JP2001195178A - Position coordinate data communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a position coordinate data communication system which is free from confusion of data wherein a batch processing of pieces of data transmitted from plural coordinate readers are performed by a computer. SOLUTION: The computer transmits different initial values to respective counters provided to each of n coordinate readers. For the purpose, a value formed by summing a counter value C and an integer value obtained by rounding up a first decimal number of the data packet transmission time tp divided by count time interval tc of a counter is set as a new counter value C and transmitted to the coordinate reader in a step S110 (S104). These processings are repeated for n times. Thus, the pieces of data transmitted from each coordinate reader are free from confusion in the computer since transmission timings of each coordinate reader are different and intervals of the transmission timings become equal to or longer than the data packet transmission time tp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate reading device for reading the position coordinates of a coordinate input device on a coordinate input surface by utilizing magnetic coupling generated between the coordinate input device and the coordinate input surface, and a coordinate reading device for reading the coordinates. The present invention relates to a position coordinate data communication system including an information processing device capable of communicating with a plurality of reading devices.

[0002]

2. Description of the Related Art Conventionally, as the above coordinate reading device, for example, a coordinate input board in which a plurality of loop-shaped coils are arranged below a coordinate input surface in the X-axis and Y-axis directions, and a coil for generating an alternating magnetic field are incorporated. A device provided with a coordinate input pen is known. In this coordinate reading device, an alternating magnetic field generated from a coordinate input pen placed on a coordinate input surface induces a voltage in a loop-shaped coil arranged below the coordinate input surface, and the coordinate input pen is set based on the voltage value. The position coordinates of are detected. The coordinate reading device can output the detected position coordinates to the outside. For example, the coordinate reading device can output the detected position coordinates to a printer and print the position coordinates on a sheet.

[0003]

SUMMARY OF THE INVENTION The present inventors have considered a communication system in which a plurality of the coordinate reading apparatuses described above are connected to a computer via a communication line, and position coordinates are transmitted from each coordinate reading apparatus to the computer. For example, in a school class, multiple students each use a coordinate reader,
When a teacher uses a computer connected to each coordinate reading device by a communication line, data written by each student on the coordinate reading device is transmitted to the teacher's computer via the communication line, and the teacher looks at the computer monitor. This is a communication system that allows students to know the contents written. However, since the conventional coordinate reading device is a method of sequentially outputting data input by a coordinate input pen, if data is to be collectively processed by a computer from a plurality of coordinate reading devices, the data is confused and the data is lost. It turned out that there was a problem of missing.

Therefore, the present invention has been made to solve the above-mentioned problem, and when data transmitted from a plurality of coordinate reading devices is collectively processed by a computer, data confusion does not occur. An object is to realize a position coordinate data communication system.

[0005]

Means for Solving the Problems, Functions and Effects of the Invention
According to the present invention, in order to achieve the above object, in the inventions described in claims 1 to 8, the magnetic coupling generated between the coordinate input means and the coordinate input surface is utilized, and the magnetic coupling on the coordinate input surface is performed. A coordinate reading device for reading the position coordinates of the coordinate input means; and an information processing device capable of communicating with a plurality of the coordinate reading devices, wherein the coordinate reading device transmits position coordinate data indicating the read position coordinates to a predetermined position. A transmission unit that transmits the coordinate reading device to the information processing device at a timing, and the information processing device includes a control unit that controls the coordinate reading device so that the predetermined timing differs for each of the coordinate reading devices. Use strategic means.

The control means provided in the information processing device controls the coordinate reading device such that the predetermined timing at which the coordinate reading device transmits the position coordinate data to the information processing device differs for each coordinate reading device. That is, since the timing at which the coordinate reading device transmits the position coordinate data to the information processing device can be controlled so as to be different for each coordinate reading device, when a plurality of coordinate reading devices transmit the position coordinate data to the information processing device, However, there is no possibility that the position coordinate data is confused in the information processing device.

According to a second aspect of the present invention, in the position coordinate data communication system according to the first aspect, the coordinate reading device includes a measuring means for measuring a time until the predetermined timing is reached, The control means uses a technical means that the time set for each of the coordinate reading devices can be set differently.

