CN103092454B - Electric resistance type touch screen control circuit and multipoint touch realization method thereof - Google Patents

Abstract

The invention provides a kind of electric resistance type touch screen control circuit and multipoint touch realization method thereof, this electric resistance type touch screen control circuit at least comprises touch-screen driving switch module, touch monitoring modular, analog input signal selects module, AD conversion unit, digital control logic module, internal reference module and oscillator module, it produces touch look-at-me by touching monitoring modular and determines that current touch is that single-point touches or multiple point touching, achieve and do not need change panel module and system hardware and software design can realize the object of multi-point touch on existing four-wire type electric resistance touch screen.

Description

Electric resistance type touch screen control circuit and multipoint touch realization method thereof

Technical field

The present invention relates to a kind of touch screen control circuit and its implementation, particularly relate to a kind of electric resistance type touch screen control circuit and multipoint touch realization method thereof.

Background technology

Touch-screen, as a kind of up-to-date input equipment, is the simplest, convenient current, natural a kind of man-machine interaction mode.Along with use computer growing with each passing day as information source, touch-screen is easy to use with it, sturdy and durable, reaction velocity fast, save the advantages such as space, makes system designers feel more and more to use touch-screen really to have sizable superiority.It giving multimedia with brand-new looks, is extremely attractive brand-new multimedia interactive equipment.According to the principle of work of touch-screen and the medium of transmission information, touch-screen can be divided into following five kinds: resistance-type, condenser type, electromagnetic type, infrared-type and surface acoustic wave type.Wherein resistive touch screen is because know-why is simple, threshold is low, upstream and downstream integration is complete, manufacture craft is mature and stable, cost is low and apply maximum, the widest in various touch-screen.Current resistive touch screen occupies the principal market of touch-screen, and from various kind touch-screen totally, the market share of resistive touch screen has accounted for 60%.

Resistive touch screen is a kind of sensor, and the physical location of touch point (X, Y) in rectangular area is converted to the voltage representing X-coordinate and Y-coordinate by it.A lot of LCD module all have employed resistive touch screen, and this screen can produce screen bias voltage with four lines, five lines, six lines, seven lines or eight lines, the voltage of touch point of simultaneously reading back.Resistive touch screen turns on upper and lower two layers of resistor network, by distribution of resistance to determine the position of spot pressure by pressure.Have four lines, five lines, six lines, seven lines, the various combination of eight line formulas on the market at present, all kinds of all have its relative merits, but with four lines and five lines the most universal.

Fig. 1 is a kind of structural representation of common four-wire type electric resistance touch screen.As shown in Figure 1, four-wire type resistive touch screen structure is as follows: the ITO layer being coated with two-layer transparent, homogeneous conductive on glass or acrylic acid substrate, respectively as X electrode and Y electrode, by the separately insulation of evenly distributed transparent lattice point between them.Wherein the ITO of lower floor and glass substrate adhere to, and the ITO on upper strata is attached in PET film.The positive and negative terminal of X electrode and Y electrode is drawn from two ends respectively by " bus ", and X electrode is mutually vertical with the position of Y electrodes conduct bar, exit X-, and X+, Y-, Y+ have four lines altogether, the origin of four-wire resistance type touch screen title that Here it is.When having object contact touch screen surface and impose certain pressure, the ITO conductive layer generation deformation on upper strata and lower floor ITO come in contact, and this structure can be equivalent to the equivalent electrical circuit of Fig. 2.The X of this touch-screen contact, Y-coordinate can be divided into following two steps to calculate:

1. calculate Y-coordinate, apply driving voltage Vdrive at Y+ electrode, Y-electrode ground connection, X+ electrode obtains the voltage of contact point as exit measurement, due to ITO layer homogeneous conductive, contact voltage and the ratio of driving voltage Vdrive equal contact Y-coordinate and the ratio shielding height, and namely y coordinate in contact is: wherein V _x+for X+ electrode voltage, height _screenfor touch-screen height;

2. calculate X-coordinate, apply driving voltage Vdrive at X+ electrode, X-electrode ground connection, Y+ electrode obtains the voltage of contact point as exit measurement, due to ITO layer homogeneous conductive, contact voltage and the ratio of driving voltage Vdrive voltage equal contact X-coordinate and the ratio shielding width, and namely x coordinate in contact is: wherein V _y+for Y+ electrode voltage, Width _screenfor touch-screen width.

