Electronic watch

Provided is an electronic watch capable of surely acquiring a movement start position and a stop position of a hand when the hand moves at high speed such as a case of manual correction by a winding stem or the like, while reducing a load on a CPU. The electronic watch includes: a decode circuit for outputting data corresponding to regions acquired by segmenting a movement range of the hand; and a position information circuit for automatically acquiring region data corresponding to the movement start position of the hand and region data corresponding to the stop position thereof and sending a notification to the CPU when acquiring both the data. In this manner, the CPU can stop until the acquisition of both the data, thereby reducing the load on the CPU.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/JP2012/062718 filed May 17, 2012, claiming priority based on Japanese Patent Application No. 2011-111277 filed on May 18, 2011. The contents of each of the above documents are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to an electronic watch having a time display function by hands and a calendar function and being capable of time difference correction by a crown operation.

BACKGROUND ART

Studies have hitherto been made on an electronic watch equipped with a position detection function for detecting the position of a display member such as a hand to control various kinds of correction operations. Patent Literature 1 discloses an electronic watch in which a contact spring mounted to a 24-hour wheel and a detection pattern are used to set a detection section in the range of from 0 degrees to 360 degrees in a hand rotation direction and, when the position of 24 o'clock (midnight) is detected, a day dial is controlled to be advanced one day. The technology of Patent Literature 1 produces its effect on the assumption that the hand is mounted at the 12 o'clock position with high accuracy, but this hand mounting work requires advanced skills and a long work time.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

Patent Literature 1 describes that the electronic watch also supports the mechanical correction of the hour hand alone by a winding stem, that is, so-called “time difference correction”. However, unlike when the position slowly changes such as normal hand movement, the time difference correction involves rotating the hour hand (=24-hour wheel) at high speed, and hence data of the detection pattern changes at high speed as well. However, a microcomputer for use in such a multi-function watch is very low in operation speed in order to reduce power consumption, and is therefore incapable of responding to the high-speed data change of the detection pattern, with the result that an erroneous determination may occur.

Even if a high-speed microcomputer can be used, the microcomputer becomes busy in performing detection pattern processing during the time difference correction, with the result that other processing may not be executed.

In view of the above, it is an object of the present invention to provide an electronic watch in which the hand mounting work can be efficiently performed and which is capable of date indicator driving through an accurate 24-hour determination even when the hand rotates and moves at high speed.

Solution to Problem

In order to solve the above-mentioned problem, an electronic watch according to the present invention includes: a decode circuit configured to segment a whole movable region of an indicator such as a hand and for outputting region data corresponding to the segmented regions; a position information circuit configured to acquire region data corresponding to a movement start position of the indicator (hereinafter referred to as “movement start region data”) and region data corresponding to a stop position after start of movement (hereinafter referred to as “stop region data”), and configured to output, when the movement start region data or the stop region data is acquired, an acquisition signal indicating that one or both of the data are acquired; and a control unit configured to acquire the movement start region data and the stop region data from the position information circuit in response to the acquisition signal from the position information circuit, and configured to perform processing relating to the movement of the indicator.

Advantageous Effects of Invention

According to the present invention, even when the control unit such as a CPU is stopped, the position information circuit automatically acquires the movement start position and the stop position of the indicator such as a hand, and outputs the acquisition signal to the CPU after the acquisition. Upon receiving the acquisition signal, the CPU boots up to acquire the movement start position and the stop position and can execute the processing such as date indicator driving. Consequently, the load on the CPU can be reduced to achieve low power consumption.

Further, the CPU can be allocated to another work while the position information circuit is automatically acquiring the movement start position and the stop position, and hence the CPU can be efficiently operated.

DESCRIPTION OF EMBODIMENTS

Referring to the drawings, a description is now given of an electronic watch according to the present invention and the basic principle and embodiments thereof.

An electronic watch10according to the present invention is, for example, as illustrated inFIG. 24, a wristwatch having analog hands and date indication. As the hands, an hour hand11, a minute hand12, and a second hand13are coaxially provided. The date indication printed on a day dial16is seen from a date window15provided in a watch face14. The electronic watch10as used herein is equipped with at least the analog hour hand11and an analog date indication mechanism (the day dial16in this case) as indicators. Note that, the day dial16illustrated inFIG. 24is a typical analog date indication mechanism, but another mechanism such as a hand mechanism may be used instead. Time correction is performed by operating a crown17. Then, date correction is performed along with at least the time correction. Specifically, when the time is corrected in a manner that the time indication of the hands move beyond 12 o'clock (midnight), the date is corrected in conjunction with the time correction. The electronic watch10illustrated inFIG. 24shows the time in the typical 12-hour format, and hence in this case, the date is put forward or back one day each time the hour hand11passes the 12 o'clock (midnight) position twice.

A widely known mechanism in the analog watch of the type in which the hands and the date indication mechanism are moved in conjunction with each other as described above is to mechanically connect the hour hand11and the day dial16to each other. In this mechanism, however, the date indicator driving is performed slowly by spending about 1 hour around 12 o'clock (midnight), and hence it is hard to read the date before and after the change in date. In view of this, such a mechanism that updates the date at high speed when the time indication of the hands moves beyond 12 o'clock (midnight) (called “just update”, “datejust”, “fast date indicator driving”, etc.) has been put into practical use. Also the electronic watch10has this mechanism. As an example, the electronic watch10as used herein has the mechanism in which a drive mechanism for the hands (namely, the hour hand11, the minute hand12, and the secondhand13) and a drive mechanism for the date indication mechanism (namely, the day dial16) are separated from each other so that the date indication mechanism is driven by electronically detecting that the time indication of the hands moves beyond 24 o'clock.

FIG. 25is a diagram illustrating the operation of updating the date in the electronic watch10according to the present invention. For instance, as an example, in the state illustrated in the left ofFIG. 25, the electronic watch10indicates 6 at 11:09:35 p.m. In this case, when the crown17is operated to rotate the hour hand11in the forward direction (namely, the clockwise direction) so that the time is adjusted to 00:09:35 a.m. beyond 12 o'clock (midnight) as illustrated in the right ofFIG. 25, the day dial16is advanced instantaneously (within about 1 to 2 seconds) as illustrated inFIG. 25, and the displayed date is updated from 6 to 7. The same holds true when the reverse operation is performed.

Note that, the operation of rotating the hour hand11by operating the crown17may be a general time adjustment operation, that is, an operation of rotating the hour hand11and the minute hand12in conjunction with each other, or may be a time difference correction operation, that is, an operation of rotating only the hour hand11independently of the other hands.

FIG. 26is a schematic perspective view illustrating the drive mechanism for the hands of the electronic watch10according to the present invention. Rotational power taken out from a rotor21inserted in an opening portion of a motor stator20illustrated inFIG. 26is transmitted to an hour wheel27while being reduced via respective gears of a fifth wheel22, a fourth wheel23, a third wheel24, a center wheel25, and a minute wheel26. The hour hand11is fixed to the hour wheel27, the minute hand12is fixed to the center wheel25, and the second hand13is fixed to the fourth wheel23.

A winding stem28to which the crown17is mounted is engaged with the hour wheel27via intermediate wheels29,30, and31, and hence, when the crown17is rotated, the hour wheel27, namely the hour hand11, can be rotated. In this case, the gears of the hour wheel27have a structure in which an upper gear27aand a lower gear27bare overlapped with each other. The upper gear27ameshes with the intermediate wheel31, and the lower gear27bmeshes with a pinion of the minute wheel26. Then, the upper gear27ais mounted integrally with a cannon part27cof the hour wheel27, and the lower gear27bis mounted integrally and rotatably with the cannon part27cby a spring mechanism27d. With this mechanism, when the winding stem28is rotated, the upper gear27arotates so that the hour hand11rotates in conjunction therewith, but the minute wheel26does not rotate because the cannon part27cand the lower gear27bare separated from each other due to an elastic deformation of the spring mechanism27d. Thus, the rotation of the winding stem28and the rotations of the minute hand12and the second hand13are not performed in conjunction with each other. This mechanism realizes a time adjustment operation in which only the hour hand11is rotated independently of the minute hand12and the second hand13.

In addition, a switch wheel32meshes with the intermediate wheel31, and the switch wheel32rotates in conjunction with the rotation of the hour hand11. Then, a switch spring33is mounted to the switch wheel32, and the contact spring33also rotates in synchronization with the rotation of the switch wheel32. The switch spring33is brought into contact with a circuit board (not shown), and rotates while keeping in contact with the circuit board. In addition, a specific wiring pattern is provided on the circuit board in advance, and by detecting whether or not the wiring pattern and the switch spring33are electrically connected to each other, a rotation position of the switch spring33and further a rotation position of the hour hand11can be detected.