That is, the coordinate reading device is provided with measuring means for measuring the time until a predetermined timing is reached, and the time is set differently for each coordinate reading device by the control means. Transmits the position coordinate data to the information processing device at different timings. Therefore, there is no possibility that confusion of position coordinate data that occurs when each coordinate reading device transmits position coordinates to the information processing device at the same timing occurs in the information processing device.

According to a third aspect of the present invention, in the position coordinate data communication system according to the first or second aspect, the predetermined timing set in the first coordinate reading device and the second coordinate are set. A technical means is used in which the difference from the predetermined timing set in the reading device is at least the time required for transmitting the position coordinate data.

That is, if a plurality of coordinate reading devices transmit position coordinate data at intervals shorter than the time required for transmitting the position coordinate data, confusion of the position coordinate data may occur. By transmitting the coordinate data at intervals longer than the time required for transmitting the coordinate data, confusion of the position coordinate data can be eliminated.

According to a fourth aspect of the present invention, in the position coordinate data communication system according to any one of the first to third aspects, the transmitting means changes each time the position coordinate data is transmitted. Technical means of transmitting data to the information processing device together with the position coordinate data is used.

That is, if position coordinate data is transmitted a plurality of times from the same coordinate reading device, the information processing device may not be able to distinguish between the received plurality of position coordinate data. By transmitting the data that changes each time is transmitted together with the position coordinate data, the information processing apparatus can identify between the position coordinate data based on the received changing data.

According to a fifth aspect of the present invention, in the position coordinate data communication system according to any one of the first to fourth aspects, the transmission means transmits the position coordinate data when transmitting the position coordinate data. While monitoring the position coordinate data communicated by the communication unit that connects the reading device and the information processing device, if the monitored position coordinate data is different from the position coordinate data transmitted by itself, A technical means of waiting for transmission of the position coordinate data until the transmission is completed is used.

That is, if the length of the position coordinate data to be transmitted differs between the coordinate reading devices, even if the transmission timing is different between the coordinate reading devices, a certain coordinate reading device transmits the position coordinate data. It is assumed that another coordinate reading device starts transmitting the position coordinate data before the end, and the position coordinate data is confused. Therefore, when transmitting the position coordinate data, the position coordinate data communicated by the communication means is monitored, and when the monitored position coordinate data is different from the position coordinate data transmitted by the self,
Since the other coordinate reading device is transmitting the position coordinate data, in such a case, by waiting for the transmission of the position coordinate data until the next transmission timing,
The confusion of the position coordinate data can be eliminated.

According to a sixth aspect of the present invention, in the position coordinate data communication system according to any one of the first to fifth aspects, the transmitting means transmits the position coordinate data to the information processing by packet communication. Use the technical means of transmitting to the device.

That is, by transmitting the position coordinate data to the information processing device by packet communication, a plurality of coordinate reading devices can be connected to a common communication line, so that the cost required for the communication line can be reduced.

According to a seventh aspect of the present invention, in the position coordinate data communication system according to any one of the first to sixth aspects, the transmitting means includes an identification for identifying the coordinate reading devices. A technical means of transmitting the position coordinate data to the information processing device together with the data is used.

That is, even when the position coordinate data is transmitted from a plurality of coordinate reading devices, the information processing device receives the identification data transmitted together with the position coordinates, and based on the identification data, receives the position coordinate data. The source of the data can be specified.

According to an eighth aspect of the present invention, in the position coordinate data communication system according to any one of the first to seventh aspects, the transmitting means indicates when the position coordinate data was transmitted. A technical means of transmitting the position coordinate data to the information processing device together with the data is used.

That is, by transmitting the position coordinate data to the information processing device together with the data indicating when the coordinate reading device has transmitted the position coordinate data,
It is possible to recognize when the received position coordinate data has been transmitted.

[0021]

[First Embodiment] A first embodiment of a position coordinate data communication system according to the present invention will be described below with reference to the drawings. In each of the embodiments described below, a so-called coordinate reading device, which electrically reads handwritten characters and figures drawn on a coordinate input sheet, is used as a coordinate reading device used in the position coordinate data communication system according to the present invention. This will be described using an example. In addition, a desk-top coordinate reading device will be described as an example of the coordinate reading device.

