CN101908876A - Capacitance type touch key system and micro-control unit thereof - Google Patents
Capacitance type touch key system and micro-control unit thereof Download PDFInfo
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Abstract
The invention discloses a capacitance type touch key system and a micro-control unit thereof. The capacitance type touch key system comprises a comparer, a switching circuit and a charging time data processing module, wherein the positive input end of the comparer is coupled with a reference signal; the switching circuit comprises a first logic control switch, a second logic control switch and a third logic control switch, wherein the first logic control switch and the second logic control switch alternately present a closed state and a open state under the same frequency, and the third logic control switch is controlled by the output signal of the comparer; the charging time data processing module is connected with the output end of the comparer through signals; and the negative input end of the comparer is coupled with a charge-discharge capacitance end, is coupled with a power supply end through the first logic control switch and the second logic control switch, is coupled with a grounding end through the third logic control switch and is coupled with a plurality of touch key ends through the second logic control switch. The system has the advantages of simple peripheral circuit and low cost of the circuit and solves the problems of large temperature drift, high cost, complicated regulation and the like of the traditional capacitance type touch key system.
Description
Technical field
The present invention relates to touch key-press and make the field, particularly relate to a kind of capacitance type touch key system and micro-control unit thereof based on micro-control unit.
Background technology
Touch control according to its principle difference, can be divided into multiple control modes such as electric wave formula, resistance-type, optical profile type, condenser type, inductance type and electromagnetic type.Every kind of control mode has its pluses and minuses and applicable situation separately.Wherein capacitance type touch key only needs a microprocessor and some peripheral circuits just can realize the touch of button is detected and control, thereby is applicable to many household electrical appliance because its circuit is simple relatively.
The basic principle of capacitance type touch key is exactly a relaxation oscillator that constantly charges and discharge.If soft-touch control not, relaxation oscillator has fixing discharging and recharging the cycle, and frequency can be measured.If with the finger contact-making switch, will increase the touch key-press equivalent capacity, the cycle of discharging and recharging will be elongated, and frequency will correspondingly reduce.So, discharge and recharge the variation of cycle or frequency by measurement, just can detect touch action.
Existing capacitance type touch key system, in order to realize charge-discharge circuit, need utilize several resistance and at least one charge and discharge capacitance to realize peripheral circuit, for example, application number is that 200810006684.0 Chinese patent application has just disclosed a kind of peripheral circuit that is made of resistance and charge and discharge capacitance.This peripheral circuit tends to bring temperature to float greatly owing to adopted more components and parts, and the cost height is regulated problems such as complexity.
In addition, the crucial judgment criteria of the performance quality of touch key-press is antijamming capability and sensitivity.Existing touch key system be to the absolute value of button equivalent capacity carry out data value conversion (for example, the electric capacity digital translation, CDC) and handle, and with this benchmark as sub key.And experiment shows that the stray capacitance of printed circuit board (PCB) (PCB) itself and layout can directly have influence on the value size of equivalent capacity, has influence on the sensitivity of sub key then.Therefore, adopt cost based on the sub key method of touch key-press equivalent capacity absolute value be to the higher requirement of pcb board and on software processes the complicated more adjustment algorithm adjustment algorithm of stray capacitance bias (for example, based on).
As seen, existing capacitance type touch key system, peripheral circuit also need some resistance and charge and discharge capacitance except that button, and this peripheral circuit is comparatively complicated, and has brought temperature to float greatly, and the cost height is regulated problems such as complexity.In addition, existing capacitance type touch key system adopts the sub key method based on touch key-press equivalent capacity absolute value, it is had relatively high expectations to pcb board, and on software processes, need complicated more adjustment algorithm, thereby also higher to the requirement of software resource, so system's difficulty on function realizes is big and cost is high.
Summary of the invention
The object of the present invention is to provide a kind of capacitance type touch key system, to solve existing capacitance type touch key system owing to the complicated temperature that causes of peripheral circuit is floated greatly, the cost height is regulated problems such as complexity.
