JPH04169923A - Communication system for coordinate input device - Google Patents

Abstract

PURPOSE:To distribute a general serial interface to another peripheral device without using the serial interface by transferring absolute coordinate data and relative coordinate data to a host computer through a bus-mouse interface by selection or switching. CONSTITUTION:A transmission part 9 is provided with a pulse circuit 11 which outputs a two-phase pulse train in a prescribed transfer period in accordance with the integer indicated by binary 8-bit string constituting data to the transferred. A reception part 10 is provided with a resettable counting circuit 12 which counts pulse edges included in the two-phase pulse train and a reading circuit 13 which successively reads and resets the counted value of the counting circuit 12 and totalizes the counted value to settle the number of received pulse edges at the time when the read counted value is 0. Consequently, absolute coordinate data and relative coordinate data are switched by a desire, and selected coordinate data is transferred by a common hardware constitution. Thus, absolute coordinate data is transferred to the bus-mouse interface.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a coordinate input device that transfers binary data representing absolute coordinates and biphasic phase pulses representing relative movement amounts to a bus mouse port that can only input relative movement amounts. And binary-
Concerning the processing of a host computer that receives data.

[Conventional technology]

Computer coordinate input devices include digitizers that handle absolute coordinates and mice that handle relative movement amounts. As an interface between these coordinate input devices and a computer, a serial interface is generally used in the case of a digitizer, and a bus mouse interface is used in the case of a mouse.

First, we will explain the serial interface used in digitizers that handle absolute coordinates.

Generally, a serial interface converts bit parallel data into bit serial data and transfers the data from a receiving section to a transmitting section. For relatively low-speed serial interfaces such as digitizers, an asynchronous start-stop synchronization method is often used.

This method will be explained by taking the case of transferring absolute coordinate data from a digitizer to a host computer. FIG. 13 is a perspective view showing an outline of the communication system between the digitizer and the host computer.

Digitizer 1 is a tablet that defines a two-dimensional seating surface.
It is composed of a z-plane sensor section 2. When a desired position on the surface of the tablet flat sensor section 2 is designated using a suitable input device, such as a stylus pen 3, the sensor section 2 generates an analog detection signal corresponding to the designated position. The digitizer I further includes an arithmetic processing circuit, and calculates data representing two-dimensional coordinate values of a specified position based on the analog detection signal. The calculated data is sent to the host computer 5 via the signal cable 4. The host computer 5 has a plurality of built-in interfaces for connection with peripheral input/output terminal devices, which can be used depending on the format of signals to be sent and received.

FIG. 14 shows the waveform of the output signal transmitted from the digitizer. Absolute coordinate data created by a digitizer, for example 8-bit parallel data, is converted from parallel to serial and output as an 8-bit serial data signal as shown in FIG. For example, the 8-bit parallel data (10110101) is 1-0-1-1-0-1-0
-1 8-bit serial data signal. In such a dot data transmission method, the host computer usually has a built-in serial interface based on the R5-232C standard in order to accept data signals according to the asynchronous start-stop synchronization method. Therefore, peripheral end devices such as digitizers were generally connected to the host computer through an R5-232C interface.

Next, a bus mouse interface that accepts the amount of relative movement will be explained. A bus mouse is widely used as a coordinate input terminal device for computers, but it can only handle relative movement amounts. In addition, the bus mouse itself is larger in size than a stylus pen used as an input device for a digitizer, making it difficult to input characters and select menus.

On the other hand, digitizers can handle absolute coordinates and input characters easily. However, because the bus mouse is cheap and provides a simple interface, modern computers are equipped with a bus mouse interface as standard equipment. FIG. 15 shows a schematic structure of a bass mouse. A bus mouse is used to input the amount of movement into the host computer by moving its main body. Therefore, a rotatable ball 6 is attached to the bottom so that the main body can be moved. A pair of sensors 7 and 8 are in contact with the ball 6 to separately detect the amount of movement in the X-axis direction and the Y-axis direction.

FIG. 16 is an explanatory diagram of the operation of the bus mouse sensor.