[Main Configuration of Coordinate Reading Apparatus] First, the first
A main configuration of the coordinate reading device according to the embodiment will be described with reference to FIG. FIG. 1A is a perspective explanatory view of a coordinate reading device according to the first embodiment, and FIG.
It is explanatory drawing which looked at the coordinate reader shown in (A) from the back. The coordinate reading device A1 includes a writing panel 10, a pen 60 for writing on the writing surface 21a, and an eraser 40 for erasing the written locus and data indicating the locus. The writing panel 10 includes a frame 11 having a frame shape, and the writing panel main body 20 is incorporated in the frame 11. An operation unit 30 is provided on the right side of the front surface of the frame 11. The operation unit 30 includes a speaker 31 for reproducing sounds such as an operation sound and a warning sound, and a seven-segment page number storing data indicating the contents written on the writing surface 21a (hereinafter referred to as writing data). A page number display LED 32 displayed by an LED, a page return button 33 that returns one page each time the button is pressed, a page forward button 34 that advances one page each time the button is pressed, and one page each time the stored writing data is pressed. Button 35, a print button 36 pressed to output stored writing data to a printer (not shown), and an output button pressed to output stored writing data to computer B (FIG. 2). A button 37, an LED 39 for notifying that the battery of the pen 60 has run out, and an LED 39 for starting or stopping the coordinate reader A1. A power button 38 is pressed is provided.

As shown in FIG. 1B, a battery case 14 for accommodating four C-size batteries 14a serving as a power source of the coordinate reading device A1 is provided on the back of the frame 11. 14 has a lid 14b
Is mounted to be openable and closable. On the right side of the battery case 14, a volume adjustment knob 13c for adjusting the volume of the speaker 31 is provided. On the right side, a connector 13b for connecting to a printer and a connector for connecting the data transmission line L1 (FIG. 2). 13a. That is, handwriting data indicating the contents written on the writing surface 21a of the coordinate reading device A1 is transmitted to the computer B via the data transmission line L1, and the coordinate reading device is provided by the display 88 (FIG. 4) provided in the computer B. A
You can see the contents written in 1. In addition, it is also possible to output handwriting data to a printer and print the contents handwritten on the coordinate reading device A1 on printing paper. The pen 60 and the eraser 40 each include a coil for generating an alternating magnetic field, an oscillation circuit for oscillating the coil, a battery for driving the oscillation circuit, and the like.

[Configuration of Network] Next, the configuration of a network in the case where data communication is performed between a plurality of coordinate reading apparatuses and the computer B will be described with reference to FIG. Here, a case where a class is conducted in a school will be described as an example. Also, each student uses a coordinate reading device, and each coordinate reading device and LA
It is assumed that the teacher uses a computer connected by N lines. The position coordinate data communication system 1 includes coordinate reading devices A1 to An used by each student, and the coordinate reading devices A1 to An are connected to the HUB 12 by data transmission lines L1 to Ln, respectively.
The HUB 12 is connected to a computer B used by the teacher via a data transmission line Lb. Then, the handwritten data written on the coordinate reading devices A1 to An with the pen 60 is transmitted from the data transmission lines L1 to Ln to the computer B via the HUB 12 and the data transmission line Lb. The writing data generated in each of the coordinate reading devices A1 to An is formed into a data packet, and transmitted to the computer B as data packets D1 to Dn. For example, when the character "G" is written on the coordinate reading device A1, the display 88 connected to the computer B
Displays the letter "G".

[Main Electrical Configuration of Coordinate Reading Apparatus]
A main electrical configuration of the coordinate reading device will be described with reference to FIG. Here, the coordinate reading device A
1 will be described as an example. The coordinate reading device includes an X coil switching circuit 50a that sequentially switches the X coils for detecting the X coordinates in the loop-shaped coil group 23, and a Y coil switching circuit 50b that sequentially switches the Y coils for detecting the Y coordinates. Is provided. The ROM 58 stores a position coordinate table in which voltage values and position coordinates are associated with each other, a computer program for calculating the position coordinates, a computer program for converting writing data including the calculated position coordinates into data packets, and the like. ing. Also, RA
M59 temporarily stores the computer program read from ROM 58, the calculation result of CPU 56, and the like.

