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Claims  |
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What is claimed is:
1. A digital electronic still video camera to which a memory cartridge is
connected in a loadable/unloadable manner, the memory cartridge storing,
in the form of digital data, a video signal representing a still picture,
the camera comprising:
connecting means to which the memory cartridge is electrically connected in
a loadable/unloadable manner;
image pick-up means, having a solid-state image pick-up device, for imaging
light of a subject received by said solid-state image pick-up device and
for outputting a video signal representing the subject;
signal converting means for converting the video signal outputted by said
image pick-up means into a corresponding digital signal and for outputting
the digital signal to said connecting means; and
control means for controlling said image pick-up means to perform imaging
and said signal converting means to convert the outputted video signal
into the digital signal, and for supplying said connecting means with a
control signal for controlling writing into the memory cartridge, said
control means comprising
information generation means for generating information for verifying that
the memory cartridge has been electrically connected to the camera through
said connecting means, and
information verifying means for verifying the information generated,
said control means transmitting the information generated by said
information generating means to the memory cartridge for storage therein,
reading the stored information from the memory cartridge, and enabling
each functional part of the camera to perform a photographic operation
after said information verifying means verifies that the generated
information is identical to the stored information read from the memory
cartridge.
2. A digital electronic still video camera to which a memory cartridge is
connected in a loadable/unloadable manner, the memory cartridge storing,
in the form of digital data, a video signal representing a still picture,
the camera comprising:
connecting means to which the memory cartridge is electrically connected in
a loadable/unloadable manner;
image pick-up means, having a solid-state image pick-up device, for imaging
light of a subject received by said solid-state image pick-up device and
for outputting a video signal representing the subject;
signal converting means for converting the video signal outputted by said
image pick-up means into a corresponding digital signal and for outputting
the digital signal to said connecting means; and
control means for controlling said image pick-up means to perform imaging
and said signal converting means to convert the outputted video signal
into said corresponding digital signal, and for supplying said connecting
means with a control signal for controlling writing into the memory
cartridge, said control means comprising
information generation means for generating information for verifying that
the memory cartridge has been electrically connected to the camera through
said connecting means, the information generated being a checking code
having a number of bits equivalent to a number of data input/output
terminals of the camera, and
information verifying means for verifying the information generated,
said control means sending the information generated by said information
generating means to the memory cartridge and enabling each functional part
of the camera to perform a photographic operation after said information
verifying means verifies that the generated information has been stored in
the memory cartridge, after the memory cartridge is loaded in the camera.
3. The camera according to claim 1, wherein the information generated by
said information generating means includes information directing playback
of the still picture stored in the memory cartridge.
4. The camera according to claim 1, further comprising:
loading sensing means for sensing that the memory cartridge has been loaded
in the camera, said loading sensing means supplying electrical power from
a power supply means of the camera to said control means to thereby enable
operation of said control means upon sensing that the memory cartridge has
been loaded in the camera.
5. A digital electronic still video camera to which a memory cartridge is
connected in a loadable/unloadable manner, the memory cartridge storing,
in he form of digital data, a video signal representing a still picture,
the camera comprising:
connecting means to which the memory cartridge is electrically connected in
a loadable/unloadable manner;
image pick-up means, having a solid-state image pick-up device, for imaging
light of a subject received by said solid-state image pick-up device and
for outputting a video signal representing the subject;
signal converting means for converting the video signal outputted by said
image pick-up means into a corresponding digital signal and for outputting
the digital signal to said connecting means; and
control means for controlling said image pick-up means to perform imaging
and said signal converting means to convert the outputted video signal
into the digital signal, and for supplying said connecting means with a
control signal for controlling writing into the memory cartridge, said
control means
generating information, in information generating means, for verifying that
the memory cartridge has been electrically connected to the camera through
said connecting means,
transmitting the generated information to the memory cartridge for storage
therein,
reading the generated information stored within the memory cartridge,
verifying, in information verifying means, if the generated information is
identical to the stored generated information read from the memory
cartridge, and
enabling each functional part of the camera to perform a photographic
operation when said information verifying means verifies that the
generated information is identical to the stored information read from the
memory cartridge.