The rotation axis of the X-axis sensor 7 is in contact with the ball 6 . Although not shown, the rotation axis of the Y-axis sensor 8 is also in contact with the ball 6 so as to be orthogonal to the rotation axis of the X-axis sensor 7. When the ball 6 rotates due to the movement of the bus mouse, the rotation axis of the X-axis sensor 7 rotates according to the amount of movement in the X-axis direction, and outputs the signal XA.
And discard XB. At the same time, switching signals S1 and S2 indicating switch inputs of the bus mouse are also output from the bus mouse.

FIG. 17 is an output signal waveform diagram of the bus mouse.

As shown in the figure, the output signal consists of a two-phase pulse train.

When the bus mouse moves in the positive direction of the X-axis, the pulse train
A is delayed in phase with respect to the pulse train XB. In this way, the number of pulse edges included in the output signal per unit time indicates the amount of relative movement of the bass mouse per unit time, and the phase state of the output signal indicates the direction of movement of the bass mouse.

Typically, the host computer has a built-in bus mouse interface to accept output signals and switching signals from the bus mouse. The bus mouse interface uses two 8-bit counters corresponding to the X and Y coordinates.
It measures the number of pulse edges in the output signal. This calculation result is read from an 8-bit counter every fixed period (for example, 8 as) by the mouse timer of the host computer, and the relative movement amount of the bus mouse and the switch input during the fixed period are detected. The host computer uses the relative movement amount sent from the bus mouse to set the absolute coordinates (for example, 840
x 400 dots) and pass the absolute coordinates to the cursor display on the display or to the application program.

[Problems to be solved by the invention]

A serial interface board (such as RS-232C) built into a host computer has extremely high versatility, and there is a limit to the number of ports that can be used to connect various peripheral terminal devices that employ an asynchronous start-stop synchronization method.

Therefore, there has been a need for a communication system that allows data transfer using an interface other than the serial interface built into the host computer. For example, it is a bus mouse port for connecting a bus mouse.

By the way, as shown in FIG. 14, the output signal of the conventional digitizer consists of a binary bit string according to the asynchronous start-stop synchronization method. On the other hand, as shown in FIG. 17, the output signal from the bus mouse consists of a two-phase pulse train. Therefore, the output signal formats of conventional digitizers and bus mice are different from each other, and the absolute coordinate data of the digitizer cannot be directly input to the bus mouse interface of the host computer.

As can be understood from the above explanation, data consisting of a binary bit string cannot be input to the host computer's bus mouse interface using the asynchronous start-stop synchronization method, but the bus mouse interface is more versatile than the serial interface. Therefore, there is an increasing demand in the market to use the bus mouse interface to transfer not only relative movement information of a coordinate indicator but also absolute coordinate information. However, conventional bus mouse interfaces have not been able to meet both of these demands.

[Means to solve the problem]

In view of the above-mentioned problems with the conventional data communication method, the first object of the present invention is to provide a method for transferring absolute coordinate data from a coordinate input device such as a digitizer to a bus mouse interface included in a host computer or the like. .

By the way, in actual use of a digitizer, there are many cases where it is desired to transfer not only absolute coordinates but also relative coordinate data or relative movement data to a host computer or the like as desired. Therefore, the present invention provides a new transfer method that can select either absolute coordinate data or relative coordinate data as appropriate and transfer it to a bus mouse interface built in a host computer or the like via common hardware. The second purpose is to do something.

First, a method for transferring absolute coordinate data using a bus mouse port will be explained with reference to FIG. FIG. 1 is a block diagram showing the overall configuration of a communication system according to the present invention. This communication system is composed of a coordinate data transmitter 9 and a coordinate data receiver 10.

The transmitter 9 has a pulse circuit 11 that outputs a two-phase pulse train including a corresponding number of pulse edges within a predetermined transfer period according to the integer represented by the 8 binary bit string constituting the data to be transferred.

On the other hand, the receiving unit IO includes a resettable counting circuit 12 that counts pulse edges included in a two-phase pulse train, and reads and resets the counts of the counting circuit 12 sequentially at predetermined reading intervals within the transfer period. The reading circuit 13 includes a reading circuit 13 which adds up the counted values when the number becomes zero and determines the number of accepted pulse edges. In other words, the counting circuit 12 of the pulse data receiving section IO
and the reading circuit 13 constitute a so-called bus mouse interface.