The alternating magnetic field generated from pen 60 causes X
The signal of the predetermined voltage induced in the coil and the Y coil is
The amplified signal is amplified by the amplifier 50c, and an unnecessary band of the amplified signal is filtered by a band pass filter (BPF) 50d, and the amplitude is detected by an amplitude detection circuit 51. Subsequently, the amplitude-detected signal is converted into a digital signal corresponding to the amplitude, that is, the voltage value by the A / D conversion circuit 52, and is input to the CPU 56 via the input / output circuit 53. Then, the CPU 56 calculates the position coordinates of the pen 60 based on the input digital signal while executing the computer program. The signal output from the bandpass filter 50 d is converted into a square wave limiter output signal by the limiter circuit 54 and output to the FSK demodulation circuit 55. And the FSK demodulation circuit 55
The count value of the square wave of the input limiter output signal is output to the CPU 56, and the CPU 56 determines pen attributes such as the color of the ink of the pen 60 and the thickness of the pen tip based on the count value.

The counter 70 connected to the CPU 56
The timing of transmitting a data packet from the coordinate reading device A1 to the computer B is counted. The initial value of the count value is obtained from the computer B via the data transmission line L.
1, received via the LAN board 71 and the interface 57, and set in the counter 70. That is,
The transmission timing of the data packet is controlled by the computer B. Also, the interface 57 includes:
An audio circuit 31a for reproducing a speaker is connected.

[Main Electrical Configuration of Computer]
The main electrical configuration of the computer B will be described with reference to FIG. Computer B has a CPU 8
1, a RAM 83, a ROM 82, a timer 89, a hard disk drive unit (hereinafter referred to as HDD) 90, an interface 84, and a LAN board 85.
The CPU 81 controls an initial value of a counter 70 provided in each of the coordinate reading devices A1 to An, and controls each of the coordinate reading devices A1 to A.
n, a process of receiving the data packet transmitted from n, a process of converting the received data packet into data that can be displayed on the display 88, and the like. The HDD 90 has a CP
A computer program for the U81 to execute the above various controls and processes is stored, and a computer program for starting up the computer B and the like are stored in the ROM. RAM 83 is HDD 9
0 and the computer program read from the ROM 82 and the processing results of the CPU 81 are temporarily stored.
The timer 89 is controlled by the CPU 81 so that each of the coordinate reading devices A1 to An
The transmission interval such as the initial value of the counter to be transmitted to is counted.
The computer B has a keyboard 86 and a mouse 8
7 and the display 88 are connected.

[Main Structure of Data Packet] FIG. 5A shows the main structure of a data packet.
This will be described with reference to FIG. Here, the data packet D transmitted from the data packet A1 to the computer B is
1 will be described as an example. The data packet D1 includes a header D1a indicating a start flag and the like, and each of the coordinate reading devices A1 to A1.
An identification code D1b for identifying Ans, date and time data D1c indicating the date and time when the data packet D1 was transmitted, data length data D1d indicating the amount of data length, and writing data D
1e and a footer D1f indicating an error code or the like. Then, the data packets transmitted from each of the coordinate reading devices A1 to An are stored for each identification code as shown in FIG. 5C for explaining the configuration of the data packets stored in the HDD 90. As described above, since the identification code is attached to the handwritten data, the computer B is configured as shown in FIG.
As shown in (C), a data packet can be stored for each identification code. In addition, when the writing data is displayed on the display 88, by displaying the identification code, it is possible to recognize who the student transmitted.
In this case, by storing a table in which the identification codes are associated with the student names in the HDD 90, the student names can be displayed on the display 88. Further, since the date and time data is attached to the handwritten data, the computer B can recognize when the data packet is transmitted. Further, the history of data packets can be managed.