6. The camera according to claim 5, wherein the information generated by
said information generating means is a checking code having a number of
bits equivalent to a number of data input/output terminals of the camera.
7. The camera according to claim 5, wherein the information generated by
said information generating means includes information directing playback
of the still picture stored in the memory cartridge.
8. The camera according to claim 5, further comprising:
loading sensing means for sensing that the memory cartridge has been loaded
in the camera, said loading sensing means supplying electrical power from
a power supply means of the camera to said control means to thereby enable
operation of said control means upon sensing that the memory cartridge has
been loaded in the camera.
9. A method of verifying electrical connection of a loadable memory
cartridge and a camera connectable through a plurality of terminal pairs
comprising the steps of:
transmitting to the memory cartridge through the plurality of terminal
pairs, under direction of control means, generated information for storage
within a specific memory address of the memory cartridge;
reading the stored generated information from the specific memory address;
comparing the generated information and the stored generated information,
in a comparison means, to determine coincidence thereof; and
generating a signal indicative of coincidence and verification of
electrical connection of the camera and the memory cartridge through the
plurality of terminal pairs.
10. The method of verifying electrical connection of a loadable memory
cartridge and a camera of claim 9 comprising the further steps of:
transmitting to the memory cartridge newly generated information, different
than the generated information, for storage in the specific memory address
of the memory cartridge upon determination of non-coincidence of the
generated information and the stored generated information; and
repeating said comparing and generating steps using the newly generated
information to determine coincidence.
11. The method of verifying electrical connection of a loadable memory
cartridge and a camera of claim 9, comprising the further steps of:
transmitting to the memory cartridge the generated information for storage
in a second specific memory address, different than the specific memory
address, of the memory cartridge upon determination of non-coincidence of
the generated information and the stored information of the specific
memory address; and
repeating said comparing and generating steps using the generated
information of the second specific address to determine coincidence.
12. A camera electrically connectable to a loadable memory cartridge
through a plurality of terminal pairs, the memory cartridge storing, in
the form of digital data a signal representing a picture, the camera
comprising:
detection means for detecting loading of the memory cartridge into the
camera and for providing power to the camera upon detection;
transmitting means, operable under direction of control means, for
transmitting to the memory cartridge through the plurality of terminal
pairs information from said control means for storage therein in a
specific memory address upon receipt of power to the camera;
reading means for reading out the information stored in said specific
memory address; and
electrical connection verification means, coupled to said control means and
said reading means, for comparing and determining coincidence between the
information and stored information to generate a signal as a result of
coincidence indicative of electrical connection between the camera and
memory cartridge through said plurality of terminal pairs.
13. The camera of claim 12, said detection means comprising:
power source means for providing power for the camera;
a power supply switch, coupled to said power source means and control
means, for providing power from said power source means to said control
means, and the camera, upon activation thereof; and
an inversion gate, coupled to a first terminal of a first pair of said
plurality of terminal pairs within the camera, for providing a power
supply signal to turn on said power supply switch directing supply of
power to said control means and camera,
a first terminal of a second pair of said plurality of terminal pairs
coupled to a ground potential of said power source means within the
camera, and second terminals of said first and second pairs of said
plurality of terminal pairs coupled together within the memory cartridge,
the ground potential of said first terminal of said second pair incident
upon said first terminal o said first pair, and said inversion gate, upon
loading of the memory cartridge within the camera to provide the power
supply signal to said power supply switch.
14. The camera of claim 12, said camera a digital electronic still video
camera and said digital data representing a still picture. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
This invention relates to an electronic device, such as an electronic still
video camera, which, on the basis of a physical signal (such as an
electric signal, magnetic signal or optical signal ), is capable of being
coupled to a memory cartridge when the cartridge is loaded in the device
at a predetermined location thereof. The electronic still video camera
mentioned here refers to a camera which stores a video signal representing
a still picture in a memory device in the form of digital data.