Preferably, the CPU of the transmitting unit 9 includes a code circuit 14 that attaches positive and negative signs to the transfer data in order to mutually identify a plurality of series of absolute coordinate data, and the pulse circuit 11 provides two-phase control according to each code. The phase of the pulse train can be selected. In addition, the pulse data receiving section 1 (l) is designed to mutually identify a series of data transferred in chronological order according to the phase.

The code circuit I4 is configured to, for example, alternately assign positive and negative codes to a series of data, thereby identifying preceding and succeeding data. Alternatively, the code circuit 14 assigns a different code to the first data in a series of data, so that the reception side can detect the start point of transmission of the series of data. Preferably, the pulse circuit It consists of a pair of X
It consists of a pulse circuit and a Y pulse circuit, and is capable of transmitting a pair of data simultaneously. Correspondingly, on the receiving side, the counting circuit 12 is composed of a pair of X counting circuit and Y counting circuit, and can receive a pair of data simultaneously.

The pair of X and Y pulse circuits can transmit one pair of data during the first half of the transfer period, and the other pair of data during the second half of the transfer period. Send data. Such a communication method enables the operation of a digitizer that transmits absolute coordinate data to the bus mouse port.

By using the circuit or hardware of the transmitter 9 that implements this communication method, it is possible to easily transmit a two-phase pulse representing the amount of relative movement. In other words, by using the °2 invitation pulse generation circuit II, the CPU calculates the relative movement amount based on the absolute coordinate data obtained from the digitizer that inputs the absolute coordinates, and generates the two-phase phase pulse from this pulse circuit. It is possible to move coordinate indicators such as stylus pens and cursors relative to each other like a mouse.

That is, in the communication system according to the present invention, absolute coordinate data and relative coordinate data can be switched as desired, and the selected coordinate data can be transferred using a common hardware configuration.

In addition, when transferring relative coordinate data, the code circuit 14 of the transmitter 9 assigns a positive or negative code depending on the direction of relative movement. The phase of the biphasic pulse to be sent out is determined according to this sign. The reading circuit 13 of the receiver IO detects this phase and obtains relative movement direction information. Further, in parallel with the transfer of the relative coordinate data, an output port 29 is added to the transmitter 9 to transfer the switching signals S1 and S2, and a corresponding input port 26 is provided to the receiver 10. There is. This switching signal is used to open/close a window, execute various program processes, read instructions on a display, etc. The operation of the communication method will be explained using the transfer of four coordinate data as an example. The data is output by the transmitter in the form of a two-phase pulse train. On the other hand, a bus mouse interface built into a receiving section of a host computer or the like has the following functions.

1. Function to measure the number of pulse edges included in a two-phase pulse train.

2. A function that detects whether the phase of a two-phase pulse train is leading or lagging and distinguishes whether the data is positive or negative.

3. A function that can simultaneously count the number of pulse edges in a pair of two-phase pulse trains.

4. A function that resets the count value when it is read.

The four functions described above are executed by dedicated hardware (mouse counter) built into the receiver. As an example of the receiving section, the received two-phase pulse train is converted from -128 to +
127 to an 8-bit two's complement representation.

The transmitter uses the above four functions of the receiver to transmit coordinate data in the form of a two-phase pulse train to the receiver.

First, transfer of absolute coordinate data will be explained.

If one piece of data consists of seven binary bit strings, the integer 0 to 1 represented by the binary bit string
A two-phase pulse train including 27 pulse edges is output. For example, as shown in Figure 2, if the absolute coordinate data is 18H, the binary bit string represents the integer 24, so 2
A two-phase pulse train including four pulse edges is output. The biphasic pulse train includes two phase components XA and XB.

The sign of the data determines the phase relationship between the two components. For example, if the sign of the data is positive, component
The component XA is 90 degrees ahead of the component B, and conversely, when the sign of the data is negative, the component XA is 90 degrees behind the component XB. Note that the pulse edges indicate the rising and falling points of the pulses included in the two-phase pulse train, and the number of pulse edges is obtained by counting all the pulse edges included in the two-phase pulse train. A counting circuit, that is, a mouse counter in the receiving section counts the pulse edges and sets them in a register as one piece of absolute coordinate data. The data I8H output by the transmitting section can be obtained by reading the mouse counter by the reading circuit of the receiving section, for example, the CPU. When the CPU reads the mouse counter, the mouse counter is cleared.