[Communication Flow] Next, each coordinate reading device A1
The communication flow performed between .about.An and the computer B will be described with reference to FIGS. FIG. 6 is a flowchart showing a main processing flow of the computer B, and FIG. 7 is a flowchart showing the steps performed by the computer B in FIG.
FIG. 8 is a flowchart showing the flow of the counter control executed in 100. FIG.
4 is a flowchart illustrating a flow of a data reception process executed in the first embodiment; FIG. 9 is a flowchart showing a main processing flow of the coordinate reading apparatus, FIG. 10 is a flowchart showing a flow of an initial value receiving process executed by the coordinate reading apparatus in S500 of FIG. 9, and FIG. Is S in FIG.
6 is a flowchart showing a flow of a data transmission process executed in 700.

(Main Process Flow of Computer B) First, the main process flow of computer B will be described with reference to FIG. The computer B has a coordinate reading device A
The counter control (S100) for controlling the initial value of the counter 70 (FIG. 3) provided in each of the coordinate reading devices A1 to An, and the data packets D1 to Dn transmitted from each of the coordinate reading devices A1 to An are received and stored in the HDD 90. (S200) and a data editing process of reading data stored in the HDD 90 and converting the data into data that can be displayed on the display 88, and editing the data by operating the keyboard 86 and the mouse 87. (S30
0).

(Main Process Flow of Coordinate Reading Apparatus)
The main processing flow of the coordinate reading device will be described with reference to FIG. The coordinate reading device receives the initial value of the counter transmitted from the computer B and sets the initial value in the counter 70 (FIG. 3) (S30).
500), a coordinate reading process (S600), and a data transmission process (S700) for converting the handwritten data into data packets and transmitting them to the computer B.

(Counter Control and Initial Value Receiving Process) Next, the counter control executed by the computer B (S10
The flow of 0) and the initial value receiving process executed by the coordinate reading device will be described with reference to FIGS. The computer B sets the counter value C to be transmitted first to the coordinate reading device A1 to an initial value, and executes S104 until the counter control is executed for the last coordinate reading device An.
A loop count value m indicating how many times the loop process from S110 to S110 is executed is set to an initial value “1” (S10 in FIG. 7).
2). Subsequently, the computer B transmits an initial value as a counter value to the first coordinate reading device A1 (S10).
4). Then, the coordinate reading device receives the initial value transmitted from the computer B (S502 in FIG. 10), sets the received initial value in the counter 70 (S504), and waits until a count start signal is transmitted from the computer B. It waits (S506).

Then, the computer B sets the loop count value m
Is incremented by 1 (S106), and if the loop count value m is not equal to the total number n of coordinate reading devices (S108: No), the time required for the coordinate reading device to transmit a data packet (hereinafter referred to as data A value obtained by adding a counter value C to an integer value obtained by rounding up the first decimal place of a value obtained by dividing tp by a count time interval tc of the counter 70 (referred to as a packet transmission time) is set as a new counter value C ( S110). For example, tp = 10μ
sec, tc = 3 μsec, tp / tc =
Since 10/3 = 3.33..., A value obtained by adding the integer value 4 obtained by rounding up the first decimal place and the counter value C is set as a new counter value C (S1).
10).

That is, for example, the difference between the initial value transmitted to the coordinate reading device A1 and the initial value transmitted to the coordinate reading device A2 is, for example, 6 μsec, and 6 μsec has elapsed since the coordinate reading device A1 transmitted the data packet. At this time, if the coordinate reading device A2 transmits a data packet, the data packet transmission time tp is 10 μsec.
Before the coordinate reading device A1 finishes transmitting the data packet, the transmission of the data packet from the coordinate reading device A2 is started, and the data packets transmitted from both collide in the data transmission line. A problem arises that the data packets are confused. Therefore, in order to prevent such a problem from occurring, each of the coordinate reading devices A1 to A
n so that the interval between the initial values to be transmitted to n is longer than at least the data packet transmission time (S11).
0).

