step S128). After the predetermined time has elapsed, the message display is turned off (step S130), and the monitoring state of the switches SW3, SW4, and SW5 is entered (step S140).
[0053]
When any one of the switches SW3, SW4, and SW5 is operated, the switch is determined (step S142), and the process proceeds to a process determined for each switch. That is, when the switch SW3 is operated, the power is turned off to perform the shutdown process (step S144), and the process returns to step S112. When the switch SW4 is operated, the photographing process is executed (step S146), and the process returns to step S140. If switch SW5 is operated, a download process is executed (step S148), and the process returns to step S140.
[0054]
FIG. 6 is a flowchart showing a subroutine of the photographing process. When the shooting process starts, shooting settings such as AE and AF are performed (step S210), and the CCD exposure process is performed based on the settings (step S212).
[0055]
When the CCD exposure is performed, image capture is started (step S214), and predetermined signal processing is executed on the obtained image signal (step S216). Next, after performing data compression processing based on the designated image quality setting (step S218), the data is recorded on the recording medium 78 (step S220).
[0056]
FIG. 7 is a flowchart showing a subroutine of download processing. When the download process starts, the CPU 66 first determines the state of the switch SW1 (step S310). When the switch SW1 is OFF, that is, when the power source is a battery, a message “Please connect the AC power adapter” is displayed on the liquid crystal monitor 52 (step S312), and the download process is stopped. . The message is displayed for a predetermined time (for example, 3 seconds), and during this time, the CPU 66 waits for processing (step S380). After a predetermined time has elapsed, the message is not displayed (step S382), the LED blinking during downloading (in this example, the finder lamp 37 is also used) is turned off (step S384), and this subroutine is exited.
[0057]
On the other hand, when the AC power source is connected and it is detected in step S310 that the switch SW1 is in the ON state, the CPU 66 determines whether or not the recording medium 78 is attached (step S314). The program is downloaded by developing a program stored using a part of the recording area of the recording medium 78 as a program area in the SDRAM 86 and then writing the program in the flash ROM 80. Therefore, if the recording medium 78 is not inserted into the media slot of the camera 10 (NO in step S314), a message “Please insert the recording medium” is displayed on the liquid crystal monitor 52 (step S314). S316), the download is stopped through the above steps S380 to S384.
[0058]
If the recording medium 78 is loaded in step S314 (when YES is determined), the process proceeds to step S318. In step S318, it is detected whether or not program data exists in the recording medium 78. If there is no program in the recording medium 78 (when NO is determined), a message “There is no program in the recording medium” is displayed on the liquid crystal monitor 52 (step S320), and then downloaded through the above steps S380 to S384. Cancel. In this case, the user needs to store a new program in the recording medium 78 using a personal computer (not shown) and then download it again.
[0059]
If there is a program in the recording medium 78 in step S318 (when YES is determined), the download is executed. During the download, a message “Program is being downloaded” is displayed on the liquid crystal monitor 52, and the LED of the finder lamp 37, which is also used as an access lamp, blinks (step S322). This message display and LED blinking notify the user that downloading is in progress. Further, during the download, the CPU 66 disables the input signals from the switches SW3 to SW5 so that the power supply does not stop during the download.
[0060]
Then, the program is transferred from the recording medium 78 to the SDRAM 86, and the program is expanded on the SDRAM 86 (step S324). A thumb code is recorded in the program, and the thumb code is copied to the SDRAM 86 together with the program. After the program is expanded in the SDRAM 86, a checksum of the expanded program is calculated and compared with a prerecorded sum code to determine whether or not the program on the SDRAM 86 is normal (step S326). .
[0061]
If the sum codes do not match, a message “Program is abnormal” is displayed on the liquid crystal monitor 52 (step S328), and the download is stopped through steps S380 to S384.
[0062]
In step S326, if the thumb codes match and it is determined that the program is normal, the process proceeds to step S330, the counter count value i is initialized (i = 0), and the SDRAM 86 transfers to the flash ROM 80. The program is written (step S332). After the writing of the program to the flash ROM 80 is completed, a checksum of the rewritten program is calculated and checked against the sum code to determine whether the program on the flash ROM 80 is normal (step S334).
[0063]
If the thumb codes match in step S334, “download complete” is displayed on the liquid crystal monitor 52 (step S336), and the download process is terminated through steps S380 to S384.