For solving above technical problem, the invention provides a kind of capacitance type touch key micro-control unit, it comprises: comparator, its positive input couples a reference signal; Switching circuit, comprise first logic control switch, second logic control switch and the 3rd logic control switch, wherein first logic control switch and second logic control switch alternately present the closed and disconnected state with same frequency, and the 3rd logic control switch is controlled by the output signal of comparator; Charging interval data processing module, signal connect the output of described comparator; The negative input of described comparator couples a charge and discharge capacitance end; The negative input of described comparator couples a power source supply end by first logic control switch and second logic control switch; The negative input of described comparator couples an earth terminal by the 3rd logic control switch; The negative input of described comparator couples a plurality of touch key-press ends by second logic control switch.
Further, described capacitance type touch key micro-control unit also comprises: the clock delay module, be connected between described comparator output terminal and the charging interval data processing module, and the output signal of comparator is by described the 3rd logic control switch of control after this clock delay module.
Further, described reference signal is many gears adjustable signal.
Further, described first logic control switch and second logic control switch are controlled by same clock signal.
The present invention provides a kind of capacitance type touch key system in addition, comprises micro-control unit and peripheral circuit, and described peripheral circuit comprises a plurality of touch key-presss and a charge and discharge capacitance; Described micro-control unit comprises: comparator, and its positive input couples a reference signal; Switching circuit, comprise first logic control switch, second logic control switch and the 3rd logic control switch, wherein first logic control switch and second logic control switch alternately present the closed and disconnected state with same frequency, and the 3rd logic control switch is controlled by the output signal of comparator; Charging interval data processing module, signal connect the output of described comparator; The negative input of described comparator couples a power source supply end by first logic control switch and second logic control switch; The negative input of described comparator couples an earth terminal by the 3rd logic control switch; The negative input of described comparator couples described a plurality of touch key-press and described charge and discharge capacitance by second logic control switch.
Further, described micro-control unit also comprises: the clock delay module, be connected between described comparator output terminal and the charging interval data processing module, and the output signal of comparator is by described the 3rd logic control switch of control after this clock delay module.
Further, described reference signal is many gears adjustable signal.
Further, described first logic control switch and second logic control switch are controlled by same clock signal.
Further, described charge and discharge capacitance is a tunable capacitor.
Further, the adjustable extent of described charge and discharge capacitance is 2.2nF to 44nF.
Key system of the present invention is compared with traditional key system, and peripheral circuit is simple, need not to utilize resistance can realize that temperature is floated little, regulates simply, and cost is low.
Description of drawings
Fig. 1 is the structured flowchart of the micro-control unit of the capacitance type touch key system that one embodiment of the invention provided;
Fig. 2 is a kind of mode of connection schematic diagram of the peripheral circuit of the touch key-press that one embodiment of the invention provided;
Fig. 3 is the structured flowchart of the micro-control unit of the capacitance type touch key system that a preferred embodiment of the present invention provided;
Fig. 4, it is the schematic flow sheet of the key-judging method for capacitive touch keys that one embodiment of the invention provided.
Embodiment
For purpose of the present invention, feature are become apparent, the specific embodiment of the present invention is further described below in conjunction with accompanying drawing.
The present invention is based on the charge-discharge principle of electric capacity, integrated three logic control switch in the micro-control unit of capacitance type touch key system, open and close the charge and discharge of controlling the charge and discharge capacitance in the peripheral circuit by these logic control switch, thereby need not resistance to be set at peripheral circuit, reduced the complexity of peripheral circuit, solved existing capacitance type touch key system temperature and floated greatly, the cost height is regulated problems such as complexity.
Specifically please refer to Fig. 1, it is the structured flowchart of the capacitance type touch key system that one embodiment of the invention provided.As shown in the figure, the micro-control unit of this system (MCU) 100 comprises comparator 110, switching circuit 120 and charging interval data processing module 130.Wherein switching circuit 120 comprises the first logic control switch SW1, the second logic control switch SW2 and the 3rd logic control switch SW3, wherein the first logic control switch SW1 and the second logic control switch SW2 alternately present the closed and disconnected state with same frequency, and the 3rd logic control switch SW3 is controlled by the output signal of comparator 110.The positive input of comparator couples a reference signal Vref; Its negative input couples a charge and discharge capacitance end PADC; And couple a power source supply end by the first logic control switch SW1 and the second logic control switch SW2, and couple an earth terminal by the 3rd logic control switch SW3, couple a plurality of touch key-press end PAD by the second logic control switch SW2.Charging interval data processing module 130 signals connect the output of comparator 110, to handle the charging interval of charge and discharge capacitance 220.