Attempts have been made to develop IC cards, CPU cards and memory cards,
which incorporate an internal semiconductor element such as an IC or a
semiconductor device, for use in a wide variety of fields as a substitute
for conventional magnetic cards, a substitute for external memories such
as floppy discs, and as novel electronic media or control means. Some of
these cards have been put into practical use. When such a card is loaded
in a prescribed location of an automatic machine, control device or other
electronic device, the device and the card are rendered connectable by a
physical signal, such as an electric signal, magnetic signal or optical
signal. More specifically, connection terminals on the card can be
connected to a connector on the side of the electronic device, or coupling
can be achieved magnetically or optically. Under these conditions, the
electronic device and the card can communicate with each other and the
electronic device can execute card processing, such as writing data in the
memory of the card.
In general, an IC card, a CPU card and a memory card are physically handled
and, as a result, the connection terminals tend to pick up grease, dust
and other foreign matter, which can lead to a poor connection. When the
connection terminals do not make good contact with the connector of the
electronic device, the aforementioned card processing cannot take place
normally. In other words, a faulty connection can cause errors to appear
in the communications between the electronic device and the card and can
make it impossible to write data into the memory of card correctly.
One conceivable application of a memory card having a comparatively
large-capacity memory is as a medium for storing image data picked up by a
digital electronic still video camera. Since a camera of this kind can be
used outdoors as well as indoors, the connection terminals of the memory
card easily pick up moisture and therefore tend to oxidize and corrode.
This is a cause of faulty connections, which can make correct recording of
video data impossible. A memory card provided with a very large memory
capacity will predictably have a large number of connection terminals.
Since reliable recording cannot be expected even if only one of these
terminals develops a faulty connection, there is greater risk of recording
failure.
The adherence of dust or other contaminants can lead to a faulty connection
not only in instances where coupling depends upon the electrical contact
between the connection terminals of the card and the connector of the
electronic device but also in cases where coupling is achieved
magnetically or optically.
Correct card processing also cannot be expected if the loading (as by
insertion) of the card into the electronic device is not performed in the
proper manner.
The special circumstances concerning an electronic still video camera will
now be described in detail.
An electronic still video camera described in the specification of Japanese
Patent Application Laid-Open (KOKAI) No. 59-183592 includes a camera body
having an imaging optical system and a solid-state image pick-up device
and is connected to a loadable/unloadable memory which stores, in the form
of a digital signal, a video signal representing a still picture imaged by
the image pick-up device. The memory storing the video signal is removed
from the camera and loaded in a playback apparatus. The playback apparatus
reads the video signal out of the memory and reproduces the video signal
as a visible picture on the screen of a video monitor.
When photography is performed using an electronic still video camera of
this type, it is necessary to load the memory in the camera accurately in
order to connect the memory to the camera circuit-wise, after which
photography is performed to produce a video signal which is then stored in
the memory. However, since the electrical circuit-wise connection of the
memory cannot be detected in this conventional electronic still video
camera, it is impossible for the operator to know at the time that the
memory is loaded whether the memory has actually been connected to the
camera in terms of the electrical circuitry. If the connection has not
been made, therefore, a video signal will not be stored in the memory even
if the photographer takes a picture of a subject. This means that the
photographer will have wasted his time since the picture which should have
been taken will not be recorded.
Furthermore, in spite of the fact that the video signal is not being stored
in the memory, the electronic still video camera will nevertheless image
the subject being shot, convert the resulting video signal into a digital
signal, create color separation information, optical distortion
information and various types of data necessary for playback on a playback
apparatus, and deliver these signals and data to connection means. Power
is thus consumed wastefully.
SUMMARY OF THE INVENTION
An object of the present invention is to make it possible to check the
coupling between an electronic device and e.g. an IC card, a CPU card
having a memory, a memory card or a semiconductor memory module (referred
to generally as "memory cartridges") by comparatively simple processing.
Another object of the present invention is to provide a signal electronic
still video camera capable of performing photographic operations only
after a memory cartridge has been positively connected to the camera and
video signals are capable of being recorded.
The present invention provides an electronic device which, when a memory
cartridge having a memory is loaded in the electronic device, is capable
of coupling with the memory cartridge based on a physical signal, the
electronic device comprising first sensing means for sensing that the
memory cartridge has been loaded at a prescribed location in the
electronic device, writing means for designating a predetermined address
in the memory of the memory cartridge and writing a predetermined code at
the predetermined address when loading of the memory cartridge has been
sensed by the first sensing means, reading means for reading the code
written by the writing means out of the memory, and second sensing means
for sensing coincidence between the code written by the writing means and
the code read by the reading means.