The voltage recorded is converted into digital signal by analog to digital converter (ADC) usually, then carries out simple process and just can be converted to coordinate, judges the physical location of contact.It is when touch-screen there being multiple target that above-mentioned resistive touch screen technology exists a problem, and touch-screen only can report a point, namely lacks the ability of simultaneously following the trail of multiple contact.

Have the technology realizing multiple point touching on the basis of four-wire resistance type touch screen at present to occur, as Biyadi Co Ltd application the patent No. be 200810146683.6 Chinese patent disclose " a kind of recognition methods of touch gestures and device ", it gathers 5 point data by single-point touch screen control circuit, carry out 2 gesture touch recognition devices again, so just MCU software is needed to carry out gesture identification or special processing unit carries out above-mentioned calculating, the large needs of calculated amount take comparatively multiple resource, add the difficulty controlling to detect.

In sum, carry out calculating cause calculated amount large and needs take compared with multiple resource and then the problem increasing the difficulty controlling detection because needing MCU software to carry out gesture identification or special processing unit when the four-wire resistance type touch screen of known prior art realizes multiple point touching, therefore, be necessary the technological means proposing to improve in fact, solve this problem.

Summary of the invention

For overcoming the above-mentioned shortcoming of prior art, fundamental purpose of the present invention is to provide a kind of electric resistance type touch screen control circuit and multipoint touch realization method thereof, it is not changing in existing four-wire resistance type touch screen panel module and system hardware and software design basis and can realize multi-point touch, not only reduce taking of calculated amount and resource, and be easy to control to detect.

For reaching above-mentioned and other object, the invention provides a kind of electric resistance type touch screen control circuit, being applied to a touch-screen system, this touch-screen system at least also comprises a resistive touch screen and a processor, and this electric resistance type touch screen control circuit at least comprises:

Touch-screen driving switch module, is connected with this resistive touch screen, to select different driving switch conductings under the control of Digital Logic control module, for this resistive touch screen provides driving voltage;

Touch monitoring modular, be connected to this touch-screen driving switch module, for monitoring on this resistive touch screen whether have touch, and in time having monitored touch, produce a touch look-at-me to this processor, meanwhile, this touch monitoring modular is also for determining that current touch is that single-point touches or multiple point touching;

Analog input signal selects module, and be connected to the output terminal of this touch-screen drived control switch module, it selects corresponding simulating signal as the input of AD conversion unit under the control of this digital control logic module;

AD conversion unit, is connected to this analog input signal and selects module output terminal, for analog input voltage being converted to digital signal and exporting this digital control logic module to;

Digital control logic module, accepts the order of this processor to control the duty of these other parts of electric resistance type touch screen control circuit, and this digital signal is sent to this processor to carry out coordinate data calculating by a digital interface module;

Internal reference module, for generation of reference signal, it is all connected with this AD conversion unit, this touch-screen driving switch module and this digital control logic module, with the driving voltage of the reference voltage and this resistive touch screen that produce this AD conversion unit module needs under the control of this digital control logic module; And

Oscillator module, for providing clock signal for this electric resistance type touch screen control circuit.

Further, this electric resistance type touch screen control circuit also comprises a noise filter module, be connected to this analog input signal select module output terminal and and AD conversion unit output terminal between, its for this AD conversion unit of filtering export digital signal in noise.

Further, by the change detecting this resistive touch screen electric current, this touch monitoring modular can judge that current touch is that single-point touches or multiple point touching.

Further, when the size of current flowing through this resistive touch screen is constant, for single-point touches; When the size of current flowing through this resistive touch screen changes, it is multiple point touching.