Note that, the mechanism of the electronic watch10as described herein is merely an example, and it should be understood that any other kind of electronic watches can be used as long as the electronic watch has at least the analog hour hand11and the analog date indication mechanism, and the time indicated by the hour hand11and the date displayed on the date indication mechanism are in conjunction with each other at the time of time correction.

First, a description is given of the basic principle of the present invention.

(1) Basic Concept

FIG. 1Asimply illustrates a time display surface100-4of the watch, illustrating an hour hand determination region to be set in the present invention. Specific regions A100-1and B100-2are placed around a 12 o'clock (midnight) position100-5at which the date is updated, and a region other than the regions A and B is defined as a region C100-3.

When the presence of the hour hand in the region A, B, or C is recognized by the above-mentioned mechanism or another mechanism such as an encoder, and when the movement of the hour hand from the region A to the region B is recognized, it is determined that the hour hand has passed 12 o'clock (midnight), and the date is put forward one day, and when the movement of the hour hand from the region B to the region A is recognized, it is determined that the hour hand has passed 12 o'clock (midnight), and the date is put back one day. This is the basic concept.

Note that, the watch illustrated inFIG. 1Ashows the time in the 12-hour format, and an hour hand203to be described later passes the 12 o'clock (midnight) position100-5twice a day. A decode circuit1to be described later supports a 24-hour wheel (not shown) that makes one turn in 24 hours, and is configured to generate a decoded signal to be described later only around 12 o'clock (midnight). The details are irrelevant to the invention of the present application, and hence the description thereof is omitted.

FIG. 1Bis a correspondence diagram illustrating a relationship between a position of the hour hand203and an output of the decode circuit1to be described later corresponding to the position.

InFIG. 1B, reference symbols PK1to PK3represent the signal names of the output of the decode circuit1;202-2, a boundary of a hand position detection region;202-3, a region “0”;202-4, an output pattern of the decode circuit with respect to the hand position detection region;202-5, a movement start position of the hour hand203;202-6, a stop position of the hour hand203;202-7, an hour face of the watch;202-8, an hour mark;202-9, a region “1” as a small divided region; and202-10, a movement direction of the hour hand.

Note that, the indication members of the watch of the present invention are, in addition to the hour hand203, a minute hand, a second hand, a day dial that indicates the date, and the like, but those do not constitute the present invention and the illustration thereof is therefore omitted.

Examples of the date indication method include the use of the day dial or a day-of-week dial as well as a display by a small hand and a digital display by an LCD or the like. The selection of the display method is not directly relevant to the present invention, and the selection is optional.

As illustrated inFIG. 1B, the region A100-1and the region B100-2are more finely divided into small regions, and different values “1” to “6” are set to be output when the hour hand203is located in the respective small regions.

The following is the reason why the region A100-1and the region B100-2are divided into such small regions.

Originally, the 12 o'clock (midnight) position of the hour hand203needs to be located in the region between “3” and “4”. However, even if the region between “2” and “3” corresponds to the 12 o'clock (midnight) position in terms of hand mounting accuracy, it is only necessary to store data so that the region between “2” and “3” may correspond to the 12 o'clock (midnight) position by internal processing of the watch. Performing such processing eliminates the need of high hand mounting accuracy, thus simplifying a hand mounting step and thereby cutting down the cost.

This correspondence is performed by, for example, installing a dedicated mode for storing the above-mentioned data corresponding to the 12 o'clock (midnight) position in a memory region (not shown) inside the watch at the time of the hand mounting of the hour hand203. This correspondence originally needs to be performed only at the time of the hand mounting, but, if the hand has displaced by impact or the like, the correspondence may be performed as the occasion demands.

Note that, for simple description, the following description assumes that the positions of “3” and “4” correspond to the 12 o'clock (midnight) position of the hour hand203as illustrated inFIG. 1B.

The region C is not finely classified, but the value “0” is set in the region C. The reason is because the region C is a region that is not directly used for determining the 12 o'clock (midnight) position of the hand.

In this manner, the number of pieces of data to be decoded is reduced to simplify the structure of the decoder to be described later.

The small regions illustrated inFIG. 1Bare divided as six small regions in total, three regions A and three regions B. The reason is because those regions can be produced easily only with the bifurcated contact spring and the three input terminals disclosed in Patent Literature 1, for example.FIG. 1Billustrates a pattern diagram of the input terminals PK in the case where the regions are produced with such a structure. Note that, the values of PK do not match with the values “1” to “6” of the small regions, but can be converted through an appropriate decoder. Thus, the following description assumes that the small regions “1” to “6” are acquired as the numerical values output through the decoder.

Note that, the mechanical and electrical configurations of the decoder are not essential for the present invention, and hence the description thereof is omitted.

It should be understood that the present invention is not limited to the decoded pattern illustrated inFIG. 1B. The number of the small regions, and the decoded numerical values corresponding to the respective small regions and the region C can be arbitrarily set as long as the present invention can be embodied.

(3) Method of Determining the Passage Through the 12 O'Clock (Midnight) Position

Using a method to be described later, decode data corresponding to a start position and a stop position of hand driving is stored, and the pieces of decode data are compared after the stop of the hand driving, to thereby determine the presence/absence of the passage through the 12 o'clock (midnight) position and its direction.

Specifically, when “1” to “3” being the region A are stored as the start position and “4” to “6” being the region B are stored as the stop position, the movement from the region A to the region B is recognized and the date is put forward one day, and when “4” to “6” being the region B are stored as the start position and “1” to “3” being the region A are stored as the stop position, the movement from the region B to the region A is recognized and the date is put back one day. In the following, the computation processing and the mechanical operation for advancing and returning the date indication are collectively referred to as “date indicator driving processing”.

EMBODIMENTS

Next, a specific circuit configuration for achieving the above-mentioned basic principle is described with reference to the drawings.

FIG. 2is a block diagram illustrating an overall system configuration of an electronic watch according to embodiments of the present invention. Note that,FIG. 2is used in common to the individual embodiments to be described later.

Reference numeral1represents the above-mentioned decode circuit, which outputs a value corresponding to the position of the hour hand203(not shown inFIG. 2). Reference numeral2represents a hand position information circuit for receiving the output from the decode circuit1, which is the feature of the present invention, to determine and store information relating to the position of the hour hand203, specifically, a movement start position and a stop position.

Reference numeral3represents a CPU;4, a crystal oscillator circuit using a crystal oscillator5;6, a ROM for storing a program; and7, a RAM to be used for various kinds of information processing. Those components construct a general microcomputer. The hand position information circuit2is constructed as a peripheral circuit of the CPU3, and various kinds of hand position information are transmitted to the CPU3via a bus or a control line. In other words, the features of the overall system of the present invention reside in the decode circuit1and the hand position information circuit2, and a commonly-used watch microcomputer system can be used for the other portions.

The hand position information circuit2is booted up by the CPU3in a time difference correction mode in which the hour hand203moves at high speed and other such modes. In other states such as a normal use state in which the hour hand203moves at low speed or stops, the hand position information circuit2is stopped. During the stop of the hand position information circuit2, the output of the decode circuit1is configured so as to be directly processed by the CPU3not via or just passing through the hand position information circuit2.

With this configuration, the output of the decode circuit1is configured so as to be directly processed by the CPU3and the hand position information circuit2is stopped in the state in which the hour hand203moves at low speed or stops, and the hand position information circuit2can be operated only in the time difference correction mode in which the hour hand203moves at high speed and other such modes. Consequently, the power consumption can be reduced.

Note that, inFIG. 2, the hand position information circuit2is illustrated as being configured inside the microcomputer, but the present invention is not limited thereto, and the hand position information circuit2may be configured as another circuit (IC) outside the microcomputer.

In this manner, a commonly-used commercially available watch microcomputer can be used as the microcomputer.

The decode circuit1is connected to input terminals PK1to PK3of the hand position information circuit2. To the input terminals PK1to PK3, the values illustrated inFIG. 1Bare output with respect to the regions “0” and “1” to “6”.

Note that, the numbers of the regions “1” to “6” do not match with the decoded data as described above, but, by converting the regions through an appropriate decoder (not shown), the hand position information circuit2performs processing with the values “0” and “1” to “6”. The values “0” and “1” to “6” after processed by the hand position information circuit2are hereinafter referred to as “region data”.

As described above, the decode circuit1according to this embodiment can be produced by a simple configuration of the bifurcated contact spring and the three input terminals PK1to PK3, and hence such a decode circuit is employed. It should be, however, understood that the decode circuit is not limited thereto.

Based on hour hand detection region data that is input from the decode circuit1in accordance with the movement of the hour hand203, the hand position information circuit2holds a movement start region and a movement stop region of the hour hand by a method to be described later, and outputs the movement start region and the movement stop region to the CPU3. Based on the movement start region data and the movement stop region data acquired from the hand position information circuit2, the CPU3determines whether or not the hour hand has moved beyond the 12 o'clock (midnight) position, and performs the date indicator driving processing.