When coincidence is not sensed, this means that coupling is faulty. In a
preferred embodiment, therefore, means are provided for outputting a
warning signal when coincidence is not sensed.
In a preferred embodiment, the aforementioned writing, reading and
coincidence sensing processing is executed a number of times changing the
address or the code or both.
The memory cartridge refers to an arrangement in which the memory is housed
in a case such as a card-shaped case or box-shaped case, as well as to a
semiconductor memory module. It goes without saying that the concept of a
memory cartridge covers not only one having a CPU and a memory and one
further including a liquid crystal display device and a keyboard, but also
one having only a memory and no CPU or one having a required power supply
and some other circuitry in addition to a memory. Furthermore, as
mentioned above, the type of coupling between the memory cartridge and the
electronic device includes not only electrical contact between the
connection terminals of the memory cartridge and the connector of the
electronic device but also optical coupling, which comprises one or a
plurality of light-projecting elements provided on one of the memory
cartridge and electronic device and one or a plurality of light-receiving
elements provided on the other of the memory cartridge and electronic
device, and magnetic coupling, comprising coil means or the like.
In accordance with the invention, a predetermined code from the electronic
device is transmitted to the memory cartridge through the aforementioned
physical coupling and the code is written in the memory. The code that has
been written in the memory is read by the electronic device, and it i
determined whether the read code coincides with the written code. If
coincidence is detected, then a decision is rendered that the physical
coupling is normal. If coincidence is not detected, however, the decision
rendered is that the physical coupling is abnormal.
Thus, processing for determining whether or not the memory cartridge and
electronic device are coupled normally can be performed after a
comparatively short period of time and in a comparatively simple manner.
A device for checking the state of coupling between a memory cartridge and
an electronic device in accordance with the invention comprises a memory
cartridge having a memory and first coupling means, and an electronic
device having a second coupling means, wherein when the memory cartridge
is loaded in the electronic device, the electronic device is capable of
being coupled with the memory cartridge through the first and second
coupling means on the basis of a physical signal.
The memory cartridge is provided with means for generating a checking code,
and changeover means for changing over a connection between the first
coupling means and the memory or the checking code generating means.
One of the memory cartridge and the electronic device is provided with
means for sensing that the memory cartridge has been loaded in the
electronic device at a predetermined location thereof, and control means
for controlling the changeover means in such a manner that the checking
code generating means is connected to the first coupling means when
loading of the memory cartridge in the electronic device has been sensed.
The electronic device is provided with means for examining the checking
code transmitted by the checking code generating means via the first and
second coupling means, and for determining whether coupling performed by
the first and second coupling means normal or abnormal.
In accordance with the invention, when the memory cartridge is loaded in
the electronic device, the predetermined code generated in the memory
cartridge is transferred to the electronic device through the first and
second coupling means, and the electronic device examines the code to
determine if it is the predetermined one. If this is determined to be the
fact, the electronic device decides that the coupling between it and the
memory cartridge is normal. If non-coincidence is detected, the electronic
device decides that the coupling is abnormal.
Thus, processing for determining whether or not the memory cartridge and
electronic device are coupled normally can be performed after a
comparatively short period of time and in a comparatively simple manner.
Further, in accordance with the invention, there is provided a digital
electronic still video camera to which a memory cartridge is connected in
a loadable/unloadable manner, the memory cartridge storing, in the form of
digital data, a video signal representing a still picture, the camera
comprising: connecting means to which the memory cartridge is connected
circuit-wise in a loadable/unloadable manner; image pick-up means having a
solid-state image pick-up device and adapted to image a subject by the
solid-state image pick-up device and output a video signal representing
the subject; signal converting means for converting the video signal
outputted by the image pick-up means into a corresponding digital signal
and outputting the digital signal to the connecting means; and control
means for controlling the image pick-up means and signal converting means
to cause the image pick-up means to perform imaging and cause the signal
converting means to convert the outputted video signal into a digital
signal, and for supplying the connecting means with a control signal for
controlling writing into the memory cartridge; the control means including
information generating means for generating information for verifying that
the memory cartridge has been connected to the camera electrical
circuit-wise by the connecting means, and information verifying means for
verifying the information generated; wherein when the memory cartridge is
loaded in the camera, the control means sends the information generated by
the information generating means to the memory cartridge, and enables each
functional part of the camera to perform a photographic operation after
the information verifying means verifies that the information has been
stored in the memory cartridge.