For reaching above-mentioned and other object, the present invention also provides a kind of implementation method of multi-point touch, and be applied to one and at least comprise in the touch-screen system of a resistive touch screen, electric resistance type touch screen control circuit and processor, this implementation method at least comprises the steps:

Touch and interrupt monitoring, this processor has judged whether that touching look-at-me produces;

Touch look-at-me if having to produce, then this processor sends corresponding work order and applies driving voltage to digital control logic module to control touch-screen driving switch module;

Gather touch point voltage;

Judge that current touch is that single-point touches or multiple point touching;

Touch if current touch is single-point, this processor then sends single-point and touches the work order of mode of operation to control this touch-screen driving switch module applying driving voltage;

Gather touch point voltage, and calculate the coordinate of touch point according to a single-point computation model;

If current touch is multiple point touching, the work order that this processor then sends multiple point touching mode of operation applies driving voltage to control this touch-screen driving switch module;

Gather touch point voltage, and calculate the distance between the coordinate at center, touch point and touch point according to a multiple spot computation model.

Further, this single-point computation model is:

$x=\frac{V_{Y+}}{V_{\mathrm{Drive}}}\×{\mathrm{Width}}_{\mathrm{screen}};$ $y=\frac{V_{X+}}{V_{\mathrm{Drive}}}\×{\mathrm{height}}_{\mathrm{screen}}$

Wherein V _x+for the X+ electrode voltage of touch point, height _screenfor touch-screen height, V _y+for Y+ electrode voltage, Width _screenfor touch-screen width.

Further, judging that current touch is that single-point touches or before multiple point touching step, also comprises the steps:

$x=\frac{{V^{\′}}_{Y+}}{V_{\mathrm{Drive}}}\×{\mathrm{Width}}_{\mathrm{screen}};$ $y=\frac{{V^{\′}}_{X+}}{V_{\mathrm{Drive}}}\×{\mathrm{height}}_{\mathrm{screen}};$ ${\mathrm{\ΔV}}_{X+}=\frac{R_{\mathrm{dis}\tan \mathrm{ce}}/2}{R_{\mathrm{ALL}}}\×V_{\mathrm{Drive}};$

Wherein, (x, y) represents the coordinate at center, touch point, V ' _x+be the X+ electrode voltage at two centers, touch point, height _screenfor touch-screen height, V ' _y+be the Y+ electrode voltage at two centers, touch point, Width _screenfor touch-screen width, Δ V _x+be twice voltage difference, R _distancebe the resistance between two touch points, R _aLLfor all resistance of Y-direction.

Further, this multiple spot computation model is: judge whether this touch look-at-me becomes height, interrupts detecting for height then continues to touch; Otherwise, then judge that current touch is that single-point touches or multiple point touching.

Further, after calculating the coordinate of touch point/the calculate distance between the coordinate at center, touch point and touch point, also comprise the steps: to judge whether this touch look-at-me becomes height, for height then terminates this workflow; Otherwise, then continue to judge that current touch is that single-point touches or multiple point touching.

Further, judge that single-point touches or multiple point touching can obtain by detecting the change flowing through this resistive touch screen electric current.

Compared with prior art, a kind of electric resistance type touch screen control circuit of the present invention and multiple point touching implementation method thereof touch the difference (single-point touches or multiple point touching) of interrupting by touching monitoring module monitors, achieve the object that can realize multi-point touch on existing four-wire type electric resistance touch screen, for capacitive touch screen, it can significantly reduce costs (cost is only 1/10th of capacitance touch screen), simplicity of design, peripheral circuit is basic Resistor-Capacitor Unit; Design cycle is short, greatly accelerates the cycle that product is successfully introduced to the market.

Accompanying drawing explanation

Fig. 1 is the structural representation of common four-wire type electric resistance touch screen;

Fig. 2 is the equivalent circuit diagram of Fig. 1;

Fig. 3 is that four-wire resistance type touch screen single-point touches the equivalent circuit diagram with two touch;

Fig. 4 is the system architecture diagram of the touch-screen system of a kind of electric resistance type touch screen control circuit application of the present invention;

Fig. 5 is the system architecture diagram of the preferred embodiment of the electric resistance type touch screen control circuit of the present invention;

Fig. 6 is the multipoint touch realization method process flow diagram of the electric resistance type touch screen control circuit of the present invention.