Subsequently, the computer B transmits the counter value set in S110 to the second coordinate reading device A2 (S104). Then, the coordinate reading device A2 executes the same processing as the coordinate reading device A1, and the computer B
Is received and set in the counter 70 (S502 and S504 in FIG. 10). Thereafter, the computer B proceeds to S104 to S1 until the loop count value m becomes equal to the total number n of coordinate reading devices in S108.
By repeatedly executing step 10, a different counter value is transmitted to each coordinate reading device. On the other hand, each coordinate reading device executes steps S502 and S504, respectively, and sets different counter values to the counter 70. Then, the computer B determines that the loop count value m is equal to the total number n of the coordinate reading devices (S108: Y
es), a count start signal for instructing the start of counting is transmitted to each of the coordinate reading devices A1 to An (S11).
2). On the other hand, when each of the coordinate reading devices A1 to An receives the count start signal (S506: Yes), the counter 7 reads the counter 7.
The counting by 0 is started (S508). Note that the counter value C and the loop count value are stored in buffers provided in the computer B, respectively.

(Data Transmission / Reception) Next, the flow of data transmission / reception performed between the coordinate reading devices A1 to An and the computer B will be described with reference to FIGS. When the count value C of the counter 70 reaches a preset count value C1 (predetermined timing according to claim 1), the coordinate reading apparatus (S702 in FIG. 11: Ye)
s) If the transmission data is stored in the transmission buffer (not shown) (S704: Yes), the transmission data is transmitted to the computer B (S706). For example,
Assuming that the initial value set in the counter 70 is “65536”, the transmission data is transmitted when the count value of the counter 70 becomes “0”. Here, since the initial value set in the counter 70 in each of the coordinate reading devices A1 to An is different among the coordinate reading devices, the timing at which each of the coordinate reading devices A1 to An transmits data is different. Therefore, each coordinate reading device A1
There is no possibility that data transmitted from An will collide on the data transmission line.

On the other hand, the computer B receives the data packet transmitted from the coordinate reading device and accumulates it in a reception buffer (not shown) (S202 in FIG. 8), and stores the data packet in the data packet footer (FIG. 5A). The error code included is checked (S204). If the received data packet is correct data (S206: Yes), data processing such as storing the received data packet in the HDD 90 is performed (S208). Here, each coordinate reading device A1
To An transmit data packets A1 to An at different timings, respectively.
Are the data packets A1 to
An can be received respectively. Therefore, there is no possibility that the data packets A1 to An transmitted from the coordinate reading devices A1 to An will be confused in the computer B.

[Second Embodiment] Next, a second embodiment of the position coordinate data communication system according to the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 12 is a flowchart showing the flow of the counter control executed by the computer B.
Since the flow is the same as that of the first embodiment except for the flow of the counter control executed by the computer B, the flow of the counter control will be mainly described here, and the description of the same parts will be omitted. The computer B sets the counter value C to an initial value, and sets the loop count value m to an initial value “1” (S120). Subsequently, the computer B transmits an initial value as a counter value to the first coordinate reading device A1 (S1).
22), reset the timer 89 (FIG. 4) (S12)
4). Subsequently, the computer B increments the loop count value m by "1" (S126), and if the loop count value m is not equal to the total number n of coordinate reading devices (S1).
28: No), the timer 89 is started (S130),
It waits until the counted value t of the timer 89 becomes equal to or longer than the preset data packet transmission time tp (S13).
2).

When the time value t of the timer 89 reaches the data packet transmission time tp (S1), the computer B
32: Yes) to the second coordinate reading device A2 S120
The initial value set in is transmitted (S122). Thereafter, the computer B determines in step S128 that the loop count value m
S122 to S132 until it is determined that is equal to the total number n.
Is repeatedly executed, and the counter C set in S120 in each coordinate reading device at every data packet transmission time tp interval.
Send the initial value of. As described above, if the position coordinate data communication system of the second embodiment is used, even if the initial value set in the counter 70 provided in each of the coordinate reading devices A1 to An is the same value, the initial value is stored in the data. Each coordinate reading device A1 is spaced at intervals of the packet transmission time tp.
An each of the coordinate reading devices A1 to A
There is no risk that data packets will be transmitted at the same timing from n, and there is no risk that data packets will collide with each other on the data transmission line. Therefore, there is no possibility that the data packet transmitted from each of the coordinate reading devices A1 to An will be confused in the computer B.