Thus, in accordance with the invention, power is not supplied when loading
of the memory cartridge is not sensed. This makes it possible to prevent
photographic errors due to a faulty connection between the memory
cartridge and the camera. Furthermore, a code for checking the connection
to the memory cartridge is written in the memory, and photography is made
possible after sensing that this information has been written in the
memory. This prevents the occurrence of a situation in which a video
signal cannot be recorded in the memory. Wasteful consumption of power can
therefore be avoided.
Since photography is made possible only after information necessary for
playback is written in the memory beforehand, it is possible to avoid a
situation in which the information necessary for playback is not stored in
the memory.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an embodiment of the present invention and shows the
state of a connection between an electronic device and a memory cartridge,
as well as the electrical construction of the device and cartridge;
FIG. 2 is a flowchart illustrating a connection checking processing
procedure;
FIG. 3 is a view showing another example of sensing loading of a memory
cartridge;
FIG. 4 illustrates another embodiment of the present invention and shows
the state of a connection between an electronic device and a memory
cartridge, as well as the electrical construction of the device and
cartridge;
FIG. 5 is a functional block diagram illustrating yet another embodiment of
the present invention and showing a digital electronic still video camera;
FIG. 6 is a circuit diagram illustrating a specific example of a connection
sensing circuit included in the arrangement of FIG. 5;
FIG. 7 is a circuit diagram illustrating another example of the connection
sensing circuit; and
FIG. 8 is a functional block diagram illustrating an exemplary arrangement
of a playback apparatus which plays back a video signal stored in a memory
by the camera embodied in FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates the state of a connection between an electronic control
device 10 and a memory cartridge 20.
The electronic device 10 is a device, such as a digital electronic still
video camera, which requires the memory cartridge 20 as a medium for
storing desired data. The electronic device 10 is provided with a recess
or guide 15 in which the memory cartridge 20 is loaded, as by being
inserted. The portion of the memory cartridge 20 that is inserted into the
recess 15 is formed to have a number of connection terminals 24. Provided
in the recess 15 of the electronic device 10 is a connector 14 having
terminals equivalent in number to the terminals 24 for electrically
contacting these terminals when the memory cartridge 20 is loaded. Also
disposed in the recess 15 is a limit switch 16 for sensing that the memory
cartridge 20 has been loaded in the recess 15 in proper fashion. The limit
switch 16 produces a detection signal applied to a CPU 11. It is possible
to sense the loading of the memory cartridge 20 by any of a variety
ofsensors, such as a photoelectric switch for sensing loading optically,
or a switch for sensing loading magnetically. It is possible to sense
loading of the memory cartridge 20 by electrical sensing means such as
shown in FIG. 3. One terminal 14a of the connector 14 of electronic device
10 is connected to the ground of the electronic device, and one other
terminal 14b of the connector 14 is connected to the CPU 11 through an
amplifier if necessary. Terminals 24a, 24b of the memory cartridge 20 that
are to be connected to respective ones of the terminals 14a, 14b are
connected to each other and to the ground of the memory cartridge. When
the memory cartridge 20 is loaded in the electronic device 10,
ground-level signals are applied to the CPU 11 through the terminals 14a,
24a, 24b, 14b. The CPU 11 is thus capable of sensing that the memory
cartridge 20 has been loaded.
The electronic device 10 is provided with the abovementioned CPU 11, which
controls various operations in the electronic device and executes
processing, described below, to check the connection of the memory
cartridge. The electronic device 10 is also provided with an alarm device
19, such as a buzzer or light-emitting diode, which informs an operator of
the fact that the checked connection has been determined to be faulty when
such a determination is made. The alarm device 19 is connected to the CPU
11.