The mouse counter overflows if the CPU does not read the counted value even though the two-phase pulse train is being sent. For example, after the transmitter transmits the data FF,
If the receiving section transmits the next coordinate data 5 before reading the mouse counter, the value of the mouse counter will become 04. If the mouse counter overflows in this way, the data output from the transmitter will not be correctly transferred to the receiver. For this reason, it is necessary to adjust the two-phase pulse train output timing of the transmitting section and the mouse counter reading timing of the receiving section. In the communication system according to the present invention, overflow of the mouse counter is prevented by adopting the transfer system shown in FIG.

As shown in the data transfer timing chart in Fig. 3, the transmitter outputs two-phase pulse trains XA and XB containing the number of pulse edges corresponding to the integer represented by the data to be transmitted every predetermined transfer period (2, 5ss). do.

The receiving unit has a reading interval (1a) shorter than one transfer period.
s) Read the mouse counter every time.

That is, by sequentially reading and resetting the mouse counter during the output of the two-phase pulse train, overflow of the mouse counter is prevented, and the state in which the output of the two-phase pulse train is stopped can be recognized, and data sent sequentially is separated. , the timing chart in Figure 3 is an example of integer 4.
It shows the operation of sequentially transferring two pieces of data corresponding to 0 and the integer 35. When the transmitting section starts outputting a two-phase pulse train including 40 pulse edges in order to transfer the first data, the CPU of the receiving section reads the mouse counter at timing (3). At this time, the CPU reads the count value of the already output pulse edge, for example, 15. At this time, the mouse counter is reset, but the pulse edge count is #! I can continue. At the next reading timing ■, the remaining countability 25 is read. The receiving section adds up and holds the countability obtained by the two readings, and determines the number of accepted pulse edges. At the following timing (2), the CPU of the transmitter also reads the mouse counter, but the output of the pulse train has already ended and the mouse counter has been reset at the previous reading timing (2), so the reading result is O. By reading the count value 0 from the mouse counter, the receiving section reads 1 from the transmitting section.
It is recognized that the data transfer has been completed, and that the total count value 15+25-40 is an integer representation of the transferred data. Subsequently, in the second transfer period, a pulse train including the number of pulse edges corresponding to the integer 35 represented by the second data to be transmitted is output. At this time, the receiving section sequentially reads the mouse counter at reading timings (1), (2), and (2), and similarly measures and determines the number of transmitted pulse edges.

Next, a method for transmitting four pieces of data in one transfer process using the continuous transfer method of absolute coordinate data explained in FIG. 3 will be described. In this method, two pieces of data can be transferred simultaneously using a pair of X and Y counters that constitute a mouse counter. By transferring one pair of data within the first half transfer period and transferring another pair of data during the second half transfer period, a total of four data transfers are completed in one transfer process.

Since four pieces of data are transferred by the same transfer process, the receiving section must recognize each piece of data separately.

That is, it is necessary to identify whether the pair of data X and Y is sent during the first half transfer period or the second half of the four data. To perform this identification, a positive or negative sign is assigned to the data to be transferred.

That is, out of a pair of data X and Y that are transferred at the same time, data X is given a sign that is inverted each time it is transmitted.

This assignment of positive and negative signs is performed by selecting the phase of the corresponding two-phase pulse train. As a result, the receiving section detects the selected phase and determines whether the received data is positive or negative. Then, if data
Each piece of data can be identified.

In order to carry out the above identification, data X must be given a negative sign at least once in one transfer process. If the data is 0 at the timing of outputting negative data, the receiving section cannot identify whether it is the first half data or the second half data. Therefore, if the data to be given a negative sign is 0, the transmitter tentatively assigns a numerical value of -128 to the data, and the receiver recognizes that the data is actually 0.

Furthermore, in order to improve the reliability of data separation and reading in the receiving section, the transfer method shown in FIG. 4 is also possible. That is, the transmitter assigns a positive sign to data X and a negative sign to data Y for a pair of data sent in the first half transfer period among the four pieces of data. Also, of the pair of data sent in the latter transfer period, data X is given a negative sign and data Y is given a positive sign. Then, if the data X received in the first half is positive and data Y is negative, and the data X in the second half is negative and data Y is positive, the receiving unit recognizes that the four received data are normal. Any other combination of codes is considered an error. This makes it possible to constantly check the transferred data. The communication method described above enables accurate communication of four pieces of data through one transfer process.