Next, the basic operation of the hand position information circuit2is described with reference to a block diagram ofFIG. 3and a flow chart ofFIG. 4.

As illustrated inFIG. 3, the hand position information circuit2is roughly divided into a start circuit150and a stop circuit151, and the operations thereof are controlled by the control circuit105.

The start circuit150is a circuit for acquiring decoded data of a region where the hour hand starts to move (hereinafter referred to as “movement start region data”). When the automatic position acquisition by the hand position information circuit2is necessary for the time difference correction or the like, the control circuit105receives a boot-up command from the CPU3to boot up the start circuit150, and the start circuit150executes the operation of acquiring the start region data. When the acquisition of the movement start region data is finished, the control circuit105stops the operation of the start circuit150except for a part of the circuit for fetching the data of the decode circuit1.

The stop circuit151is a circuit for acquiring decoded data of a region where the hour hand stops (hereinafter referred to as “movement stop region data”). The stop circuit151continues its stopping status even after the boot-up of the start circuit150, and, when the start circuit150acquires the start region data and stops, the stop circuit151is booted up by the control circuit105to execute the operation of acquiring the stop region data. When the acquisition of the stop region data is finished, the control circuit105stops the stop circuit151.

As described above, the start circuit150operates first, and the stop circuit151operates after the end of the operation of the start circuit150. In other words, the start circuit150and the stop circuit151operate independently and do not operate simultaneously. This is because the start circuit150and the stop circuit151do not need to be operated simultaneously in view of the roles of the respective circuits. In this manner, low power consumption of the hand position information circuit2is achieved.

The timing at which the stop circuit151starts its operation may be the same as the timing at which the start circuit150finishes its operation. In this case, the stop circuit151starts to operate without waiting for the end of the operation of the start circuit150, and hence, when the movement of the hour hand has stopped immediately after the start of movement, the time until the stop determination can be decreased. For easy understanding of the operation, the following description assumes that the stop circuit151operates after the end of the operation of the start circuit.

When the start circuit150in the hand position information circuit2is permitted to operate (ST4-1), the start circuit150regularly acquires region data output from the decoder circuit1(ST4-2). Then, the pieces of the successively-acquired hour hand detection region data are compared (ST4-3). When the pieces of region data do not match with each other (ST4-3: NO), the start circuit150recognizes that the hour hand203has started to move, and stores the hour hand detection region data at the time of the start of movement as the movement start position (ST4-4). On the other hand, when the compared pieces of region data are not different from each other (ST4-3: YES), the start circuit150determines that the hour hand has not moved, and continues the comparison.

Upon the detection of the start of movement of the hour hand, the control circuit stops the start circuit150(ST4-5), subsequently permits the operation of the stop circuit151(ST4-6), and regularly acquires the region data from the decoder circuit1(ST4-7). The stop circuit151compares the newly read region data with the region data read in the previous sampling (ST4-8). When the pieces of the region data match with each other (ST4-8: YES), the stop circuit151recognizes that the hour hand203has stopped, and then determines whether or not the pieces of the region data match with each other for a predetermined period of time (ST4-9). When the pieces of the region data match with each other for the predetermined period of time (ST4-9: YES), the stop circuit stores the region data as the movement stop position (ST4-10), and stops its operation (ST4-11).

On the other hand, when the comparison result in ST4-8indicates that the pieces of data do not match with each other (ST4-8: NO) or when it is not confirmed in ST4-9that the pieces of data match with each other for the predetermined period of time (ST4-9: NO), the stop circuit151further continues the comparison of the region data. Note that, the predetermined period of time is set so that it is surely determined that the hour hand has stopped during the passage through the region C, thereby being compatible also with the continuous rotation of the hand (continuous hour hand position correction by the crown). The details are described later.

First Embodiment

FIG. 5is a block diagram illustrating a detailed configuration of the hand position information circuit2according to a first embodiment of the present invention. In the hand position information circuit2according to the first embodiment, the start circuit150includes a first start register101for determining the start of movement, a start position holding register111for storing a start position, a movement detection circuit104for detecting the start of movement by comparing the first start register101and a first stop register102to be described below and for outputting a signal S4that indicates the detection, and a start HR circuit109for outputting a signal S9that informs the CPU3of the detection of the start of movement, and the stop circuit151includes the first stop register102and a second stop register103to be used for determining the start of movement and determining the stop, a stop position holding register112for storing a stop position, a stop flag circuit119for outputting a signal S19that boots up a stop determination circuit107to be described below, the stop determination circuit107that is booted up by the signal S19to determine the stop by counting a stop time, and a stop HR circuit110for outputting a signal S10that informs the CPU3of the detection of the stopping of movement. The role of the control circuit105is to control the overall hand position information circuit2as shown inFIG. 3.

A circuit system surrounded by a chain line is the start circuit150and a circuit system surrounded by another chain line is the stop circuit151. As used herein, HR stands for a halt release signal (signal for releasing the halt state of the CPU3), and is a processing request signal for the CPU3.

The decode circuit1inputs region data to the hand position information circuit2in accordance with a region at which the hour hand203is located. In the hand position information circuit2, region data SD is input to the first start register101and the first stop register102. The first start register101needs to fetch the data all the time, and hence operates also during the stop of the start circuit150. An output S1of the first start register101, which is the latest region data, is input to the start position holding register111and the movement detection circuit104. An output S2of the first stop register102, which is the latest region data, is input to the second stop register103, the stop position holding register112, and the stop flag circuit119. An output S3of the second stop register103is input to the movement detection circuit104and the stop flag circuit119.

The output S4of the movement detection circuit104is input to the start HR circuit109and the control circuit105, and the output S19of the stop flag circuit119is input to the stop determination circuit107. An output S7of the stop determination circuit107is input to the control circuit105and the stop HR circuit110, and the outputs S9and S10of the start HR circuit109and the stop HR circuit110are input to the CPU3, respectively.

As a clock signal for the registers, a port clock signal SP is input to the first start register101and the control circuit105. As described above, the port clock signal SP is always output during the operation of the hand position information circuit2.

An output S5of the control circuit105is a clock signal that is produced based on the port clock signal SP and output only when necessary, and is input to the start position holding register111.

An output S6of the control circuit105is also a clock signal that is produced based on the port clock signal SP and output only when necessary, and is input to the stop position holding register112.

Similarly, an output S8of the control circuit105is a clock signal that is produced based on the port clock signal SP and output only when necessary, and is input to the first stop register102, the second stop register103, and the stop determination circuit107.

Description of the Operation in the First Embodiment

Next, the operation of the hand position information circuit2shown inFIG. 5is described with reference to a flow chart ofFIG. 6.

[1] Acquisition of Movement Start Region

The first start register101acquires the region data SD from the decode circuit1at a change timing of the port clock signal SP supplied from the CPU3(ST6-1). The change timing as used herein refers to any one of a rising edge and a falling edge of the signal.

The output S3of the second stop register103holds the region data SD indicating the region at which the hour hand203stopped last time. The movement detection circuit104compares the output S3of the second stop register103and the output S1of the first start register101to each other (ST6-2). When the pieces of region data are different from each other (ST6-2: NO), it is determined that the hour hand203has started to move, and S4is generated (ST6-3).

Note that, the “generation of signal S*” as used herein means an activation of a clock signal that has been stopped in the case of a clock signal, and means outputting an active signal, signal “1” in this embodiment, in the case of a control signal.

Upon the generation of S4meaning the detection of the start of movement, the control circuit105generates S5as a start position holding signal, and controls the start position holding register111to hold a value of the first start register101(ST6-16). In this case, the start position holding register111only needs to hold the region data acquired when the hour hand has started to move, and hence may hold the output S3of the second stop register103. In addition, upon the generation of the start position holding signal S5, the start HR circuit109generates S9as an HR signal indicating the detection of movement start position data to the CPU3to prompt the CPU3to acquire the region data (ST6-17). The CPU3receives the HR signal S9and fetches region data S11held by the start position holding register111(ST6-18). In this manner, the fetch of the movement start position data is finished, and the operation of the start circuit130is finished.

[2] Acquisition of Movement Stop Region

Upon the generation of S4meaning the detection of the start of movement, the control circuit105generates S8as the operating clock for the first stop register102and the second stop register103(ST6-4).

At a change timing of S8, the control circuit105controls the first stop register102to hold the region data SD of the output of the decode circuit1(ST6-5), and simultaneously controls the second stop register103to hold the output S2of the first stop register102(ST6-6).

The stop flag circuit119compares S2and S3, which are the outputs of the first stop register102and the second stop register103(ST6-7). When both the data are equal to each other (ST6-7: YES), the stop flag circuit119determines that the hour hand203is possibly in the stop state, and generates the stop flag S19(ST6-9). When S2and S3are not equal to each other (ST6-7: NO), the stop flag circuit119determines that the hour hand203is not in the stop state but is moving, and the processing is performed again starting from the fetch of the region data SD of the decode circuit1(ST6-5) without generating S19(ST6-8).