Third Embodiment Next, a third embodiment of the position coordinate data communication system according to the present invention will be described with reference to FIG.
3 will be described. Even if the initial values of the counters set in the coordinate reading devices A1 to An are different from each other, the data transmission timings may be the same if the data packets have different lengths. The position coordinate data communication system according to the embodiment is characterized in that even if data is transmitted from each coordinate reading device at the same timing, no confusion of data occurs in the computer B. FIG. 13 is a flowchart illustrating a flow of a data transmission process performed by the coordinate reading device. Since the flow is the same as that of the first embodiment except for the flow of the data transmission process executed by the coordinate reading device, the flow of the data transmission process will be mainly described here, and the description of the same parts will be omitted.

When the coordinate reading device determines that the transmission data is stored in the transmission buffer (S710: Yes) and the data transmission line is not in use (S712: No), the coordinate reading device reads the transmission data stored in the transmission buffer. Send (S
714). Subsequently, the coordinate reader monitors the data transmission line (S716), and the monitored data is
If the transmitted data is not the same as the transmitted data in 714 (S718: No), the counter 7 is in the state of transmitting data at the same timing, so that the counter 7
The counting by 0 is started (S720), and the process waits until the count value C reaches a preset count value C1 (S722). Here, if the coordinate reading devices A1 and A2 transmit data at the same timing,
The coordinate reading devices A1 and A2 simultaneously start counting by their own counters 70, respectively. However, since different initial values are set in the counters 70 of the two coordinate reading devices by the computer B, the data transmission timings are different. Therefore, in the next transmission, the data transmitted from both coordinate reading devices does not collide with each other in the data transmission line. If a data collision occurs,
The computer B considers the data invalid by referring to the error code included in the footer of the received data packet.

In the coordinate reading apparatus, when the count value C is C
When the number reaches 1 (S722: Yes), retransmission of transmission data is attempted (S710 to S718), and when the monitored data is the same as the data transmitted by itself (S718: Yes).
s), and wait until the next transmission data is accumulated in the transmission buffer (S710). As described above, if the position coordinate data communication system of the third embodiment is used, even when data packets are transmitted at the same timing, when retransmitting, data is transmitted to the computer B without collision. Since the data can be transmitted, there is no possibility that data is confused in the computer B.

[Other Embodiments] As shown in FIG. 5B for explaining another configuration of a data packet, a variable D1 that increases or decreases every time a data packet D1 is transmitted.
g can be attached to the data packet D1. According to this configuration, even when a plurality of data packets are transmitted from the same coordinate reading device to the computer B,
Since the variables of each data packet are different, data packets of the same identification code can be stored in the order of the values of the variables as shown in FIG. The processing in each coordinate reading device and the processing in the computer B are as follows.
The present invention is not limited to the combinations described in the above embodiments, and the processes described in the embodiments can be freely combined. Further, in each of the above embodiments, the case where the position coordinate data communication system according to the present invention is used in a school class has been described as an example. However, the present invention is also applicable to a case where a meeting such as a company or an individual is held in a group. Of course. Furthermore, in each of the above embodiments, a LAN is used as the communication means, but wireless communication may be used. Alternatively, a configuration may be employed in which a coordinate reading device is connected to the computer B and a computer is connected to each coordinate reading device, so that positional coordinate data is transmitted and received from both.

[Correspondence between Claims and Embodiments] By the way, the pen 60 corresponds to the coordinate input means according to claim 1, the writing surface 21a corresponds to the coordinate input surface, and the computer B corresponds to the information processing device. Corresponding. Further, the counter 70 corresponds to the measuring means according to claim 2, and the data transmission lines L1 to L
n corresponds to the communication means according to claim 5. Further, S702 to S706 in FIG. 11 executed by the coordinate reading device or S710 to S722 in FIG. 13 function as the transmission unit according to claim 1, and the computer B executes the processing in FIG.
102 to S110, or S120 to S13 in FIG.
2 functions as control means.