The communication method according to the present invention is not limited to the case where four pieces of data are transferred in one transfer process, but for example, eight pieces of data are transferred in one transfer process as shown in Table 1 below. I can do things.

Table 1 Data x +0-0+0-0+0 Data y -o+o+o+o-.

In this example as well, a pair of pulse circuits X and Y are used to transfer each pair of data X and Y.

The sign of data X is inverted every time it is transferred, so that pairs of data before and after it can be identified from each other. Also, a negative sign is attached to the data Y that is output first in one transfer process, and a positive sign is attached to the remaining data Y. If the received data Y has a negative sign, the receiving unit recognizes that the received data is the first data in one transfer process. In this way, the transmitting section and the receiving section can transfer a large amount of data while being synchronized with each other. In addition, 1
Checksum or C of the final data in the transfer process
It is possible to know the reliability of data transferred by RC.

Next, based on FIG. 5, a means for transmitting the relative movement amount of the coordinate indicator from the digitizer to the host computer via the above-mentioned node \-ware using two-phase pulses, which have the original meaning of a bus mouse, is described. explain. In this example, a pair of relative coordinate data X and Y is sent from the transmitter every predetermined transfer period, e.g., l(1++s), and the receiver sends a pair of relative coordinate data
A pair of data X and Y is read each time. By setting the communication timing in this way, reception errors (mouse counter overflow) are prevented.

By the way, the two-phase pulse of the actual bus mouse is the 17th pulse.
As shown in the figure, when generating a biphasic pulse for a bass mouse, the pulse width is determined by the rotational speed of a sensor connected to the rotating shaft as shown in FIG. For this reason, the pulse width changes according to the moving speed of the bass mouse body, and the pulse will not be interrupted as long as the bass mouse is moving. However, in the present invention, the mouse counter of the receiver host computer is capable of reading the C.
Since the pulse change until the PU or mouse counter count value is read is only added or subtracted, it does not need to be the same pulse as the bus mouse. Therefore, when transmitting the amount of relative movement using the biphasic phase pulse generating circuit of the transmitter according to the present invention, biphasic phase pulses are intermittently transmitted every 10 m5 as shown in FIG. If the read timing of the host computer is set to 8■S, the mouse counter will not overflow. With such timing, the amount of relative movement can be transferred from a coordinate input device such as a digitizer to the host computer.

〔Example〕

Hereinafter, a preferred embodiment of the coordinate data communication system according to the present invention will be described in detail with reference to FIGS. 6 to 12. FIG. 6 is a diagram showing the hardware configuration built into the transmitter.

This hardware consists of a pair of X pulse circuits I5 and Y pulse circuits 16 that correspond to a pair of X mouse counters and Y mouse counters built into the receiving section, and a timing generation circuit 17 that defines the sending timing of the pulse train. ing. The X pulse circuit 15 and the Y pulse circuit IB have the same configuration and output an X pulse train (XA, XB) and a Y pulse train (YA, YB), respectively.

As shown in the figure, the X pulse circuit 15 is a pulse generator that generates a pulse train corresponding to the numerical value based on the 8-bit coordinate data and 1-bit code data sent from the 16-bit data bus DB connected to the digitizer's CPU. It consists of a circuit 18 and a phase circuit 19 that generates two-phase pulse trains XA and XB based on the pulse train. The pulse train generation circuit 18 includes a 9-bit latch circuit 20 for sequentially fetching data from the data bus, and an 8-bit binary clock signal CK for measuring the clock signal CK according to the binary representation value of the lower 8-bit data handled by the 9-bit latch circuit 20. It has a counter 21. The pulse train counted by a predetermined number is sent to the phase circuit 19 via the NAND circuit 28. The phase circuit 19 has a pair of D flip-flop circuits 22 and 23, and the lower 8 bit data handled by the 9-bit latch circuit 20 is advanced or delayed depending on the sign T2 indicated by the upper 1 bit. Outputs two-phase pulse trains XA and XB.