The memory cartridge 20 has several internal memory chips 21. If volatile,
these memories incorporate a power supply such as a battery.
Some of the terminals of connector 14 and the corresponding connection
terminals 24 of memory cartridge 20 are for transmitting an address signal
used to address the memory in the memory cartridge 20. Some of the other
of these terminals are for transferring data. Furthermore, one or a
plurality of the terminals is for transmitting a chip-select signal CS,
and one or a plurality is a terminal for a read/write command R/W from the
CPU 11. These terminals in connector 14 are connected to the CPU 11 by an
address bus, data bus and control lines for the signals CS, R/W. The
terminals 24 of memory cartridge 20 are also connected to respective ones
of the address bus, data bus and control lines connected to the memory
chips 21. Accordingly, when the memory cartridge 20 is loaded in the
electronic device 10, the address bus, data bus and control lines inside
the electronic device 10 are connected to the corresponding buses and
lines in the memory cartridge 20 via the connector 14 and terminals 24,
and it becomes possible for the CPU 11 of electronic device 10 to directly
access the memory of the memory cartridge 20.
Depending upon the particular case, a connection terminal is also provided
in order to connect a power supply line for the purpose of supplying the
memory cartridge 20 with electric power from the electronic device 10.
FIG. 2 shows the general features of a connection checking processing
executed by the CPU 11.
When the limit switch 16 issues a detection signal indicating that the
memory cartridge 20 has been loaded at step 101, the CPU 11 outputs an
address signal, which designates a predetermined address of the memory in
memory cartridge 20, as well as the chip select signal, sends a
predetermined code out on the data bus, and outputs a write command (step
102). As a result, the abovementioned code is written in the designated
storage location of the memory in memory cartridge 20. Next, the CPU 11
outputs an address signal designating the same address as mentioned above,
a chip-select signal and a read command, and reads the previously written
code out of the same storage location through the data bus (step 103). The
CPU 11 compares the code that was transmitted for the purpose of being
written and the code read in response to the read command, and determines
whether the two codes coincide (step 104). If the two codes coincide, the
same processing is repeated upon altering at least the address or the code
data (step 105). When writing, reading and comparing processing regarding
combinations of given addresses and codes ends, connection checking
processing is terminated and the program proceeds to predetermined
processing relating to the memory cartridge 20, e.g. to processing for
writing video data in a predetermined memory area. If the two codes are
found not to coincide at the step 104, a command is applied to the alarm
device 19, which responds by issuing an alarm indicative of
non-coincidence (step 106).
By way of example, in the first cycle of processing, a signal composed of
all 0's (i.e. a signal in which all bits are zero) is applied as an
address signal (inclusive of the chip-select signal), and data in which 1
and 0 repeat alternatingly starting from 1, as in the manner 1010 . . .,
is applied as a code. The checking processing of steps 102 through 104 is
executed based on this address signal and code. In the second cycle of
processing, an address signal composed of all 1's and data 0101 . . ., in
which the code is reversed, are applied and the processing of steps 102
through 104 is executed in the same manner. By adopting such an
arrangement, 1 and 0 signals are transmitted through all terminals of
connector 14 and all of the corresponding connection terminals 24 in at
least two processing cycles. Accordingly, if a YES decision (coincidence)
is rendered at the step 104 in each of these processing cycles, then this
will mean that all of the terminals are in a satisfactorily connected
state.
It goes without saying that the combinations of address signals and codes
given by the CPU 11 can be selected at will.
If necessary, an arrangement can be adopted in which, when a NO answer is
received at the step 104, thereby indicating that the connection is
faulty, the program proceeds to warning processing only if a YES answer
still is not received even after the processing for designating the same
address, transmitting the same code and reading out the code is repeated a
predetermined number of times. In a configuration having an automatic
loading mechanism which loads the memory cartridge automatically, it can
be arranged so that the memory cartridge is ejected once and then reloaded
when a NO answer is received at the step 104.
FIG. 4 illustrates another embodiment of the invention. Portions in FIG. 4
which are identical with those of FIG. 1 or which implement the same
functions are designated by like reference characters and are not
described again.