Embodiment

Below by way of specific instantiation and accompanying drawings embodiments of the present invention, those skilled in the art can understand other advantage of the present invention and effect easily by content disclosed in the present specification.The present invention is also implemented by other different instantiation or is applied, and the every details in this instructions also can based on different viewpoints and application, carries out various modification and change not deviating under spirit of the present invention.

Before explanation present pre-ferred embodiments, first detected the principle of work that the multi-point touch of the present invention is described by two touch: Fig. 3 is that four-wire resistance type touch screen single-point touches the equivalent circuit diagram with two touch, from background technology, when four-wire type touch-screen only having a touch, X+, the conducting of X-driving switch, X-direction applies driving voltage V _drive, the voltage V of the X-direction of touch point is read from Y+ _x+otherwise then Y+ and Y-driving switch conducting, Y-direction applies driving voltage V _drive, the voltage V of touch point Y-direction is read from X+ _y+.

Therefore, the voltage that when single-point touches, X-direction reads is:

$V_{X+}=\frac{R_{\mathrm{bottom}}}{R_{\mathrm{top}}+R_{\mathrm{bottom}}}\×V_{\mathrm{Drive}}=\frac{R_{\mathrm{bottom}}}{R_{\mathrm{ALL}}}\×V_{\mathrm{Drive}}$

And during two touch, now exist two contact points all with X+ conducting, therefore:

$V_{X+}^{\′}\≈\frac{R_{\mathrm{bottom}}^{\′}+R_{\mathrm{dis}\tan \mathrm{ce}}/2}{R_{\mathrm{top}}^{\′}+R_{\mathrm{dis}\tan \mathrm{ce}}+R_{\mathrm{bottom}}^{\′}}\×V_{\mathrm{Drive}}=\frac{R_{\mathrm{bottom}}^{\′}+R_{\mathrm{dis}\tan \mathrm{ce}}/2}{R_{\mathrm{ALL}}}\×V_{\mathrm{Drive}}$

Can find out, due to the resistance R of Y+ to Y- _aLLfor constant, V _drivealso be constant, the actual coordinate being approximately center, two touch points of voltage of therefore X+ reading, and the difference of twice voltage be directly proportional to the distance between two touch points, therefore when two touch, output is the distance between the coordinate at center, two touch points and two touch points.

The system architecture diagram of the touch-screen system that Fig. 4 is applied by a kind of electric resistance type touch screen control circuit of the present invention.As shown in Figure 4, this touch-screen system comprises: resistive touch screen 401, touch screen control circuit 402 and processor 403.

Resistive touch screen 401 is as analog input part, and it is connected to touch screen control circuit 402; Simulating signal for according to the simulating signal detecting the current touch condition obtained and obtain resistive touch screen 401, and is converted to digital signal and exports processor 403 to by touch screen control circuit 402; Processor 403 obtains the coordinate data of touch point by corresponding computation model according to current operation mode.At this, touch screen control circuit 402 is core.

Fig. 5 is the system architecture diagram of the preferred embodiment of the electric resistance type touch screen control circuit of the present invention.As shown in Figure 5, a kind of electric resistance type touch screen control circuit of the present invention comprises touch-screen driving switch module 501, touch monitoring modular 502, analog input signal selection module 503, AD conversion unit 504, digital control logic module 505, digital interface module 506, internal reference module 507 and oscillator module 508.