FIG. 7 is a timing chart for explaining the operation of the circuit shown in FIG. 6. In this embodiment, the clock CK that specifies the pulse edge arrangement interval of the two-phase pulse train is 2.
Let it be μs. Therefore, the period of the pair of pulse train components XA and XB of the two-phase pulse train is 8 μs. The output timing of the two-phase pulse train is determined by the signal T1. Signal T1 defines the output timing of four pieces of data that are output for one transfer process, and T1 is used when transmitting absolute coordinate data.
= 2.5ms. In this case, the transfer rate is 1
Transfer processing is performed 200 times per second. Furthermore, when transmitting relative coordinate data, T 1 = 1Oss is set. This switching is controlled by the CPU of the transmitter.

The C of the transmitting section is determined by the falling timing of the signal T1.
Interrupts the PU (INT), which causes the CPU to
The bit latch circuit 20 contains 8-bit data indicating the pulse output time and a 1-bit sign bit (T2) indicating whether the pulse is leading or lagging.
). When transmitting absolute coordinate data, the level of signal T2 becomes L when the data is in the first half, and becomes H when the data is in the second half. Furthermore, when transmitting relative coordinate data, the level of the signal T2 is set depending on whether the direction of relative movement is positive or negative. The lower 8 bits of the latched 9-bit data are loaded into the 8-bit binary counter 21. At timing (3) when the timing signal T1 becomes level H, the counter 21 starts counting the clocks CK, and counts the number of clocks corresponding to the integer value set in the counter 21. Then, the signal CY is raised at the timing (3) when the counting ends. 8-bit binary counter 2
1, outputs a clock signal CK that operates the phase circuit 19 at timing ■, and generates an X two-phase pulse train (X
A, XB). The Y pulse circuit 16 has the same configuration as the X pulse circuit 15, but when transmitting absolute coordinate data, the Y two-phase pulse train (YA, YB) is transmitted using the upper 1 bit (T2) indicating the sign of the 9-bit latch data.
The phase of is inverted with respect to the X two-phase pulse train.

In the configuration of the transmitting section shown in FIG. 6, the pulse train generation circuit 18 is configured by hardware consisting of a plurality of parts. However, the present invention is not limited to this, and it is also possible to configure the counter that generates the pulse train with a one-chip CPU that has a built-in CPU. FIG. 8 is a timing chart for explaining the operation of the pulse train generating means in such a case. As shown,
The pulse train generating means includes a one-shot counter and outputs a one-shot signal for a predetermined period of time in accordance with the value of the coordinate data to be transmitted. During this time, a 2 μs clock signal CK passes through the gate and is sent to the phase circuit. The phase circuit outputs two-phase pulse signals XA and XB having the number of pulse edges corresponding to the number of input clock signals. This configuration simplifies the circuit configuration of the transmitter.

Figure 9 shows the X two-phase pulse train and Y phase pulse train synthesized in this way.
The waveform of a two-phase pulse train is shown. In the waveform of Fig. 9, the integer value represented by the X data is 13, and the integer value represented by the Y data is -7.
An example is shown below.

Next, the hardware configuration of the receiving section is shown in FIG.

A receiving section consisting of a host computer or the like includes a mouse interface. The mouse interface includes a mouse counter 25 and a port 26. The mouse counter 25 includes an X counter for counting the X two-phase pulse train (XA, XB) and a Y counter for counting the Y two-phase pulse train (YA, YB). Port 26 is for receiving switching signals S1 and S2 sent from the mouse. The host computer constituting the receiving section further includes a CPU 27 and reads the count counted by the mouse counter 25.

FIG. 1 is a flowchart showing the absolute coordinate reading process performed by the host computer of the receiving section. In this embodiment, an example will be shown in which four pieces of data are divided into the first half and the second half and transferred in one transfer process. Out of the four data, select the first two data or the latter two data, but if the first two data are selected,
The CPU 27 reads the X counter, and if the X data is positive, performs addition processing until the count of the X counter becomes 0.

Next, the data of the X counter is read, and if the data is negative, addition processing is performed until the count of the X counter reaches O. If positive, jump to error processing. When the counts of the X counter and the X counter reach 0, it is determined that the transfer of the first half data from the transmitter has been completed, and the process moves on to receiving the second half data.

When the latter two data are selected, the X counter is read and if the X data is negative, addition processing is performed until the count of the X counter becomes 0.

