KR920002594B1 - Touch position detection circuit and method of touch screen - Google Patents

Abstract

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Description

Touch position detection circuit and method of touch screen

1 is a touch position detection circuit diagram of the present invention.

2a-i is a signal flow diagram showing an embodiment of the touch position detection method of the present invention.

3 is an explanatory diagram showing a memory map of touch position values according to the touch position detection method of the present invention.

4a and b are signal flow diagrams showing another embodiment of the touch position detection method of the present invention.

* Explanation of symbols for main parts of the drawings

1: Micom 2: X-axis detection voltage supply

3: Y-axis detection voltage supply unit 4: Touch screen

5: waveform shaping section 6-9: first to fourth detection voltage amplifier sections

10: analog / digital converter 11: control signal output unit

12: flip flop

The present invention relates to a touch position detection circuit and a method of a touch screen for detecting a touch position of a touch screen used for data input in a system using a computer.

Recently, with the development of computer technology, a touch screen has been developed to easily input data in place of a keyboard. In such a touch screen, when a user touches a finger or a tip of a ballpoint pen, the resistance values of the X-axis and the Y-axis are varied according to the contact position thereof.

The present invention has been made a touch position detection circuit and a method for detecting a touch position of the touch screen so that data can be simply input using the touch screen as described above in detail with reference to the accompanying drawings.

1 is a touch position detection circuit diagram of the present invention, as shown here, the microcomputer 1 for controlling the overall operation of the touch position detection and the microcomputer 1 is the X-axis and Y-axis control terminals (XH, XL) ( Inverters (I ₁ ) (I ₂ ) and resistors (R _1- R ₅ ) (R ₆ ) respectively supplying the X-axis and Y-axis detection voltages to the touch screen 4 according to the control signals output to YH and YL. X- and Y-axis detection voltage supply units (R) (3) consisting of -R ₁₀ , transistors TR ₁ , TR ₂ (TR ₃ , TR ₄ ) and variable resistors VR ₁ (VR ₂ ), Waveform shaping portion 5 comprising diodes D ₁ -D ₈ shaping the voltage output by touch screen 4 according to the touch position, and capacitor C amplifying the output voltage of the waveform shaping portion 5. ₁ ) (C ₂ ) (C ₃ ) (C ₄ ), resistors (R ₁₁ , R ₁₂ ) (R ₁₃ , R ₁₄ ) (R ₁₅ , R ₁₆ ) (R ₁₇ , R ₁₈ ) and operational amplifier (OP ₁ ) (OP ₂₎ (OP ₃₎ (OP ₄₎ first-fourth detection voltage amplifying unit 6, 7, 8, 9 and the microcomputer (1) the address bus (AB) in the in Address to output An analog / digital converter 10 which selects an output signal of the first to fourth detection voltage amplifiers 6-9 according to the signal, converts the output signal into a digital signal, and outputs the digital signal to the data bus DB; Start signal ST and output enable signal OE to the analog / digital converter 10 according to the input / output read signal SR, the analog / digital conversion address signal ADR, and the input / output write signal SW. Ora gates OR ₁ and OR ₂ for controlling the analog / digital converter 10 to convert the output signal of the selected first-fourth detection voltage amplifier 6-9 into a digital signal and output the same; Inverters I ₃ and I ₄ apply an interrupt signal INT to the microcomputer 1 according to the control signal output unit 11 and the conversion completion signal EOC of the analog / digital converter 12 to convert the digital signal. Consisting of a flip-flop (12) indicating that the conversion to Unexplained code CLK is a clock signal and Vcc is a power terminal.

In the touch position detecting circuit of the present invention having such a configuration, the microcomputer 1 has the X-axis control terminal XH (XL) while the operating power is applied to the power supply terminal Vcc, and the clock signal CLK is applied. When the low-potential detection control signal is outputted, the high potential of the control terminal XH is inverted to a low potential through the inverter I ₁ and then applied to the base side of the transistor TR ₁ so that it is turned on and the control terminal ( The high potential of the XL is applied to the base axis of the transistor TR ₂ so that it is turned on so that the operating power supply of the power supply terminal Vcc is the transistor TR ₁ , the variable resistor VR ₁ , the variable resistor VR ₁ , and the resistor. (R ₃ ), the X-axis of the touch screen 4 and the transistor TR ₂ flow.

In this state, when the user touches the finger or the tip of a ballpoint pen on the touch screen 4, the touch screen 4 varies the resistance value of the X-axis according to the touched position, and thus the detection voltage is changed. Is shaped through the waveform shaping section 5, and amplified through the first and second detection voltage amplifying sections 6 and 7 to the input terminals IN ₁ (IN ₂ ) of the analog / digital converter 10. Is entered.