The stop determination circuit107counts the time during which the stop flag S19is generated (S19=1) (ST6-10). When S19is continuously generated for a predetermined period of time (ST6-10: YES), the stop determination circuit107determines that the hour hand has stopped, and generates S7(ST6-11).

On the other hand, when S19is not generated for a predetermined period of time (ST6-10: NO), the stop determination circuit107considers the hour hand not to have stopped completely, and resets S19to 0 (ST6-8). Then, the processing is performed again starting from the fetch of the region data SD of the decode circuit1(ST6-5).

Note that, the stop determination circuit107is configured as a timing counter (timer) for counting an appropriate clock. The clock for counting is configured to be supplied to the stop determination circuit107only when S19=1. The details of the stop determination circuit107are described in a fourth embodiment of the present invention.

Upon the generation of S7indicating the stop determination, the control circuit105generates a signal S6for operating the stop position holding register112(ST6-12), and the stop position holding register112holds the output S2of the first stop register102(ST6-13). Further, upon the generation of S7, the stop HR circuit110generates S10to prompts the CPU3to acquire the stop position region data (ST6-14), and the CPU3fetches the region data S12of the stop position holding register112(ST6-15). Note that, upon the generation of S10, S8being the operating clock for the first stop register102and the second stop register103is stopped, and thereby, the operation of the stop circuit151is finished.

[3] Processing of the CPU3

Next, the operation of the CPU3for acquiring information of the hand position information circuit2is described with reference to a flow chart illustrated inFIG. 7.

The CPU3normally stops in the HALT state, and starts its operation in response to a HALT release signal (HR signal). The CPU3waits in the HALT state for an HR signal S9indicating the acquisition of the start position (ST7-1), and starts its operation when the HR signal S9is generated (ST7-1: YES) to acquire region data S11indicating the movement start position (ST7-2). When the region data S11is acquired, the CPU3changes to the HALT state again. Note that, the HR signal S9is reset by the CPU3when the HALT is released. The same holds true for the other HR signals.

Subsequently, the CPU3waits in the HALT state for an HR signal S10indicating the acquisition of the stop position (ST7-3), and starts its operation when the HR signal S10is generated (ST7-3: YES) to acquire region data S12indicating the movement stop position (ST7-4). Based on the acquired movement start position region data and movement stop position region data, it is determined whether the hour hand203has passed the 12 o'clock (midnight) position (ST7-5). When the hour hand203has passed the 12 o'clock (midnight) position (ST7-5: YES), the operation of updating the date indication is performed (ST7-6).

As described above, even when the hour hand203operates at high speed, the hand position information circuit2can acquire the movement start position and the movement stop position of the hour hand203, and the operation of the CPU3can be stopped during this period. By setting the speed of the operating clock (such as SP) of the hand position information circuit2to be lower than the speed of the operating clock of the CPU3, the power consumption can be reduced as compared with the case where the processing is performed by the CPU3.

Further, in the case where the CPU3is not brought into the HALT state, the CPU3can be allocated to another processing, and hence the processing efficiency of the CPU3can be improved.

[4] Description with Reference to a Time Chart of the Hand Position Information Circuit2

FIG. 8illustrates the operation of the hand position information circuit2illustrated inFIG. 5in the form of a time chart, illustrating the flow of data of the signal lines illustrated inFIG. 5in time series. Note that, the time range marked with a line indicates an active “1”, and the time range not marked with a line indicates a negative “0”. A description is given herein of the example where the hour hand203has moved from the region “1” to the region “4”.

The first start register101in the start circuit150acquires the hour hand position region data SD from the decoder1in response to the port clock SP, and the movement detection circuit104compares the stop region data S3of the second stop register102and the output S1of the first start register101. When both the data do not match with each other, the movement detection signal S4becomes “1”, and the start register control signal S5is generated to hold the region data of the first start register101in the start position holding register111. After that, the start HR signal S9becomes “1”, and the CPU3acquires the region data of the start position holding register111.

Note that, the port clock SP is a clock to be supplied continuously from the CPU3during the operation of the hand position information circuit2. The operation thereof does not need to be described particularly, and hence the illustration is omitted in the following time charts.

In response to the generation of S4indicating the movement start detection of the hour hand203, the stop register operating signal S8as the clock for the first and second stop registers102and103is generated.

In response to the clock S8, the first and second stop registers102and103acquire the region data SD from the decoder circuit1in a serial manner. When the outputs of the first and second stop registers102and103are the same data, the output S19of the stop flag circuit119becomes “1” (TM1). When the period of “1” lasts for a predetermined period of time, the output S7of the stop determination circuit107becomes “1” to generate the stop register control signal S6(TM2), and the region data of the first stop register102is held in the stop position holding register112. After that, the stop HR signal S10becomes “1”, and the CPU3acquires the region data of the stop position holding register112. After that, the CPU determines whether to perform the date indicator driving based on the region data of the start position holding register and the stop position holding register, and performs the processing.

As understood fromFIG. 8, except for the port clock SP for the first start register, the clocks S5and S8for data acquisition into the registers are configured to be generated only when the holding operation of the corresponding register is necessary. In this manner, an unnecessary clock operation is suppressed to reduce the power consumption.

Besides, the CPU3stops its operation except for the acquisition of the start position data S11and the stop position data S12, and hence the power consumption can be reduced.

Second Embodiment

The processing of the hand position information circuit according to the first embodiment is effective when the hour hand has moved in the range of from “1” to “6” of the detection regions. On the other hand, if the region “0” is finely divided as exemplified by the regions “1” to “6” and a decoded signal corresponding to each region is output, the hand position of the hour hand can be grasped all the time, and the start and stop of the movement can quickly be detected. However, the object of this system is to determine whether or not the hour hand has moved beyond the 12 o'clock (midnight) position, and hence there is a little advantage in acquiring position information of the hour hand in a region other than the plurality of regions around the 12 o'clock (midnight) position. Further, if the number of combinations of decoded data is increased, decoding cannot be achieved by a simple configuration of the bifurcated contact spring and the three input terminals PK1to PK3as described above, which is disadvantageous in terms of cost and size. Thus, in this embodiment, the region other than the regions “1” to “6” around the 12 o'clock (midnight) position is defined as the region “0” and is represented by single decoded data.

The second embodiment enables the determination of the rotation direction of the hour hand even when the hour hand has moved to pass the region “0” or to stop in the region “0” or when the region “0” is the start position.

Specifically, the feature of the second embodiment resides in that, only when the hour hand has passed the region “0” or when the hour hand has started to move from the region “0”, data on a region at which the hour hand has arrived next to the region “0” is held in the start position holding register111, and that, when the hour hand has stopped in the region “0”, data on a region at which the hour hand has arrived just before the region “0” is held in the stop position holding register113. This processing is hereinafter referred to as “region ‘0’ processing”.

Prior to describing the configuration of the second embodiment, the problem that occurs when the hour hand has passed the region “0” or stopped in the region “0” or when the region “0” is the start position is described with reference toFIGS. 9A to 9D.

FIGS. 9A, 9B, 9C, and 9Ddistinguish movement patterns of the hour hand, illustrating how the region data acquired by the start position holding register111and the stop position holding register112differs depending on the presence/absence of the region “0” processing.

The column D1inFIGS. 9A to 9Dindicates the pattern of how the hour hand moves among the respective zones A, B, and C. The column D2gives a specific example of the hour hand movement pattern of the column D1, in which the pattern is classified into the routes “i” and “ii” depending on the movement direction.

FIGS. 9A and 9Cillustrate the case where the processing on the region “0” is not performed. The column D3illustrates pieces of hour hand detection region data that are output from the decode circuit in the short hand movement routes “i” and “ii” illustrated in the column D2. The columns D5and D6illustrate pieces of region data of the start position holding register111and the stop position holding register112to be output to the CPU3, respectively. The column D4indicates the necessity of date indicator driving. Note that, the necessity as used herein indicates whether or not the date indicator driving is originally necessary in each of the cases of the routes “i” and “ii”, and does not indicate the result determined based on the region data of the start position holding register111and the stop position holding register112.

FIGS. 9B and 9Dillustrate the case where the above-mentioned processing on the region “0” is performed.FIGS. 9B and 9AandFIGS. 9D and 9Cdescribe the same hour hand movement patterns.