In this embodiment, the electronic device 10 is provided with a system
controller 11 including a CPU for controlling various operations of the
electronic device 10 and executing processing to check the connection of
the memory cartridge 20. An alarm device (not shown) is connected to the
system controller 11 for informing an operator of the fact that the
checked connection has been determined to be faulty when such a
determination is made. If the electronic device 10 is a digital electronic
still video camera, video data to be written in the memory 21 of the
memory cartridge 20 is applied from an image pick-up device (not shown) to
an A/D converting and signal processing circuit 12 in the form of an
analog signal. The circuit 12 subjects the video to an A/D conversion and
predetermined signal processing, thereby producing picture data applied to
a three-state buffer 13 by the data bus. A three-state buffer is one which
can establish a high output impedence in response to a control signal
inputted thereto, with the signal obtained from the output side of the
buffer at such time inhibiting an input to the buffer. A three-state
buffer ordinarily has a low output impedence, with a signal applied to the
input side thereof being introduced to the output signal intact. An
address bus and a control bus from the system controller 11 are connected
to the three-state buffer 13. The output side of the buffer is connected
to the connector 14 and also to the system controller 11.
The memory cartridge 20 is provided with a memory 21 including one or a
plurality of memory chips, a checking code generating circuit 22 for
generating a predetermined checking code, a multiplexer 23 for changing
over connection between the terminals 24 and the memory 21 or generating
circuit 22, and a power supply (not shown), such as a battery, for
supplying the generating circuit 22 with electric power. Normally, the
multiplexer 23 connects the terminals 24 to the memory 21 (side a). Upon
receiving a changeover control signal from a terminal 24A, the multiplexer
23 connects the output side of the checking code generating circuit 22 to
the terminals 24 (side b) for a fixed period of time.
As mentioned earlier, some of the terminals of connector 14 and the
corresponding connection terminals 24 of memory cartridge 20 are for
transmitting an address signal used to address the memory of the memory
cartridge 20. Some of the other of these terminals ar for transferring
data. Furthermore, there are terminals for transmitting a chip-select
signal CS, a read/write command R/W and control signals such as the
abovementioned changeover control signal (terminal 24A). Accordingly, when
the memory cartridge 20 is loaded in the electronic device 10, the address
bus, data bus and control lines inside the electronic device 10 are
connected to the corresponding buses and lines in the memory cartridge 20
via the connector 14 and terminals 24, and it becomes possible for the CPU
of the system controller 11 in electronic device 10 to directly access the
memory of the memory cartridge 20. Since a checking code is used in order
to check the state of the connections between all of the terminals 24 and
all of the terminals of connector 14, the checking code generated by the
generating circuit 22 is applied to all of the terminals 24 (except for
terminal 24A) via the multiplexer 23.
The general features of connection checking processing executed by the CPU
of electronic device 10 will now be described.
When the limit switch 16 issues a detection signal indicating that the
memory cartridge 20 has been loaded, the CPU of controller 11 outputs the
changeover control signal. This signal is applied to the multiplexer 23
and checking code generating circuit 22 via the terminal 24A and the
corresponding terminal of connector 14. Accordingly, the output side of
the checking code generating circuit 22 is connected to the terminals 24
and the circuit 22 generates a predetermined checking code. At the same
time, the system controller 11 applies a control signal to the three-state
buffer 13, whereby the output side thereof attains a high impedence. The
checking code generated by the generating circuit 22 is applied to the
system controller 11 through the multiplexer 23, terminals 24 and
connector 14. Since the buffer 13 presents a high output impedence (a high
input impedence with regard to the checking code), the checking code does
not enter the buffer 13.
The CPU of the system controller 11 investigates the inputted checking code
to determine whether it is a predetermined code. This can be achieved by
previously storing a checking code in the controller 11, and having the
controller 11 compare this code with the inputted checking code to
determine if they coincide. Alternatively, if the checking code generated
by the circuit 22 exhibits a certain regularity (e.g. 1's and 0's
repeating in alternating fashion starting with 1, such as 1010 . . .),
checking can be performed by investigating the code for this regularity.