The microcomputer 1 outputs an address signal through the address bus AB and applies it to the analog / digital converter 10, and also input / output read signal SR, analog / digital conversion address signal ADR, and input / output write signal. The control signal output unit 11 outputs the start signal ST and the output enable signal OE to the analog / digital converter 10 according to (SW), so that the analog / digital converter 10 touches the X-axis. The position detection voltage, that is, the output signals of the first and second detection voltage amplifiers 6 and 7 are sequentially converted into digital signals, output to the data bus DB, input to the microcomputer 1, and digitally. As the conversion of the signal is completed, the analog-to-digital converter 10 outputs the conversion completion signal EOC and applies it to the clock terminal CK of the flip-flop 12, so that the flip-flop 12 goes to the output terminal Q. Outputs a high potential, which is interrupted by the microcomputer (1) Applied by arc INT, the microcomputer 1 senses that the conversion to the digital signal is completed, inputs and stores the signal of the data bus DB, that is, the X-axis touch position data, and outputs the clear signal CL. The flip flop 12 is cleared.

When the data of the touch position of the X-axis touched by the touch screen 4 is detected in this way, the microcomputer 1 outputs a high potential to the Y-axis control terminal YH YL to supply the Y-axis detection voltage supply unit 3. Transistors TR ₃ and TR ₄ are turned on to supply the Y-axis detection voltage to the touch screen 4, and the Y-axis detection voltage that is varied according to the touch position of the touch screen 4 is the waveform shaping unit 5. And are amplified by the third and fourth detection voltage amplifiers 8 and 9, and then input to the analog / digital converter 10, under the control of the microcomputer 1 as in the X-axis detection voltage. After converting into a digital signal and input to the microcomputer 1, when the digital conversion and input of the Y-axis detection voltage is completed, the microcomputer 1 outputs a high potential clear signal CL to clear the flip-flop 12. Let's go.

2 is a signal flowchart showing an embodiment of the touch position detection method of the present invention. The touch position detection method of the present invention performs an initialization routine in step 100 as shown in FIG.

In the initialization routine, as shown in FIG. 2B, each register is evacuated in step 101, and in step 102, all X-axis and Y-axis touch position data stored in the memory map are cleared, and step 103 In step 104, the storage variable indicating that the touch position data is stored in the memory map is cleared, and in step 104, all external interrupts such as the interrupt signal INT are interrupted, and the clear signal CL is outputted and flipped. After the flop 12 is cleared, in step 105, the low potential is output to both the X-axis and Y-axis control terminals XH, XL, YH, and YL to cut off the power supply of the touch screen 4.

Then, in step 106, the vector of the timer interrupt is changed to the timer subroutine, and in step 107, the vector of the timertic interrupt is changed to the subroutine of the touch screen 4, and then in step 108, the timer interrupt is changed. In other words, the period of the user's touch on the touch screen 4 is very fast, so that the period of the timer interrupt can be quickly detected so that the touch of the touch screen 4 can be accurately detected, and the period of the timer is also changed. In order to restore the respective registers in step 109.

When the initialization routine is performed to detect the touch position of the touch screen 4 as described above, it is determined whether the new coordinate value, that is, the touch position coordinates of the touch screen 4 has been changed in step 200, and the touch is performed. If the position coordinates are changed, the flash buffer routine is performed in step 300.

In the flash buffer routine, as shown in FIG. 2C, each register is evacuated in step 301, a data segment is set in step 302, and the head and tail of the memory map are corrected with start in step 303. The head and tail of the memory map are matched with a start to make the initial state where no data is stored in the memory map, and each register is restored at step 304.

In this manner, when the memory map is initialized or the new map value is not the new coordinate value in step 200, the standby routine is performed in step 400.

In the standby read routine, evacuate each register in step 401, set the data segment in step 402, read the head and tail of the memory map in step 403, as shown in FIG. In 404, the head and the tail are compared, that is, it is determined whether the touch position data of the touch screen 4 is stored in the memory map, and the head and tail are the same, and thus the touch position data is not stored in the memory map. In step 403, the process repeats the process and waits until the touch position data is stored. If the touch position data is stored in the memory map because the head and tail are not the same, the memory map indicated by the head in step 405 is repeated. Reads the X- and Y-axis touch position data of the address of < RTI ID = 0.0 >, < / RTI > and decreases the tail in step 406, or step 408 if the tail position is the end of the memory map in step 407. After standing in a tail to the start of the memory map, and transmits the X-axis and Y-axis touch position data read in step 409, to recover the respective registers at step 410.

As described above, when the touch position data of the touch screen 4 is transmitted by performing the standby read routine, it is determined in step 500 whether the input is terminated, that is, whether the touch of the touch screen 4 is terminated, and not finished. If not, the process is repeated from step 200, and if it is terminated, the disable routine is performed at step 600.

In the disable routine, the respective registers are evacuated in step 601 as shown in FIG. 2E, the head and tail of the memory map are corrected with start in step 602, the vector of timer interrupts in step 603, and the like. After recovering the vector of timer tick interrupts, the vector of timer interrupts is restored in step 604, and each register is restored in step 605, and thus, when it is returned to its original state by performing a destroy routine.

As the timer interrupt signal is applied at regular time intervals while performing the main routine, the timer interrupt routine is performed to store the touch position data of the touch screen 4 in the memory map.