[1] Description of Movement Pattern C1

In the hour hand movement pattern of the column D1inFIGS. 9A and 9B, the hour hand moves from one of the zone A and the zone B to the other. In the example of the hour hand movement of the column D2inFIGS. 9A and 9B, the hour hand203moves from the detection region “1” to the detection region “4”. In the route “i”, the hour hand detection region changes in the order of “1”, “2”, “3”, and “4”. In the route “ii”, the hour hand detection region changes in the order of “1”, “0”, “6”, “5”, and “4”. In the route “i”, the hour hand moves beyond the 12 o'clock (midnight) position, and hence the date indicator driving is necessary. In the route “ii”, the date indicator driving is unnecessary.

InFIG. 9A, the region “0” processing is not performed, and hence, when the hour hand passes the region “0”, as indicated by the register values of the columns D5and D6, the start position holding register value and the stop position holding register value are identical in the route “i” and the route “ii”, and hence the rotation direction cannot be discriminated.

InFIG. 9B, in the route “i”, the start position holding register value holds “1”, and the stop position holding register value holds “4”. On the other hand, in the route “ii”, the hour hand passes the region “0”, and hence, by performing the region “0” processing, the start position holding register value holds “6” that is the region next to the region “0”, and the value of the stop position holding register112holds “4”. Thus, the CPU3can determine the rotation direction of the hour hand and the necessity of the date indicator driving extremely easily based on whether or not the regions “3” and “4” whose boundary is the 12 o'clock (midnight) position are included between the start position holding register value and the stop position holding register value. Specifically, in the case of the route “i”, the hour hand moves from “1” to “4” and beyond the hour hand detection regions “3” and “4” corresponding to the 12 o'clock (midnight) position and hence the date indicator driving is performed, and, in the route “ii”, the hour hand moves from “6” to “4”, and this movement does not correspond to the date indicator driving condition and hence the date indicator driving is not performed.

[2] Description of Movement Pattern C4

The hour hand movement pattern of the column D1inFIGS. 9C and 9Dillustrates the case where the hour hand moves from the zone A or the zone B to the zone C and stops in the region “0”.

In the example of the hour hand movement of the column D2, the hour hand moves from the hour hand detection regions “2” to “0”. In the route “i”, the hour hand detection region changes in the order of “2”, “3”, “4”, “5”, “6”, and “0”. In the route “ii”, the hour hand detection region changes in the order of “2”, “1”, and “0”. In the route “i”, the hour hand moves beyond the 12 o'clock (midnight) position and hence the date indicator driving is necessary. In the route “ii”, the date indicator driving is unnecessary.

InFIG. 9C, the region “0” processing is not performed, and hence, similarly to the example illustrated inFIG. 9A, as indicated by the register values of the columns D5and D6, the start position holding register value and the stop position holding register value are identical in the route “i” and the route “ii”, and hence the rotation direction cannot be discriminated.

InFIG. 9D, by performing the above-mentioned processing on the region “0”, in the route “i”, the start position holding register value holds “2”, and the stop position holding register value holds the region “6” that is a region just before the region “0” at which the hour hand has stopped. On the other hand, in the route “ii”, the start position holding register value holds “2”, and the value of the stop position holding register becomes the region “1” that is a region just before the region “0” at which the hour hand has stopped. Thus, the CPU3performs the date indicator driving in the case of the route “i” because the hour hand moves from the detection region “2” to the detection region “6” and beyond the hour hand detection regions “3” and “4” corresponding to the 12 o'clock (midnight) position, but does not perform the date indicator driving in the case of the route “ii” because the hour hand moves from the detection region “2” to the detection region “1” and this movement does not correspond to the date indicator driving condition. Descriptions of the other cases are omitted because the operations overlap with those in the above-mentioned case. In any case, the date indicator driving processing can be performed easily and accurately by the above-mentioned processing method for the region

Specific Description of the Second Embodiment

FIG. 10is a block diagram illustrating an exemplary hand position information circuit2according to the second embodiment.

The feature of the circuit configuration according to the second embodiment resides in that a circuit for performing the above-mentioned processing on the region “0” shown inFIGS. 9B and 9Dis added to the circuit of the first embodiment.

First and second 0-position determination circuits120and121, each being a circuit for determining whether or not the position of the hour hand is in the region “0”, are provided in the start circuit150and the stop circuit151, respectively, so as to detect the movement start from the region “0” and the stop in the region “0”.

When the movement start from the region “0” is detected, as described with reference toFIGS. 9B and 9D, the data on the region next to the region where the hour hand has started to move needs to be set as data of the start position holding register111.

As described above, the first and second stop registers102and103do not operate until the detection of the movement start of the hour hand203is detected, and hence the second stop register103stores data on a region where the hour hand203has stopped last time, that is, data on a region where the hour hand203has started to move this time. At the timing when the movement of the hour hand203is detected, data on a region next to the region where the hour hand has started to move is held in the first start register101. Thus, when the hour hand203starts to move from the region “0”, the data to be fetched into the start position holding register111is switched from the data on the region where the hour hand203has started to move to the data on the next region, and is held as start position holding data. Based on this data, the date indicator driving processing is performed by the CPU3.

When the hour hand203has started to move and stopped in the region “0”, a region before the hour hand has moved to the region “0” needs to be set as the data of the stop position holding register, and hence the registers for storing region data upon the change in region data output from the decode circuit1are provided as third and fourth stop registers115and116. In this manner, data on a region where the hour hand203is currently located is held in the third stop register115, and data on the previous region is held in the fourth stop register116. Thus, when the hour hand has stopped in the region “0”, the data on the previous region is selected and held in the stop position holding register112, and the date indicator driving processing can be performed by the CPU3based on this data.

When the hour hand has started to move and passed the region “0”, the same region data lasts for a while. In view of this, the stop determination circuit is configured to determine that the movement of the hour hand has stopped during the passage through the region “0”, and the processing for the case where the hour hand has stopped in the region “0” is performed. Subsequently, the hour hand moves from the region “0” to the next region, and hence the above-mentioned processing for the case where the movement start from the region “0” has been detected is performed. The processing for the case where the hour hand has passed the region “0” is described later. The above is the operation characteristic to the second embodiment.

Circuit Configuration in the Second Embodiment

The hand position information circuit2includes, in addition to the circuits ofFIG. 5, a first 0-position determination circuit120, a second 0-position determination circuit121, a start position selector130, a third stop register115, a fourth stop register116, and a stop position selector122. The other circuit configurations are the same, and hence the same configurations as those described above are denoted by the same reference numerals and the description thereof is omitted.

The difference between the circuits illustrated inFIG. 5andFIG. 10is described below. The output S1of the first start register101and the output S3of the second stop register103are input to the start position selector130, and an output S30of the start position selector130is input to the start position holding register111. The output S1of the first start register101is also input to the first 0-position determination circuit120. The first 0-position determination circuit120determines the input value of S1, and outputs a control signal S20that takes “1” when the value of S1is “0” and takes “0” otherwise. S20is input as a control line of the start position selector130. The input of the start position selector130is selected by the output S20of the first 0-position determination circuit, and the start position selector130selects S1when S20is “1” and S3when S20is “0”, and outputs the selected signal to the start position holding register111.

The output S2of the first stop register102is input to the stop flag circuit119and the second 0-position determination circuit121. The output S7of the stop determination circuit107is input to the control circuit105, the stop HR circuit110, and the second 0-position determination circuit121. The output SD of the decode circuit1is input to the first start register101, the first stop register102, and the third stop register115. The output S15of the third stop register is input to the fourth stop register116and the stop position selector122. The output S16of the fourth stop register is also input to the stop position selector122. The input of the stop position selector122is selected by the output S21of the second 0-position determination circuit121, and the second 0-position determination circuit121selects and outputs S16when S21is “1”, and selects and outputs S15when S21is “0”. The output S21of the second 0-position determination circuit121is set to be “1” when the input value of S2is determined to be “0”, and set to be “0” otherwise.

The output S191of the control circuit is input to the third stop register115and the fourth stop register116. In response to S191, the third stop register115and the fourth stop register116hold and output the respective input data. The configurations other than the parts described above are the same as those ofFIG. 5, and the operations thereof are also the same.

Description of the Operation in the Second Embodiment

Next, the circuit operation of the hand position information circuit2according to the second embodiment illustrated inFIG. 10is described with reference to flow charts ofFIGS. 11 and 12.FIG. 11illustrates a main routine, andFIG. 12illustrates a sub-routine illustrating the details of the “0”-region processing of the start position.

[1] Acquisition of the Movement Start Region of the Hour Hand

The first start register101holds the region data output from the decode circuit1at a change timing of the port clock SP (ST11-1). The movement detection circuit104compares the output S1of the first start register101and the output S3of the second stop register103(ST11-2). When the pieces of the region data are different from each other (ST11-2: NO), the movement detection circuit104determines that the hour hand203has started to move, and generates S4(ST11-3). When S1and S3are equal to each other (ST11-2: YES), the movement detection circuit104continues to compare S1and S3because there is no movement of the hour hand203. In this case, the output S3of the second stop register103is region data acquired when the hour hand moved to stop last time. The operation described above is the same as in the first embodiment.