[0064]
On the other hand, if the sum codes do not match in step S334 and it is determined that the program is abnormal, the process proceeds to step S338, and the counter is incremented by +1. Next, it is determined whether or not the count value i has exceeded a predetermined number of times N set in advance (step S340). If the number of times N has not been exceeded (when NO is determined), the process returns to step S332. In this way, “write” and “check” are repeated for the specified number of times N. If the program is normally written in the process (YES in step S334), the download is completed (steps S380 to S384).
[0065]
If the same number of times N is tried and “write” is attempted, but the sum code does not match until the end, a message “Download failed. Repair is required” is displayed on the LCD monitor 52 (step S342). The download process is terminated through the above steps S380 to S384. In this case, since there is a high possibility that the hardware of the camera 10 has failed, a recommendation is made to urge the user to request a repair from the manufacturer. Even if the download fails, the camera 10 can be activated and can be shot using the program in the spare flash ROM 90.
[0066]
FIG. 8 is a flowchart of the AC power supply instantaneous stop interrupt process. As described in FIG. 4, the voltage of the AC power source is monitored by the voltage monitoring circuit 95, and the voltage of the AC power source rapidly decreases during the download described in steps S322 to S324 in FIG. When the specified voltage value is exceeded, an interrupt occurs. When the CPU 66 detects an interrupt signal, the interrupt process shown in FIG. 8 starts. That is, when the CPU 66 detects an interrupt signal, the battery voltage is checked (step S410). If the voltage is high (H), the switch SW1 described in FIG. 4 is turned off and the switch SW2 is turned on. Then, the power supply source is switched to the battery side and the download process is continued (S412).
[0067]
On the other hand, if the battery voltage is low (L) in step S410, it is shut down (step S414) and the program is stopped. At the time of download, the AC power adapter is required to be used. If the AC power adapter is disconnected during the download, check the voltage of the battery, and if it is available, use the power source as a battery. By switching to, download failure is avoided.
[0068]
Next, a modified example of the above-described embodiment will be described. In FIG. 3, the contents of the flash ROM 80 are rewritable, and the spare flash ROM 90 storing the program necessary for the minimum operation of the camera 10 is not rewritten. However, the contents of the spare flash ROM 90 can also be updated. There is also an aspect configured as follows.
[0069]
FIG. 9 is a block diagram showing another embodiment of the present invention. In the figure, parts common to those in the block diagram shown in FIG. The camera 10 shown in FIG. 9 has a flash ROM (A) 81 and a flash ROM (B) 91 as means for holding a control program, and is configured so that the roles of both can be switched.
[0070]
It is assumed that a code (bit) for identifying which of the flash ROM (A) 81 and the flash ROM (B) 91 is developed in the DRAM 84 is prepared in the flash ROM (A) 81. For example, when shipped from the factory, the flash ROM (B) 91 is set as a spare flash ROM. In this case, information of “flash ROM selection bit = ON” is written in the flash ROM (A) 81, and the program is expanded from the flash ROM (A) to the DRAM 84 when the camera is activated. For the flash ROM (B) 91 assigned as a spare flash ROM, a control program equivalent to the flash ROM (A) 81 may be stored at the time of shipment from the factory, or a control program may be stored. It does not have to be.
[0071]
When the program is rewritten (downloaded) by the camera 10, a new program is written in the flash ROM (B) 91, and the flash ROM (A) functions as a spare flash ROM while retaining the old program. At this time, the flash ROM selection bit is changed to OFF.
[0072]
Thereafter, the program of the flash ROM (B) 91 is expanded in the DRAM 84 when the camera is activated, and camera control is performed. Even if the download is unsuccessful, the camera 10 can be activated by an old program (a program with an operation record) stored in the flash ROM (A) 81. The rewriting of the program is performed on the flash ROM on the spare side, and the roles of the flash ROM (A) 81 and the flash ROM (B) 91 are alternately switched for each rewriting.
[0073]
Flow charts relating to the control of the camera 10 shown in FIG. 9 are shown in FIGS. In these drawings, the same steps as those in the flowcharts of FIGS. 6 and 7 are denoted by the same step numbers and the description thereof is omitted.