If the X data is positive, jump to error processing. Next, the count of the X counter is read, and if the Y data is positive, addition processing is performed until the count of the X counter becomes 0. If it is negative, jump to error processing. X counter and X
When the count of the counter reaches 0, it is determined that the transfer of the second half of the data from the transmitting section has been completed, and the four transferred data are determined. The reading process then shifts to the receiving process of the first half data.

, Next, the transfer rate of the communication method according to the present invention is 1
An example will be explained in which four pieces of absolute coordinate data are communicated for each transfer process. The transfer rate is determined by the pulse train output timing time of the transmitting section and the mouse counter reading timing time of the receiving section. As an example of the receiving section, if the interval timer time is 21113, then 1
The transfer time for 4 pieces of data in one process is 5
2 = IOIIls, the transfer rate is 10 per second
There will be 0 transfers. The shorter the pulse train output timing of the transmitting section and the reading timing of the receiving section, the faster the transfer rate becomes, so by making both timings variable, any transfer rate can be achieved. The relationship between the interval timer and transfer rate is shown in Table 2 below.

Table 2 Next, an example of the absolute coordinate data format transferred by the data transfer method according to the present invention is shown.

Here, the transfer of digital data indicating absolute coordinate positions input by a digitizer to a host computer will be described.

Digital data consists of two or more bytes of bits and bytes depending on the size of the digitizer. - For example, in Table 3,
The bit and byte configuration of digital data is shown consisting of first to fourth bytes each consisting of 8 bits.

Table 3 Numbers 1 to 4 on the left side of Table 3 mean the first to fourth hides, and numbers 7 to O on the upper side indicate the 8-bit array in each byte. However, in this example, the most significant bit of each byte is empty. Therefore, information regarding one coordinate position is expressed by a 4x7-28 bit array. These 28-bit arrays are divided into first to fourth bytes. Here bit XO or
IO represents the X coordinate and can specify an X coordinate value of 0 to 2047, and bits YO to Y9 represent the Y coordinate and can similarly specify a Y coordinate value of 0 to 1023.

Further, bits SO to S5 represent switching signals related to the type of input device or gradation for one coordinate position. Bit RDY indicates that the coordinate indicator is within the effective area of the plane sensor section.

Finally, an embodiment of relative movement amount transfer according to the present invention will be described in detail with reference to FIG.

The two-phase pulse generation circuit shown in FIG. 6 can easily generate a two-phase pulse that exhibits a relative movement amount similar to that of a bass mouse using the algorithm shown in FIG. 12.

For absolute coordinate signals, the falling edge of signal T1 interrupts the CPU of the transmitter and writes data to the CPU or the two-phase phase pulse generation circuit, or for relative coordinates transmission, two-phase pulse generation is performed depending on the timing of the internal timer in the digitizer. Write data to the phase pulse generation circuit. 12th
As shown in the figure, first initialize the digitizer and bus mouse interface, and select the relative coordinate data communication mode of the digitizer program. Next, based on the results of the absolute coordinate calculation of the digitizer, relative movements ff1dX and dY are calculated at intervals of 10IIls and written into the two-phase pulse generation circuit. In this case, there is no need for a special procedure such as when communicating absolute coordinate data, and relative movement data in the range of +127 to -128 is simultaneously written into the X and Y two-phase pulse generation circuits. When the relative movement data is positive, the upper 1 bit of the 9-bit launch circuit 20 shown in FIG. 6 is set to L, and the lower 8 bits are set to relative movement amount values dX and dY. If the relative movement data is negative, the upper 1 bit of the 9-bit latch circuit 20 is set to H, and the lower 8 bits are set to the relative movement values dX and dY. For absolute coordinate data communication, switch SL of the bus mouse.

S2 is not used, or the coordinate indicator switch state is set to Sl in order to operate in the same way as a bus mouse.

Output as S2. If this two-phase phase pulse generation circuit is used, the CPU of the transmitter only sets the relative movement data at arbitrary time intervals, so it is extremely efficient.
PU can be utilized.

When the transfer interval is set to 10 ms, the transmitted data is read at every 5 IIs, which is shorter than the transfer interval.

〔Effect of the invention〕

The coordinate input device using the communication method according to the present invention can select or switch absolute coordinate data and relative coordinate data as desired and transfer them to the host computer via the bus mouse interface, so it can be transferred to the host computer via the bus mouse interface. There is no need to use a serial interface, and a general-purpose serial interface can be allocated to other peripheral devices.