[2] Movement Start Region Processing for the Region “0”

After the generation of S4indicating the detection of the movement start, a region “0” determination for the movement start position is performed (ST11-4). A description is now given with reference toFIG. 12.

The first 0-position determination circuit120determines whether or not the output S1of the first start register101is data on the region “0” (ST12-1). When the output S1is data on the region “0” (ST12-1: YES), the first 0-position determination circuit120sets S20to “1”, and otherwise (ST12-1: NO), sets S20to “0”, and outputs S20to select input data of the start position selector130. When S20is “1” (ST12-1: YES), the output S1of the first start register101indicating data on the region at which the hour hand arrives next to the region “0” is selected (ST12-3), and is held in the start position holding register111. When S20is “0” (ST12-1: NO), the output S3of the second stop register103indicating the region from which the hour hand has started to move is held in the start position holding register111(ST12-2).

In response to the generation of S5for operating the start position holding register111, the start HR circuit109generates S9to prompt the CPU3to acquire the data (ST12-4), and the CPU3fetches the region data S11of the start position holding register111(ST12-5).

[3] Acquisition of the Stop Region of the Hour Hand

Returning toFIG. 11again, in response to the generation of S4indicating the movement start detection of the hour hand203, the control circuit105generates the clock S8(ST11-5). At the change timing of S8, the control circuit105holds the region data SD of the decode circuit output1in the first stop register102(ST11-6), and simultaneously holds the output S2of the first stop register102in the second stop register103(ST11-7).

The stop flag circuit119compares S2and S3, which are respectively the outputs of the first stop register102and the second stop register103(ST11-8). When the outputs are equal to each other (ST11-8: YES), the stop flag circuit119sets S19to “1” (ST11-10). When the outputs are not equal to each other (ST11-8: NO), the stop flag circuit119sets S19to “0” (ST11-9).

The control circuit105generates the clock signal S191in accordance with the switching of the stop flag S19from “0” to “1”, and inputs the clock signal S191to the third stop register115and the fourth stop register116to permit the acquisition of the respective pieces of input data. Thus, if the data held by the third stop register is a detection region where the hour hand is currently located, data on a previous detection region is held in the fourth stop register (ST11-11).

When S19is continuously generated for a predetermined period of time (ST11-12: YES), the stop determination circuit107determines that the hour hand203has stopped, and S7becomes “1” (ST11-13). In response to the generation of S7indicating the stop of the hour hand, the control circuit105sets S6to “1” (ST11-14), and the stop position holding register112holds region data selected by the stop position selector122.

[4] Stop Processing for the Region “0”

The second 0-position determination circuit121determines whether or not the output S2of the first stop register102is data on the region “0” (ST11-15), and inputs the determination signal S21to the stop position selector122. When S21is “1” (ST11-15: YES), the stop position selector122selects the output S16of the fourth stop register116indicating the data on the previous detection region (ST11-16). When S21is “0” (ST11-15: NO), the stop position selector122selects the output S15of the third stop register115indicating the data on the detection region where the hour hand is currently located (ST11-17). In response to the generation of S7indicating the stop determination, the stop HR circuit110generates S10to prompt the CPU3to acquire the region data (ST11-18), and the CPU3fetches the region data S12of the stop position holding register112(ST11-19). The CPU3sequentially acquires the output S11of the start position holding register111and the output S12of the stop position holding register112, and determines that the hour hand has moved beyond the 12 o'clock (midnight) position.

The first stop register102and the second stop register103have the role of detecting the stop of the hour hand203, and hence fetch new region data SD until the stop determination is confirmed by the stop flag circuit119(S19, “1”). Thus, the first stop register102and the second stop register103cannot hold the region data corresponding to the stop position at the timing when S191is generated, and hence the third stop register115and the fourth stop register116are provided for holding the region data.

FIG. 13illustrates the operation of the hand position information circuit2shown inFIG. 10in the form of a time chart, illustrating the flow of data in time series. Note that, the time range marked with a line indicates an active “1”, and the time range not marked with a line indicates a negative “0”.

At a timing TM3inFIG. 13, the region data of the first start register101and the region data of the first stop register102are different from each other, and hence the output S4of the movement detection circuit104becomes “1”. At this time, the output S2of the first start register101is “2”, and hence the start position selector130outputs the output S2of the first start register101. The region data “2” of the second stop register output from the start position selector130is held in the start position holding register111, and is read by the CPU3.

Next, at TM4, the hour hand is located in the region “0”, and hence the first stop register102becomes “0” and the second stop register103also becomes “0” after one clock. Then, the stop flag circuit119becomes “1”. It is determined that the hour hand has stopped because the stop flag circuit119continues to output “1” for a predetermined period of time. However, because the region data of the first stop register102is “0”, the output of the second 0-position determination circuit121switches the stop position selector122to the fourth stop register116side at a timing TM5, and the region before the hour hand moves to the region “0” is held in the stop position holding register122and read by the CPU3.

The hour hand still continues to move thereafter, and the region data of the first start register101changes from “0” to “6”. Thus, the movement detection circuit104determines that the hour hand has started to move. However, the first 0-position determination circuit determines that the hour hand has started to move from the region “0”, and hence, at a timing TM6, the data S1of the first start register101is selected and held in the start position holding register111, which is then read by the CPU3.

The hour hand further continues to move, and stops in the region “4”. Then, because the stop flag is generated for a predetermined period of time or longer, the stop determination circuit107determines that the hour hand has stopped, selects the third stop register115serving as the current region data, and holds the region data in the stop position holding register112, which is read by the CPU3.

First Modified Example of the Second Embodiment

FIG. 14is a modified example ofFIG. 10, and the difference fromFIG. 10resides in that the input of the third stop register115is the output of the first stop register102. In this way, the third stop register115holds the output of the first stop register102that has already been synchronized with the port clock SP, and hence, when the output of the decode circuit1that operates in asynchronization with the hand position information circuit2is to be held, it is possible to prevent metastability that occurs when the clock and the data simultaneously change, thus further improving the certainty of the processing.

Second Modified Example of the Second Embodiment

FIG. 15is a second modified example ofFIG. 10. The difference fromFIG. 10resides in that the first, second, and third stop registers all operate with S8being the clock and that the input signals of the stop position selector122select the first stop register102and the third stop register115.

The third stop register115holds the output S3of the second stop register103, with the output S8of the control circuit105used as the clock. Then, the output S2of the first stop register102and the output S15of the third stop register115are input to the stop position selector122. The stop position selector122selects S15when the output S21of the second 0-position determination circuit121is “1”, and selects S2when S21is “0”, and then outputs the selected signal to the stop position holding register112.

Operation in the Second Modified Example of the Second Embodiment

The first, second, and third stop registers102,103, and115form a shift register, and hold the region data SD output from the decode circuit1in a serial manner. Both the outputs of the first and second stop registers102and103are compared with each other by the stop flag circuit119. When the outputs match with each other, the stop flag S19is generated. When the generation of S19continues for a predetermined period of time, the stop circuit107generates the stop determination S7.

In response to the generation of S7, the second 0-position determination circuit121selects the input of the selector122depending on whether or not the output S2of the first stop register102is the region “0” data. Specifically, when the second 0-position determination circuit121detects that the region data of S2is the region “0” data, the selector122selects the output S15of the third stop register115indicating the data on the region where the hour hand has been located before the hour hand enters the region “0”. Then, the control circuit105generates S6to fetch the region data S15into the stop position holding register112.

When the region data of S2is not the region “0” data, the stop position selector122selects S2indicating the data on the region where the hour hand is currently located. Then, the control circuit105generates S6to fetch the region data S2into the stop position holding register112. Note that, in this case, the second 0-position determination circuit121selects the input of the selector122in response to the generation of S7, but the second 0-position determination circuit121may select the input of the selector122always depending on whether or not S2is the region “0” data irrespective of the generation of S7. The other operations than the above are the same as the operations described with reference toFIG. 8.

Third Embodiment

FIG. 16illustrates a circuit configuration according to a third embodiment of the present invention. The difference fromFIG. 10resides in that the start HR circuit109is deleted and a second start position holding register113is added.

Even after entering the mode for correcting the hour hand, the CPU3performs the processing relating to the counting. When the CPU3receives the start HR signal S9or the stop HR signal S10described above from the hand position information circuit2, the CPU3interrupts the current processing and preferentially performs processing of reading the start position holding register111or the stop position holding register112from the hand position information circuit2. Thus, in order for the CPU3to efficiently perform the processing, it is desired that the number of processing interruptions by HR be small.

In the third embodiment, the start HR and the stop HR are not prepared separately, but the stop HR is used to read the region data of the start position holding register and the stop position holding register into the CPU3. This requires only one processing interruption by HR and a smaller number of signal lines for HR.