Touch-screen driving switch module 501 is connected with resistive touch screen 401, be mainly resistive touch screen 401 and drive singal is provided, that is, under the control of Digital Logic control module 505, select different driving switch conductings, think that outside four-wire type touch-screen provides driving voltage V _dRIVE, such as, as under one-site model, two point pattern under different mode of operations, different driving switchs is by conducting, and in present pre-ferred embodiments, resistive touch screen 401 is four-wire resistance type touch screen, touch monitoring modular 502 and be connected to touch-screen driving switch module 501, it is for monitoring on current resistive touch screen whether have touch, if there is touch, the touch signal of then simulating is transferred into and touches monitoring modular 502, touch monitoring modular 502 and can produce a touch look-at-me (TOUCH) to processor 403, here processor 403 can be such as MCU, simultaneously, touch monitoring modular 502 also for determining that current touch is that single-point touches or multiple point touching, specifically, at present pre-ferred embodiments, to determine that single-point touches or two touch, driving voltage in single-point touch situation on whole touch-screen is constant, single-point touches the size that cannot change resistance, therefore size of current is constant, and under two touch, because wherein short circuit part resistance are understood in two touch points, the size of current flowing through touch-screen can change, that is, can judge that current touch is that single-point touches or two touch by the change detecting electric current, analog input signal selects module 503, be connected to touch-screen drived control switch 501 output terminal, it selects corresponding simulating signal as the input of AD conversion unit 504 under the control of digital control logic module 505, such as, when X+/X-direction applies driving voltage, then read the voltage signal of Y+ exit, AD conversion unit 504 is connected to the output terminal that analog input signal selects module 503, for analog input voltage (simulating signal of input) is converted to digital signal and exports digital control logic module 505 to, digital control logic module 505, accepts the order of ppu 403 to control the duty of touch screen control circuit each several part, and digital signal is sent to ppu 403 to carry out coordinate data calculating by digital interface module 506, digital interface module 506, for connecting ppu 403 and digital control logic module 505, transmits operating mode control signals and coordinate data between, internal reference module 507, for generation of reference signal, it is connected with AD conversion unit 504, touch-screen driving switch 501 and digital control logic module 505, produces the reference voltage VREF of AD conversion unit 504 module needs and the driving voltage V of touch-screen under the control of digital control logic module 505 _dRIVE, at this, internal reference module 507 both can use the inner reference voltage produced also can external accurate reference voltage, oscillator module 508, for providing clock signal for whole touch screen control circuit.

In addition, for realizing the present invention better, a kind of electric resistance type touch screen control circuit of the present invention also comprises a noise filter module, it is connected to analog input signal and selects module 503 output terminal and AD conversion unit 504, for the noise in the digital signal that filtering AD conversion unit 504 exports, reduce outside noise to the impact of measuring accuracy.

It should be noted that at this, ppu 403 can be various subsystem, such as mobile phone, panel computer, media player, the hardware system of GPS navigator etc., the difference (single-point touches or two touch) of interrupting is touched according to touch-screen, choose the mode of operation of touch screen control circuit, obtain touch point coordinate information, it can identify all Random seismic field, by special algorithm, action recognition can be carried out according to coordinate and (can amplification be identified, reduce, drag, slide, anticlockwise, right rotation), report multiple spot coordinate position simultaneously.

Fig. 6 is the multipoint touch realization method process flow diagram of the touch-screen system of the present invention.As shown in Figure 6, the multipoint touch realization method of the resistive touchscreen system of the present invention comprises the steps:

Step 601: touch and interrupt detecting, namely processor 403 judges whether touch monitoring modular 502 produces touch look-at-me TOUCH;

Step 602: if touch monitoring modular 502 not produce look-at-me, then continue to touch and interrupt detecting; Otherwise then represent that current touch screen has touch, processor 403 sends corresponding work order by digital interface module 506 and applies driving voltage to digital control logic module 505 to control touch-screen driving switch module 501;

Step 603: gather touch point voltage, and enter step 604;

Step 604, judges whether touch look-at-me TOUCH becomes height, continues to touch interruption detection for height then returns step 501; Otherwise, then judge that current touch is that single-point touches or multiple point touching, specifically, judge that single-point touches or multiple point touching can be obtained by the change detecting electric current, in general, driving voltage in single-point touch situation on whole touch-screen is constant, single-point touches the size that cannot change resistance, and therefore size of current is constant, and under 2 or multiple point touching, due to two or more touch point meeting short circuit part resistance, the size of current flowing through touch-screen can change;

Step 605, if processor 403 judges that current touch is that single-point touches, the work order that then processor 403 sends single-point touch mode of operation by digital interface module 506 applies driving voltage to digital control logic module 505 to control touch-screen driving switch module 501, and enters step 506;

Step 606, gather touch point voltage, calculated the coordinate of touch point by processor 403 according to a single-point computation model, and enter step 509, specifically, this single-point computation model is:

$x=\frac{V_{Y+}}{V_{\mathrm{Drive}}}\×{\mathrm{Width}}_{\mathrm{screen}};$ $y=\frac{V_{X+}}{V_{\mathrm{Drive}}}\×{\mathrm{height}}_{\mathrm{screen}}$

Wherein V _x+for the X+ electrode voltage of touch point, height _screenfor touch-screen height, V _y+for Y+ electrode voltage, Width _screenfor touch-screen width;

Step 607, if processor 403 judges that current touch is multiple point touching, the work order that then processor 403 sends multiple point touching mode of operation by digital interface module 506 applies driving voltage to digital control logic module 505 to control touch-screen driving switch module 501, and enters step 508;

Step 608, gathers touch point voltage, and calculate distance between the coordinate at center, touch point and touch point by processor 403 according to a multiple spot computation model, and enter step 609, here for two touch, this multiple spot computation model is:

$x=\frac{{V^{\′}}_{Y+}}{V_{\mathrm{Drive}}}\×{\mathrm{Width}}_{\mathrm{screen}};$ $y=\frac{{V^{\′}}_{X+}}{V_{\mathrm{Drive}}}\×{\mathrm{height}}_{\mathrm{screen}};$ ${\mathrm{\ΔV}}_{X+}=\frac{R_{\mathrm{dis}\tan \mathrm{ce}}/2}{R_{\mathrm{ALL}}}\×V_{\mathrm{Drive}};$

Wherein, (x, y) represents the coordinate at center, touch point, V ' _x+be the X+ electrode voltage at two centers, touch point, height _screenfor touch-screen height, V ' _y+be the Y+ electrode voltage at two centers, touch point, Width _screenfor touch-screen width, Δ V _x+be twice voltage difference, R _distancebe the resistance between two touch points, R _aLLfor all resistance of Y-direction;

Step 609, judges whether touch look-at-me TOUCH becomes height, if do not become height, then enters step 604 and proceeds multiple point touching judgement, if touch look-at-me TOUCH to become height, then process ends.

Visible, the invention provides the implementation method of a kind of resistive touchscreen system, touch screen control circuit and multiple point touching thereof, namely existing four-wire type electric resistance touch screen can realize multi-point touch, for capacitive touch screen, it can significantly reduce costs (cost is only 1/10th of capacitance touch screen), simplicity of design, peripheral circuit is basic Resistor-Capacitor Unit; Design cycle is short, greatly accelerates the cycle that product is successfully introduced to the market.

The present invention is a kind of electric resistance type touch screen control circuit supporting two touch, can direct compatible single-point resistive touch screen at present, terminal system only need import this controller, on panel module and system hardware and software design, does not need to change completely, can by system application upgrade, two point is become, the use-pattern of this touch screen control circuit and application circuit by single-point, identical with traditional resistive, and be that hardware realizes 2 touch detections, the non-MCU software simulation of its effect can be compared.

Claims (8)

1. an electric resistance type touch screen control circuit, is applied to a touch-screen system, and this touch-screen system at least also comprises a four-wire type touch screens and a processor, and this electric resistance type touch screen control circuit at least comprises:

Touch-screen driving switch module, is connected with this four-wire type touch screens, to select different driving switch conductings under the control of Digital Logic control module, for this four-wire type touch screens provides driving voltage;

Touch monitoring modular, be connected to this touch-screen driving switch module, for monitoring on this four-wire type touch screens whether have touch, and in time having monitored touch, produce a touch look-at-me to this processor, meanwhile, this touch monitoring modular is also for determining that current touch is that single-point touches or multiple point touching; By the change detecting this four-wire type touch screens electric current, this touch monitoring modular can judge that current touch is that single-point touches or multiple point touching;

Analog input signal selects module, and be connected to the output terminal of this touch-screen drived control switch module, it selects corresponding simulating signal as the input of AD conversion unit under the control of this digital control logic module;

AD conversion unit, is connected to this analog input signal and selects module output terminal, for analog input voltage being converted to digital signal and exporting this digital control logic module to;

Digital control logic module, accepts the order of this processor to control the duty of these other parts of electric resistance type touch screen control circuit, and this digital signal is sent to this processor to carry out coordinate data calculating by a digital interface module;

Internal reference module, for generation of reference signal, it is all connected with this AD conversion unit, this touch-screen driving switch module and this digital control logic module, with the driving voltage of the reference voltage and this four-wire type touch screens that produce this AD conversion unit module needs under the control of this digital control logic module; And

Oscillator module, for providing clock signal for this electric resistance type touch screen control circuit.