This has the effect that a bus mouse interface dedicated to a bus mouse can be effectively used as an interface for a coordinate input device, and in addition, application programs that use existing bus mice can also be run.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of the coordinate data communication system according to the present invention, Fig. 2 is a waveform diagram of a two-phase pulse train, Fig. 3 is a transfer timing chart of absolute coordinate data, and Fig. 4 is a diagram of other absolute coordinate data. Transfer timing chart, FIG. 5 is a transfer timing chart of relative coordinate data, FIG. 6 is a circuit configuration diagram of the transmitter, FIG. 7 is an operation timing chart of the transmitter,
Fig. 8 is an operation timing chart of another example of the transmitter, Fig. 9 is a waveform diagram of an XY two-phase pulse train, Fig. 10 is a block diagram of the receiver, and Fig. 11 is a flowchart of the absolute coordinate data reading process of the receiver. , Fig. 12 is a flowchart of the relative movement amount data transmission process of the transmitter, Fig. 13 is a perspective view showing an overview of the conventional communication method, Fig. 14 is a transfer signal waveform diagram of the conventional transfer method, and Fig. 15 is the conventional transfer method. FIG. 16 is an explanatory diagram of the operation of the bass mouse sensor, and FIG. 17 is an output signal waveform diagram of the bass mouse.

Claims (1)

[Claims] 1. In a communication system for a coordinate input device that transfers coordinate data consisting of a binary bit string from a transmitter to a receiver, the transmitter transmits either absolute coordinate data or relative coordinate data obtained by the coordinate input device. A selection means for selecting one of the two to be transferred as desired, and a two-phase pulse train containing a corresponding number of pulse edges within a predetermined transfer period according to the integer represented by the binary bit string constituting the selected coordinate data to be transferred. The receiver has a resettable counting means for counting pulse edges included in the two-phase pulse train, and reads and resets the count of the counting means at a predetermined reading timing within the transfer period. 1. A communication method for a coordinate input device, characterized in that the coordinate input device has a reading means for executing and determining the number of accepted pulse edges. 2. It includes a code means for attaching a positive or negative sign to the absolute coordinate data in order to mutually identify a plurality of series of absolute coordinate data to be transferred, and the pulse means changes the phase of the two-phase pulse train according to the sign. Claim 1 characterized by comprising: a transmitter that selects the coordinate data; and a receiver that mutually identifies a series of absolute coordinate data transferred in time series according to the phase.
Communication method of the coordinate input device described in . 3. The communication system for a coordinate input device according to claim 2, wherein the code means alternately assigns positive and negative codes to the series of absolute coordinate data. 4. The communication system for a coordinate input device according to claim 2, wherein the code means assigns a different code to the first absolute coordinate data of the series of absolute coordinate data. 5. The transmitter has a pair of pulse means for simultaneously transmitting a pair of coordinate data, and the receiver has a pair of counting means for simultaneously receiving a pair of coordinate data. A communication system for a coordinate input device according to claim 1. 6. The pair of pulse means transmits one pair of coordinate data within the first half transfer period, and transmits the other pair of coordinate data within the second half transfer period, thereby transmitting four coordinates in one transfer process. 6. A communication system for a coordinate input device according to claim 5, characterized in that data is transmitted. 7. The reading means of the receiving section detects the selected relative coordinate data sent from the transmitting section every transfer period every reading period not larger than the transfer period. Communication method for coordinate input device. 8. The transmitter calculates relative coordinate data from the absolute coordinate data directly obtained by the coordinate input device, and the selected relative coordinate data is given a positive or negative sign by the sign means, and then the pulse means is used to calculate the relative coordinate data. 2. The communication system for a coordinate input device according to claim 1, wherein the communication system is transmitted as a relative movement two-phase pulse train similar to a bus mouse. 9. When reading the selected absolute coordinate data, the reading means of the receiving section sequentially reads and resets the count of the counting means at predetermined reading intervals within each transfer period, and resets the read count. 2. The communication system for a coordinate input device according to claim 1, wherein the number of accepted pulse edges is determined by summing the counts when the number of pulse edges becomes zero.