The second start position holding register113inputs the output S11of the start position holding register111, and in response to the output S6of the control circuit105, stores the data of S11and outputs the data to the CPU3. S6is the signal for controlling the stop position holding register112to hold stop region data of the hour hand. At the same timing as in the stop position holding register112, the second start position holding register113holds the output S11of the start position holding register111.

Operation in the Third Embodiment

In the example illustrated inFIG. 10, the movement start region data of the hour hand is held in the start position holding register111. In the example illustrated inFIG. 16, however, at the same timing when the movement stop region data is held in the stop position holding register112in response to the movement stop detection of the hour hand, the movement start region data is fetched from the start position holding register111into the second start position holding register113, and the acquisition request signal S10for the region data is issued from the stop HR circuit110to the CPU3. After that, the CPU3reads the data of the second start position holding register113and the stop position holding register112to perform the date indicator driving processing. The other operations than the above are the same as those described above with reference toFIG. 10. With this configuration, even if the movement of the hour hand203is restarted by a user's operation while the CPU3is reading the movement start region data and the movement stop region data described above, the movement start region data before the restart of movement can be held in the second start position holding register113and transferred to the CPU3, and further the movement start region data at the time when the hour hand is moved again can be held in the start position holding register111. Consequently, even if the user moves the hour hand again in the hour hand correction, the operational intension can be reflected to improve the convenience. In addition, the number of control lines used for communications between the CPU3and the hour hand position information circuit can be reduced, and further, the acquisition of the region data can be limited to one timing and hence the processing of the CPU3does not need to be interrupted frequently and the efficiency can be improved.

FIG. 17is a time chart illustrating the flow of data ofFIG. 16in time series. At TM11and TM12, the stop region data of the hour hand is held in the stop position holding register112and is read by the CPU3, but at the same timings, the data of the start position holding register111is read into the second start position holding register113. Thus, the CPU3can read the data of the start position and the stop position at once.

The stop determination circuit107is a circuit for determining that the movement of the hour hand has stopped when the region data output from the decode circuit remains unchanged for a predetermined period of time. The stop determination circuit107includes a timer for measuring a period during which the pieces of region data match with each other. As timer values, first timer data indicating a normal determination time and second timer data indicating a determination time longer than the first timer data are prepared. When the second timer data is selected, the time required for determining the stop of the hour hand becomes longer, and hence it is not determined that the hour hand has stopped even when the hour hand has stopped for a short time. Thus, even if a short stop occurs when the user is moving the hour hand, unnecessary date indicator driving processing is not performed. Changing the calendar display by the date indicator driving processing consumes large power, and hence, by selecting the second timer data under the condition to be described later such as a low power supply voltage, the frequency of the wasted date indicator driving processing can be reduced.

The stop determination circuit107includes a reset circuit107-12, a counter107-5, a comparator107-6, a stop determination holding circuit107-10, a storage unit107-11for storing first timer data107-7and second timer data107-8, and a selector107-9.

The output S19of the stop flag circuit119is input to an enable of the counter107-5and the reset circuit107-12, an output of the reset circuit107-12is input to a reset of the counter107-5, and an output of the counter107-5is input to the comparator107-6.

An output of a power supply voltage measurement circuit211is input to the CPU3, and a date indicator driving motor212is driven by a drive signal output from the CPU3. The storage unit107-11stores the first timer data107-7and the second timer data107-8. The timer data is selected by the selector107-9in response to a control signal of the CPU3, and is input to the comparator107-6. The output of the comparator107-6is input to the stop determination holding circuit107-10, and the output of the stop determination holding circuit107-10is input to the stop HR circuit110, the control circuit105, and the second 0-position determination circuit121as S7.

[Operation of the Stop Determination Circuit]

Next, a description is given of the operation of the stop determination circuit107illustrated inFIG. 18. In this case, first, a description is given of the output signal S19of the stop flag circuit119in the hand position information circuit2ofFIG. 10.

When the movement detection circuit104illustrated inFIG. 10detects the movement of the hour hand, S8is generated and the first stop register102and the second stop register103hold the region data output from the decode circuit1in a serial manner. The first stop register and the second stop register are shift registers that operate with a common clock. When position region data of the output of the decode circuit has changed, the value of the first stop register and the value of the second stop register differ from each other by one clock. When there is no change, the values are identical to each other.

The stop flag circuit119compares the first stop register102and the second stop register103to detect that the pieces of position region data match with each other, and the stop flag S19continues to output “1” as long as the stop register1and the second stop register have the same value.

Next, a description is given of the operation of the stop determination circuit107with reference to a flow chart ofFIG. 20. It is determined whether or not S19of the stop flag circuit is “1”, that is, whether or not the hour hand is brought into the stop state (ST20-1). When S19is “1” (ST20-1: YES), the counter107-5executes the counting (ST20-2). Note that, the specific configuration of the counter107-5and the clock for counting are not essential parts of the present invention and are therefore omitted, but may be freely selected as long as the present invention can be realized.

Next, a timer value preset in the storage unit107-11and the value of the counter107-5are compared to each other (ST20-3), and, when those values become equal to each other (ST20-3: YES), it is determined that the hour hand has stopped, and S7is generated (ST20-4). Note that, when S19is “0” (ST20-1: NO), the counter107-5is cleared by the reset circuit107-12, and the stop of the hour hand is continued (ST20-5).

In the storage unit107-11, a plurality of pieces of timer setting data are prepared. The first timer data107-7sets a normal stop determination time, and the second timer data107-8sets a stop determination time longer than the first timer data. The longer stop determination time as used herein refers to a period that is 1.5 times to 2 times the normal stop determination time, for example. The normal stop determination time as used herein refers to a period suitable for the stop determination that is acquired based on the rotation speed of the hour hand in the correction operation or the clock frequency of the hand position information circuit2.

[Selection Condition of the Second Timer]

Referring toFIG. 21, a description is given of selection processing for the first timer data107-7and the second timer data107-8in the storage unit107-11.

FIG. 21is a flow chart illustrating the selection processing for the above-mentioned timer values.

First, it is determined whether or not the date indicator driving motor212is driven for driving the day dial (ST21-1). When the date indicator driving motor212is driven (ST21-1: YES), the second timer data is selected as the timer value (ST21-4).

When the date indicator driving motor212is not driven (ST21-1: NO), it is determined by the power supply voltage measurement circuit211whether or not a battery voltage is lower than a prescribed value (ST21-2). When the battery voltage is lower than the prescribed value (ST21-2: YES), the second timer data is selected as the timer value (ST21-4), and otherwise (ST21-2: NO), the first timer data is selected as the timer value (ST21-3).

The date indicator driving processing is performed when the correction operation of the hour hand position is performed by the user to move the hour hand beyond the 12 o'clock (midnight) position and stop the hour hand. However, it takes time to complete the date indicator driving operation.

In the date indicator driving processing, for example, even if the hour hand is moved again beyond the 12 o'clock (midnight) position by the correction operation during the date indicator driving processing and if the movement of the crown operation is stopped by an operator's operation so that the hour hand stops for a short time, by selecting the second timer data107-8, the stop determination time becomes longer, and hence the hour hand position information circuit107is less likely to determine that the hour hand has stopped. Thus, the CPU3can be reduced in frequency of receiving the start HR signal S9and the stop HR signal S10that request the reading processing from the hour hand position information circuit107during the date indicator driving processing, and hence the load on the CPU3can be reduced.

Further, in the case where the user repeats a reciprocating operation of the hour hand to move the hour hand beyond the 12 o'clock (midnight) position continuously, a determination that the hour hand has stopped for a short time occurs at the moment when the movement direction of the hour hand is changed, and the CPU3receives the stop HR signal S10. Thus, the date indicator driving processing occurs correspondingly to the reciprocation of the hour hand, and the time-consuming operations of the date indicator driving and the date indicator reverse driving are repeated unnecessarily. By selecting the second timer data107-8, the CPU3does not respond to the short stop of the hour hand during the date indicator driving processing, and hence the date indicator driving processing can be minimized to prevent wasted power consumption.

In addition, also in the case where the power supply voltage is measured by the power supply voltage measurement circuit211to be lower than a prescribed voltage or less, the CPU3selects the second timer data. In the date indicator driving processing, the pulse is continuously driven for the date indicator driving motor, and hence the power is consumed. If the date indicator driving is continuously repeated under the state in which the power supply voltage is low, there is a fear that the voltage is further reduced to be lower than a minimum operation voltage of the system. Thus, in the period during which the power supply voltage is low, the second timer data107-8is selected to set a longer stop determination time so that the CPU3is prevented from responding to an instantaneous operation stop during the user's operation of the hour hand, to thereby minimize the continuous date indicator driving. In this manner, the number of processing of the CPU3can also be reduced to suppress the reduction in power. Further, the CPU3may select the second timer data107-8in the period during which a heavy load function involving the reduction in power supply such as the hand position detection circuit203operates. Alternatively, the second timer data may be selected from the beginning by the setting by the user irrespective of the condition. In this manner, a timer time suitable for the user's feeling of operation can be set. Note that, in this case, when three or more timer values are prepared for selection, fine adjustment for the user's feeling of operation can be made.