[Brief description of the drawings]

FIG. 1A is a perspective view of a coordinate reading device according to a first embodiment, and FIG. 1B is an explanatory diagram of the coordinate reading device shown in FIG. is there.

FIG. 2 is an explanatory diagram showing a configuration of a network when data communication is performed between a plurality of coordinate reading apparatuses and a computer B;

FIG. 3 is an explanatory diagram showing a main electrical configuration of the coordinate reading device.

FIG. 4 is an explanatory diagram showing a main electrical configuration of a computer B.

FIG. 5A is an explanatory diagram showing a main configuration of a data packet, FIG. 5B is an explanatory diagram showing another configuration of a data packet, and FIG. FIG. 4 is an explanatory diagram showing a configuration of a stored data packet.

FIG. 6 is a flowchart showing a main processing flow of a computer B;

FIG. 7 is a flowchart illustrating a flow of counter control executed by a computer B in S100 of FIG. 6;

FIG. 8 is a flowchart illustrating a flow of a data receiving process executed by a computer B in S200 of FIG. 6;

FIG. 9 is a flowchart showing a main processing flow of the coordinate reading apparatus.

FIG. 10 is a flowchart showing a flow of an initial value receiving process executed by the coordinate reading device in S500 of FIG. 9;

FIG. 11 is a flowchart illustrating a flow of a data transmission process executed by the coordinate reading device in S700 of FIG. 9;

FIG. 12 is a flowchart illustrating a flow of counter control executed by a computer B in the second embodiment.

FIG. 13 is a flowchart illustrating a flow of a data transmission process executed by the coordinate reading device according to the third embodiment.

[Explanation of symbols]

 10 writing panel 21a writing surface (coordinate input surface) 60 pen (coordinate input means) 70 counter (measuring means) A1 to An coordinate reading device B computer (information processing device) L1 to Ln data transmission line (communication means)

Claims (8)

[Claims] 1. A coordinate reading device for reading the position coordinates of the coordinate input means on the coordinate input surface using magnetic coupling generated between the coordinate input means and the coordinate input surface, and a plurality of the coordinate reading devices. An information processing device capable of communicating with the information processing device; and the coordinate reading device includes a transmitting unit configured to transmit position coordinate data indicating the read position coordinates to the information processing device at a predetermined timing. The position coordinate data communication system, further comprising: control means for controlling the coordinate reading device such that the predetermined timing differs for each of the coordinate reading devices. 2. The coordinate reading device includes a measuring unit that measures a time until the predetermined timing is reached, and the control unit determines the time set for each of the coordinate reading devices. 2. The position coordinate data communication system according to claim 1, wherein the position coordinate data communication system can be set differently. 3. The difference between the predetermined timing set in the first coordinate reading device and the predetermined timing set in the second coordinate reading device is at least transmitting the position coordinate data. 3. The position coordinate data communication system according to claim 1, wherein the time is longer than a time required for the position coordinate data communication. 4. The apparatus according to claim 1, wherein the transmitting unit transmits data that changes each time the position coordinate data is transmitted to the information processing device together with the position coordinate data. 1
4. A position coordinate data communication system according to any one of the above. 5. The transmitting means monitors position coordinate data communicated by communication means for connecting the coordinate reading device and the information processing device when transmitting the position coordinate data, and monitors the monitored position coordinate data. The method according to any one of claims 1 to 4, wherein when the position coordinate data is different from the position coordinate data transmitted by itself, transmission of the position coordinate data is waited until the predetermined timing comes. The position coordinate data communication system according to the above. 6. The position coordinate data communication system according to claim 1, wherein the transmitting unit transmits the position coordinate data to the information processing device by packet communication. . 7. The information processing apparatus according to claim 1, wherein the transmitting unit transmits the position coordinate data to the information processing device together with identification data for identifying the coordinate reading devices. A position coordinate data communication system according to one of the preceding claims. 8. The information processing apparatus according to claim 1, wherein the transmitting unit transmits the position coordinate data to the information processing device together with data indicating when the position coordinate data was transmitted. A position coordinate data communication system according to one of the preceding claims.