2. electric resistance type touch screen control circuit as claimed in claim 1, it is characterized in that: this electric resistance type touch screen control circuit also comprises a noise filter module, be connected to this analog input signal select module output terminal and and AD conversion unit output terminal between, its for this AD conversion unit of filtering export digital signal in noise.

3. electric resistance type touch screen control circuit as claimed in claim 1, is characterized in that: when the size of current flowing through this four-wire type touch screens is constant, for single-point touches; When the size of current flowing through this four-wire type touch screens changes, it is multiple point touching.

4. an implementation method for multi-point touch, be applied to one and at least comprise in the touch-screen system of a four-wire type touch screens, electric resistance type touch screen control circuit and processor, this implementation method at least comprises the steps:

Touch and interrupt monitoring, this processor has judged whether that touching look-at-me produces;

Touch look-at-me if having to produce, then this processor sends corresponding work order and applies driving voltage to digital control logic module to control touch-screen driving switch module;

Gather touch point voltage;

By judging that current touch is that single-point touches or multiple point touching by detecting the change flowing through this four-wire type touch screens electric current;

Touch if current touch is single-point, this processor then sends single-point and touches the work order of mode of operation to control this touch-screen driving switch module applying driving voltage;

Gather touch point voltage, and calculate the coordinate of touch point according to a single-point computation model;

If current touch is multiple point touching, the work order that this processor then sends multiple point touching mode of operation applies driving voltage to control this touch-screen driving switch module;

Gather touch point voltage, and calculate the distance between the coordinate at center, touch point and touch point according to a multiple spot computation model.

5. the implementation method of multi-point touch as claimed in claim 4, is characterized in that: this single-point computation model is:

$x=\frac{V_{Y+}}{V_{Drive}}\×{\mathrm{Width}}_{screen};y=\frac{V_{X+}}{V_{Drive}}\×{\mathrm{height}}_{screen}$

Wherein V _x+for the X+ electrode voltage of touch point, height _screenfor touch-screen height, V _y+for Y+ electrode voltage, Width _screenfor touch-screen width.

6. the implementation method of multi-point touch as claimed in claim 4, is characterized in that: judging that current touch is that single-point touches or before multiple point touching step, also comprises the steps:

$x=\frac{{V^{\′}}_{Y+}}{r_{Drive}}\×{\mathrm{Width}}_{screen};y=\frac{{V^{\′}}_{X+}}{V_{Drive}}\×{\mathrm{height}}_{screen};{\mathrm{\ΔV}}_{X+}=\frac{R{dis\tan ce}_{}/2}{R_{ALL}}\×V_{Drive};$

Wherein, (x, y) represents the coordinate at center, touch point, V' _x+be the X+ electrode voltage at two centers, touch point, height _screenfor touch-screen height, V' _y+be the Y+ electrode voltage at two centers, touch point, Width _screenfor touch-screen width, Δ V _x+be twice voltage difference, R _distancebe the resistance between two touch points, R _aLLfor all resistance of Y-direction.

7. the implementation method of multi-point touch as claimed in claim 4, is characterized in that: this multiple spot computation model is: judge whether this touch look-at-me becomes height, interrupts detecting for height then continues to touch; Otherwise, then judge that current touch is that single-point touches or multiple point touching.

8. the implementation method of multi-point touch as claimed in claim 4, it is characterized in that: after calculating the coordinate of touch point/the calculate distance between the coordinate at center, touch point and touch point, also comprise the steps: to judge whether this touch look-at-me becomes height, for height then terminates this workflow; Otherwise, then continue to judge that current touch is that single-point touches or multiple point touching.