Modified Example of the Stop Determination Circuit

FIG. 19is a modified example of the circuit ofFIG. 18.FIG. 19is different fromFIG. 18in the configuration from the input S19to the counter circuit. Specifically, a stop flag rising detection circuit107-1, a stop flag falling detection circuit107-2, and a start circuit107-3are added.

The output S19of the stop flag circuit is input to the stop flag rising detection circuit107-1and the stop flag falling detection circuit107-2, and an output of the stop flag rising detection circuit is input to the start circuit107-3. Further, an output of the stop flag falling detection circuit is input to the start circuit and a reset of the counter107-5. An output of the start circuit is input to an enable of the counter, and an output of the counter is input to the comparator107-6. As described above, by detecting the leading edge of the output S19of the stop flag circuit119and by turning on the start circuit107-3to operate the counter107-5, the following advantage occurs. That is, the stop flag circuit119is formed of a combinational circuit such as an exclusive OR, and hence a hazard is liable to occur upon the switching of the input signal. If the hazard propagates to an enable signal for controlling the operation of the counter107-5, the reliability of the counter value is lowered. On the other hand, by producing a start signal synchronized with a clock in accordance with an ON duration of the stop flag signal S19as illustrated inFIG. 19and by inputting the start signal to the enable of the counter, an erroneous operation of the counter can be prevented without being affected by the hazard of the stop flag signal.

Fourth Embodiment

A fourth embodiment of the present invention is described with reference toFIG. 22. In the fourth embodiment, a stop determination period of the stop determination circuit107in the hand position information circuit2is set to be shorter than a time required for the hour hand to pass the region “0”. In this manner, each time the hour hand passes the region “0”, the stop determination occurs during the passing through the region “0”.

Part (a) ofFIG. 22is an example of the hour hand movement. In order to show the effect of the above-mentioned stop determination period setting method, parts (b) and (c) ofFIG. 22illustrate how the position region data of the start position holding register111and the stop position holding register112differs depending on whether or not the above-mentioned stop determination period setting method is performed. In part (a) ofFIG. 22, reference numeral221-1represents the rotation direction of the hour hand;221-2, the movement start position of the hour hand; and221-3, the stop position of the hour hand. The hour hand position in the diagrams of parts (b) and (c) shows the region data output from the decode circuit1in the course of the movement of the hour hand in the form of a time-series transition from the left to the right. Numerical values of the start position holding register and the stop position holding register shown inFIG. 22represent the pieces of region data of the hour hand position that are acquired by the start position holding register111and the stop position holding register112along with the above-mentioned operation described in the second embodiment. t1represents the stop determination time of the stop determination circuit107. Part (b) shows the region data of the start position holding register and the stop position holding register acquired in the case where the stop determination period setting method is not performed, that is, in the case where the stop determination time t1is longer than the time required for the hour hand to pass the region “0”. On the other hand, part (c) shows the region data of the start position holding register and the stop position holding register acquired in the case where the stop determination period setting method is performed, that is, in the case where the stop determination time t1is shorter than the time required for the hour hand to pass the region “0”. In the example of part (a) ofFIG. 22, the hour hand moves in the order of the regions “5”, “4”, “3”, “2”, “1”, “0”, and “6”, and the region “5” is held in the start position holding register111.

In part (b) ofFIG. 22, the above-mentioned stop determination time setting method is not performed, and hence the stop determination period t1is larger than the region “0” passage time, and the stop determination is not made within the time during which the hour hand passes the region “0”. The hour hand thereafter passes the region “0” and stops in “6”. Thus, the start position holding register holds “6” indicating the region next to the region “0”, and the stop position holding register112holds the region “6” where the hour hand has stopped, which are fetched into the CPU3. Accordingly, the CPU3erroneously recognizes that the hour hand has moved from “5” to “6”, and hence does not perform the date indicator driving (date indicator reverse driving) processing. In other words, despite the fact that the hour hand203has moved beyond the 12 o'clock (midnight) position, it is erroneously determined not to perform the date indicator driving (date indicator reverse driving) processing.

On the other hand, in part (c) ofFIG. 22, the above-mentioned stop determination period setting method is performed, and hence the stop determination time t1is smaller than the region “0” passage time of the hour hand, and the stop determination is surely made while the hour hand is passing the region “0”.

Operation in the Fourth Embodiment

Next, a description is given of the operation. When the hour hand starts to move, the region “5” is held in the start position holding register111. When the hour hand continues to move and enters the region “0”, the position region data remains unchanged for a while, and hence the stop flag circuit119continues to generate S19. In the stop determination circuit107, the stop determination time t1is smaller than the region “0” passage time, and hence a stop determination occurs during the passage through the region “0”. Then, by the region “0” processing described in the second embodiment, “1” indicating one region before the region “0” is held in the stop position holding register112and fetched into the CPU3. The CPU3performs the date indicator driving (date indicator reverse driving) processing because the hour hand has moved from the region “5” to the region “1”.

After that, the hour hand moves from the region “0” to the region “6”, and hence, based on the region “0” processing described in the second embodiment, “6” indicating the region next to the region “0” is held in the start position holding register111. When the hour hand further continues to move and stops in the region “5”, the region “5” is held in the stop position holding register112and fetched into the CPU3. Accordingly, the CPU3does not perform the date indicator driving (date indicator reverse driving) processing because the hour hand has moved from “6” to “5”. Consequently, even when the hour hand has passed the region “0” and moved beyond the 12 o'clock (midnight) position, the date indicator driving processing can be reliably performed.

[Method of Setting the Stop Determination Time t1]

FIG. 23illustrates a method of setting the stop determination time t1according to the fourth embodiment.FIG. 23illustrates how to set a minimum value and a maximum value of the stop determination time t1in order to define the stop determination time t1so that a stop determination is reliably made during the passage of the hour hand through the region “0”. Part (a) shows the minimum value of the stop determination period t1, and part (b) shows the maximum value of the stop determination period t1. Part (1) shows a movement route of the hour hand and the stop determination time, and part (2) shows the region data output from the decode circuit1along with the movement of the hour hand in chronological order from left to right.

The output of the decode circuit1is asynchronous with a change timing of the port clock SP of the hand position information circuit2, and hence the holding timing of the hour hand position information circuit is not constant with respect to the change timing of the decoded signal. An error time Δt is a time taking this time fluctuation into account, and may be, for example, a longer one of a time corresponding to two periods of the hour hand motor driving pulse and a time corresponding to two periods of the port clock. t2is a time required for the hour hand to pass the region “0”, and t3is a processing estimated time of the CPU3. t4is the longest one of the times required for the hour hand to pass the respective regions “1” to “6”. In the case where the respective regions “1” to “6” have equal intervals, any passage time for the regions may be set. InFIG. 23, reference numeral222-1represents the movement start position of the hour hand;222-2, the stop position of the hour hand;222-3, a stop determination position when t1is the minimum value;222-4, the rotation direction of the hour hand; and222-5, an hour hand position when t1is the maximum value.

For parts (a) and (b) ofFIG. 23both, a description is given with the assumption that the hour hand has moved in the order of the regions “2”, “1”, “0”, and “6”. Part (a) ofFIG. 23illustrates the minimum value of the stop determination time t1, in which the stop determination time t1is set to a period acquired by adding t4to an error time Δt. In this case, the stop determination circuit107quickly determines the stop of the hour hand when the passage time of one region and the error time have elapsed since the hour hand entered the region “0”, and then the hand position information circuit2transmits the data of the stop position holding register112to the CPU3. The CPU3can finish the date indicator driving processing well in advance by the time the hour hand arrives at the region “6”, and hence, even when the hour hand enters the region “6” and the movement detection circuit105sets the movement start signal S4to “1” to prompt the CPU3to fetch the data of the start position holding register111, the CPU3can immediately respond to the prompt. Consequently, the acquisition of the stop position holding register112, which is the next process, and the date indicator driving processing can be performed without any delay.

Part (b) ofFIG. 23shows the maximum value of the stop determination time t1, and the stop determination time t1is set to a time acquired by subtracting a CPU processing estimated time t3from the time t2during which the hour hand passes the overall width of the region “0”. In this manner, the date indicator driving processing of the CPU3can reliably be finished by the time the hour hand arrives at the detection region “6”, and further, the stop determination time can be lengthened as much as possible. Consequently, the CPU3can be prevented from easily responding to the short stop of the hour hand during the user's operation of the hour hand, and hence the date indicator driving processing can be minimized to prevent wasted power consumption.