[0074]
After the power source is selected in step S116 or S118 of FIG. 10, the process proceeds to step S130, and the state of the flash ROM selection bit is determined. If the flash ROM selection bit is ON, the process proceeds to step S132, and the program of the flash ROM (A) 81 is expanded and executed in the DRAM 84. On the other hand, if the flash ROM selection bit is OFF in step S130, the program in the flash ROM (B) 91 is expanded and executed in the DRAM 84 (step S134).
[0075]
After step S132 or step S134, the process proceeds to step S140. Subsequent processing is as described in FIG.
[0076]
The download processing subroutine shown in step S148 of FIG. 10 is shown in FIGS. After the counter is initialized (i = 0) in step S330 in FIG. 12, the process proceeds to step S342. In step S342, the state of the flash ROM selection bit is determined. If the flash ROM selection bit is ON, that is, if the program in the flash ROM (A) 81 is currently being developed and executed in the DRAM 84, the process proceeds to step S344, and the new program in the SDRAM 86 is written in the flash ROM (B) 91. Execute the process. After writing the program to the flash ROM (B) 91, the checksum of the rewritten program is calculated and checked against the sum code to determine whether the program on the flash ROM (B) 91 is normal. This is performed (step S346).
[0077]
If the thumb codes match in step S346, the flash ROM selection bit is reversed (OFF if ON, changed to ON if OFF) (step S370), and a message “Download complete” is displayed on the LCD monitor 52 ( After step S372) and steps S380 to S384, the download process is terminated.
[0078]
On the other hand, if the sum codes do not match in step S346 and it is determined that the program is abnormal, the process proceeds to step S348, and the counter is incremented by +1. Next, it is determined whether or not the count value i has exceeded a preset specified number N (step S350). If the count value i has not exceeded the specified number N (NO determination), the process returns to step S344. In this way, “write” and “check” are repeated for the specified number of times N. If the program is normally written in the process (YES in step S346), the download is completed (steps S370 to S384).
[0079]
If the same number of times N is tried and “write” is attempted but the sum code does not match until the end, the message “Download failed. Repair is required” is displayed on the LCD monitor 52 (step S352). The download process is terminated through steps S380 to S384. Even if the download fails, the camera 10 can be activated by using the program of the flash ROM (A) 81 that has been used so far, and photographing can be performed.
[0080]
In step S342, if the flash ROM selection bit is OFF, that is, if the program in the flash ROM (B) 91 is currently expanded and executed in the DRAM 84, the process proceeds to step S354, and the new program in the SDRAM 86 is transferred to the flash ROM (A ) The process of writing to 81 is executed. After writing the program to the flash ROM (A) 81, the checksum of the rewritten program is calculated and checked against the sum code to determine whether the program on the flash ROM (A) 81 is normal. This is performed (step S356).
[0081]
If the thumb codes match in step S356, the flash ROM selection bit is inverted (step S370), a message “download complete” is displayed on the liquid crystal monitor 52 (step S372), and the download process is terminated through steps S380 to S384. To do.
[0082]
On the other hand, if it is determined in step S356 that the sum codes do not match and it is determined that the program is abnormal, the process proceeds to step S358, the counter is incremented by +1, and “write” and “check” are repeated for the specified number of times N. If the program is normally written in this process (YES in step S356), the download is completed (steps S370 to S384).
[0083]
If the same number of times N is tried and “write” is attempted, but the sum code does not match, the message “Download failed. Repair is required” is displayed on the LCD monitor 52 (step S362). The download process is terminated through steps S380 to S384. Even if the download fails, the camera 10 can be activated by using the program of the flash ROM (B) 91 that has been used so far, and the image can be taken.
[0084]
Conventionally, since there is no means for storing a spare program, if the program writing to the flash ROM fails, the program in the DRAM is normal and no malfunction occurs, but the power is turned off once. When the power is turned on again, an illegal program is developed and executed in the DRAM, so that the operation of the camera becomes defective and the program cannot be rewritten (re-downloading). there were.
[0085]
In contrast, the camera according to the embodiment of the present invention requires the use of an AC power adapter at the time of download, and even if the AC power adapter is removed, the power source is automatically switched to the battery and the download is continued. In addition to being equipped with functions that prevent download interruptions, the camera can no longer operate because it is configured to be able to start up with a spare program even if program rewriting fails. Can be avoided. Thereby, the control program can be easily and reliably updated (version upgrade).