That is, in the timer interrupt routine, each register is evacuated in step 701, the data segment is set in step 702, and the state detection routine is performed in step 703, as shown in FIG.

In the state detection routine, each register is evacuated in step 711, the data segment is set in step 712, and the head and tail of the memory map are read in step 713, as shown in FIG. When the head and the tail are not identical and the touch position data is not stored in the memory map in step 714, the touch position data is stored in the memory map in step 715. If the touch position data is stored in the memory map because the head and the tail are not the same, the storage variable is set to 1 in step 716, and the touch position data is stored in the memory map. In step 717, each register is restored.

When the state detection routine is performed to determine whether touch position data is stored in the memory map, the touch position detection routine is performed in step 720.

In the touch position detection routine, as shown in FIG. 2h, each register is evacuated in step 721, the data segment is set in step 722, and in step 723, the voltage for detecting the X-axis is supplied, that is, X The high potential is output to the axis control terminals XH and XL so that the X-axis detection voltage supply unit 2 supplies the detection voltage to the X-axis of the touch screen 4, and in step 724, the analog-to-digital converter 10 After reading the X-axis touch position data from the X-axis touch position data, it is determined whether the touch screen 4 has been touched by the X-axis touch position data read in step 725, and returned if it has not been touched. ) Outputs a high potential to the Y-axis control terminals (YH, YL) to the Y-axis detection voltage supply unit 3 supplies the detection voltage to the Y-axis of the touch screen 4, the Y-axis touch position in step 727 Reads data, and reads the X-axis and Y-axis touch position data read in step 728. If it has not been detected twice in a mori map after detecting a certain number of times, i.e., detecting twice the X-axis and Y-axis touch position data of the touch screen 4 in step 729, 723, and if detected twice, the average value of the X-axis and Y-axis touch position data read in step 730 is calculated and stored in the memory map in step 731, and each step in step 732. Restore the register.

When the touch position of the touch screen 4 is detected by performing the touch position detection routine as described above, each register is restored and returned in step 740.

On the other hand, Figure 4 is a signal flow diagram showing another embodiment of the touch position detection method of the present invention. As shown in FIG. 4A, the present invention performs the flash buffer routine in step 300 according to the presence of the new coordinate value in step 200 and then does not perform the standby read routine in step 440. If the state of the storage variable indicating whether the touch position data is stored in the map is determined and the storage variable is 0 and the touch position data is not stored in the memory map, step 500 is performed and the storage variable is 1. In the case where touch location data is stored in the memory map, a check read routine is performed in step 450 and step 500 is performed.

In the verify read routine, as shown in FIG. 4B, each register is evacuated in step 451, the data segment is set in step 452, the head and tail of the memory map are read in step 453, and In operation 454, the head and the tail are compared, that is, the touch map data of the touch screen 4 is stored in the memory map and the head and the tail are not stored in the memory map. In step 461, if each register is restored and the head and tail are not the same, and the touch position data is stored in the memory map, the X and Y axes of the address of the memory map indicated by the head in step 456 are Read the touch position data, reduce the tail in step 457, and if the tail's position in step 458 is the end of the memory map, turn the tail to start the memory map in step 459. After that, the X- and Y-axis touch position data read in step 460 is transferred, and each register is restored in step 461.

As described in detail above, according to the present invention, various keyboards may be graphically displayed on the touch screen by detecting the touch position of the touch screen, that is, the keyboard of each device may be used as a data input device such as a modem dial. Of course, there is an effect that can simply input data.

Claims (4)

A microcomputer for controlling the overall operation of the touch position detection of the touch screen, an X-axis and a Y-axis detection voltage supply unit supplying the X-axis and Y-axis detection voltages to the touch screen by the control of the microcomputer, and a touch of the touch screen. An analog / digital converter for converting the voltage output according to the digital signal into the digital signal and outputting the digital signal to the microcomputer, a control signal output unit for controlling the analog / digital converter to operate according to the output signal of the microcomputer, and the analog / digital converter. And a flip-flop for informing the microcomputer that the conversion to the digital signal is completed according to the output signal of the touch screen. An initialization routine that initializes the entire system, changes the vector of timer interrupts and the vector of timer tick interrupts to timer routines and touch screen routines, and then quickly changes the frequency of timer interrupts, and touch screens as new coordinate values are set. Flash buffer routines to calibrate the head and tail of the memory map storing the touch position data at the start, read routines to transmit the touch position data stored in the memory map, and restore the entire system when the touch of the touch screen is terminated. And a status detection routine for determining whether the touch position data is stored in the memory map and a touch position detection routine for detecting the touch position of the touch screen and storing the touch position in the memory map at each timer interrupt. Touch position detection method of the touch screen. The touch screen of claim 2, wherein the read routine is a standby read routine for waiting until touch location data is stored in a memory map, and reading and transmitting the stored touch location data when the touch location data is stored. Touch position detection method. The touch routine of claim 2, wherein the read routine is a confirmation read routine that checks whether touch location data is stored in the memory map at predetermined time intervals, and reads and transmits the touch location data when stored. Method of detecting touch position of screen.

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