Preferably, it is arranged so that the generating circuit 22 successively
generates two or more types of checking codes to transmit 1 and 0 signals
through all of the terminals 24 and all of the terminals in the connector
14. If no abnormality is found as a result of investigating all of the
checking codes, then the CPU stops outputting the changeover control
signal to switch the multiplexer 23 over to the side of memory 21, and the
circuit 22 stops generating the checking code. The program then proceeds
to predetermined processing regarding the memory cartridge 20, such as
processing for writing video data in a predetermined memory area. If even
one bit is found to be erroneous as a result of investigating the checking
code, a command is applied to the alarm device, which responds by issuing
an alarm to this effect. Obviously, depending upon the particular case, an
arrangement can be adopted in which an alarm is issued only if a decision
indicative of a normal connection is not rendered after the checking
processing is repeated a plurality of times.
It is permissible to adopt an arrangement in which, if the memory cartridge
possesses a CPU, the checking code is generated by this CPU. An
arrangement is also possible in which the memory cartridge is provided
with a cartridge loading detection switch, and a CPU within the cartridge
responds to loading detection by changing over the multiplexer 23 and
starting generation of the checking code.
Furthermore, in the above-described arrangement shown in FIG. 3, a
predetermined voltage can be applied to the terminal 14a, with the
changeover of multiplexer 23 and the generation of the checking code being
initiated by a voltage which will appear at the terminal 24a when the
memory cartridge is loaded. In this case, the voltage impressed upon the
terminal 24a would be sent to ground potential at the end of the checking
operation. Alternatively, the cartridge could be provided with a timer for
controlling the checking time period. When time runs out, the multiplexer
would be returned to the memory side and the generation of the checking
code would be terminated.
An embodiment of a digital electronic still video camera in accordance with
the present invention will now be described. Portions identical or similar
to those described above are designated by like reference characters.
FIG. 5 illustrates an embodiment of a digital electronic still video camera
in accordance with the present invention. The embodiment includes an
electronic still video camera 10 having an image pick-up section 30, and a
memory cartridge 20 connected to the camera 10 via a connector 17 in
loadable/unloadable fashion. Conceptually, the connector 17 includes the
above-described connector 14 and terminals 24. The connector 17 includes a
connector portion 18, described below.
The memory cartridge 20 includes, for example, an SRAM semiconductor memory
21 and is connected to the camera 10 by its connector 17 via a data bus as
well as address and control buses through which addresses, read/write
enable signals, chip-select signals, stobes and clocks are passed. The
connector 17 may have power feeder lines for the memory 21. If one frame
of a picture is expressed by data of 1M through 1.5M bits, the memory 21
can be a 24-frame memory device realized by two chips, where the SRAM has
a storage capacity of 16M bits per chip.
The image pick-up section 30 has a camera lens 31, a diaphragm 32, a
shutter 33, an image pick-up device 35, and other elements necessary for
taking still pictures, such as a photometer and range finder mechanisms, a
view finder (not shown) and drive mechanisms for driving these elements.
Focusing the lens 31, operating the diaphragm 32 and actuating the shutter
33, etc., are controlled by system controller 11. As will be described
later, the system controller 11 operates the image pick-up section 30,
such as the shutter 33, after verifying the electrical connection between
the memory cartridge 20 and the camera 10.
A solid-state image pick-up device such as a CCD or MOS is employed
advantageously as the image pick-up device 35. The solid-state image
pick-up device 35 has an image pick-up cell array 34 to which a color
filter is attached. In response to a clock signal received from a
synchronizing signal generating circuit 43, the image pick-up device
successively outputs a color-modulated video signal in the form of a dot
(pixel) sequence. In the image pick-up device 35, any suitable array of
photosensitive cells constituting the image pick-up cell array 34, namely
any suitable number of pixels of the photosensitive region, can be used.
Also, the array of color segments of the color filter can be of any type.
The video signal output of the image pick-up device 35 is applied to the
analog-digital converting and signal processing circuit 12. As mentioned
above, the circuit 12 converts the analog input video signal into the
corresponding digital data of e.g. eight bits and outputs the resulting
digital signal to the connector 17 via a changeover switch circuit 48
(terminal a). The digital data is finally applied to the dat | | |