[0086]
In the above embodiment, the digital camera has been described as an example. However, the scope of application of the present invention is not limited to this, and the present invention can be applied to various electronic devices such as portable information terminals, audio devices, and image playback devices. It is.
[0087]
【The invention's effect】
As described above, the electron according to the present invention camera Since the program rewrite operation is prohibited when the battery is driven, it is possible to avoid a download failure due to battery consumption during rewriting. In addition, the power switch is disabled during download to prevent the power from being turned off, or when the voltage of the external power supply drops, the power supply source is switched to the battery side to ensure power supply to avoid interruption of the download. it can.
[0088]
Further, the electronic of the present invention camera Since it has a spare memory that holds a spare program, the device can be started up by the spare program even if the program rewrite fails and the program is changed to an illegal program.
[Brief description of the drawings]
FIG. 1 is a perspective view of a digital camera according to an embodiment of the present invention.
FIG. 2 is a rear view of the camera shown in FIG.
FIG. 3 is a block diagram showing a configuration of a digital camera according to the present embodiment.
4 is a configuration diagram of the power supply circuit shown in FIG. 3;
FIG. 5 is a flowchart showing a control procedure of the camera of this example.
FIG. 6 is a flowchart showing a control procedure of imaging processing.
FIG. 7 is a flowchart showing the procedure of download processing.
FIG. 8 is a flowchart showing interrupt processing relating to power supply switching;
FIG. 9 is a block diagram showing the configuration of a digital camera according to another embodiment of the present invention.
10 is a flowchart showing a control procedure of the camera shown in FIG. 9;
FIG. 11 is a flowchart showing a procedure of download processing of the camera shown in FIG. 9;
12 is a flowchart showing a procedure of download processing of the camera shown in FIG. 9;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Camera (electronic device, electronic camera), 12 ... Shooting lens, 24 ... Power switch, 33 ... Power input terminal (external power input means), 58 ... CCD (imaging means), 66 ... CPU (control circuit, prohibition means) , Power supply switching means, confirmation means), 76... Media control circuit (recording means), 78... Recording medium (program providing means, recording medium), 80... Flash ROM (program memory), 90. ), 95... Voltage monitoring circuit (voltage monitoring means), SW1, SW2... Switch (power supply switching means)

Claims (4)

An electronic camera comprising: an imaging unit that converts an optical image into an electrical signal; and a recording unit that records image data acquired via the imaging unit on a predetermined recording medium,
A control circuit for controlling the operation of the electronic camera ;
A program memory for holding a rewritable program that defines the processing steps of the control circuit;
An external power input means capable power supply from the outside of the electronic camera,
Instead of the power supplied from the external power supply input means, a battery that can be a power supply source,
A recording medium mounting means, wherein the recording medium is detachably mounted,
A spare program memory for prescribing the processing steps of the control circuit, and a spare program memory in which rewriting of the spare program is prohibited;
It is determined whether or not electric power is supplied from the outside of the electronic camera , and whether or not the recording medium is mounted on the recording medium mounting means, and is supplied with power from the outside and the recording medium mounting means If it is determined that the recording medium is mounted on the recording medium, the recording medium is stored using a part of the recording area of the recording medium while turning on or blinking the finder lamp or the self-timer lamp The program is read and the program is downloaded to the program memory while downloading is performed, or when it is determined that power is supplied from the battery, or the recording medium mounting means determines that the recording medium is not mounted A download means that does not perform the download,
Wherein said control circuit, when failed in the downloading, an electronic camera, characterized in that to start the electronic camera by using the preliminary program rewritten to the preliminary program memory are stored is prohibited. An instruction means for instructing the start of the download;
The download unit performs control to present a warning requesting connection of an external power source when power is supplied from the battery when the start of the download is instructed from the instruction unit. The electronic camera according to claim 1. The control circuit performs control for invalidating an instruction from a power switch of the electronic camera and maintaining a power supply state during an operation of writing the program from the recording medium to the program memory. Item 3. The electronic camera according to Item 1 or 2. Voltage monitoring means for monitoring the power supply voltage supplied from the external power input means;
Power supply switching means for switching the power supply source to the battery when the power supply voltage drops below a predetermined value during the operation of writing the program from the recording medium to the program memory;
The electronic camera according to any one of claims 1 to 3, further comprising:

Images