Above capacitance type touch key system is based on the charge-discharge principle of electric capacity, the first logic control switch SW1, the second logic control switch SW2 and touch key-press equivalent capacity Cxn by micro-control unit 100 inside form equivalent resistance Rx, constitute the RC charge-discharge circuit with charge and discharge capacitance 220, inner the 3rd logic control switch SW3 of output state control by built-in comparator 110 realizes the discharge of charge and discharge capacitance 220.Wherein, after the touch key-press function was opened, under the situation of operate as normal, the high level of the 3rd logic control switch SW3 was held time and is the charging interval of button front and back charge and discharge capacitance 220, also is the time that SW3 keeps off-state.
Please refer to Fig. 2, it is a kind of mode of connection example of the peripheral circuit of above touch key-press, and wherein TK1 to TK20 represents its peripheral 20 touch key-presss, and C is peripheral charge and discharge capacitance.As can be seen from the figure, adopt above structure after, peripheral circuit need not to be provided with resistance again, circuit cost is low, and has simplified the layout and the design of peripheral circuit greatly.And the micro-control unit inner function circuit is realized simple, only needs three logic control switch, and comparator and charging interval data processing module just can be realized.
Know in the superincumbent description that the first logic control switch SW1 and the second logic control switch SW2 need alternately to present the closed and disconnected state with same frequency.In order to realize this control accurately, can in micro-control unit 100, utilize same clock signal fs to realize control to the first logic control switch SW1 and the second logic control switch SW2.Certainly, the present invention not as limit, also can utilize different clock signals to control at this, but it is simple relatively to utilize same clock signal to have control, realizes being easy to advantage.
In addition, it is adjustable that the reference signal Vref that positive input coupled that it should be noted that above comparator 110 can be set to many gears, like this, helps improving the answering property of touch key-press to environment.For example, reference signal Vref has 1/2VDD, 3/5VDD, and 4/5VDD, four adjustable gears of 9/10VDD are chosen the 1/2VDD shelves, and when current supply power voltage was 5V, comparator forward end reference voltage was 2.5V.
In a preferred embodiment, can set up the clock delay module at the output of comparator 110, be used for the output of delaying time of comparator 110 output end signals, to guarantee the effective output of comparator 110 under short-time pulse disturbs.Specifically, please refer to Fig. 3, it is the structured flowchart of the capacitance type touch key system that a preferred embodiment of the present invention provided.As shown in the figure, also be provided with clock delay module 140 in this system, it is connected between comparator 110 outputs and the charging interval data process method 130, and the output signal of comparator 110 is by these clock delay module 140 back controls the 3rd logic control switch SW3.
Come whole this touch key system of describing below in conjunction with Fig. 1 and Fig. 2.As shown in the figure, this system comprises micro-control unit 100 and peripheral circuit.Wherein peripheral circuit comprises a plurality of touch key-presss 210 and a charge and discharge capacitance 220.100 of micro-control units have the described structure of above embodiment.It should be noted that in preferred embodiment charge and discharge capacitance 220 is a tunable capacitor, like this, can make things convenient for the user to improve sub key sensitivity according to the environment needs.For example, its adjustable extent can be 2.2nF to 44nF.
Describe the sub key principle of above touch key system below in detail, i.e. the data processing method of charging interval data processing module 130.
Embodiment one:
With existing touch key-press sub key method,, be applied in the touch key system that above embodiment provides promptly based on the method for the absolute value of button equivalent capacity.Because this sub key method is prior art, and different data processing method (for example, application number is that 200810006684.0 Chinese patent application has just disclosed a kind of implementation) is arranged, therefore, only make simplified summary at this.
As Fig. 1 and shown in Figure 2, Cx is the touch key-press equivalent capacity, forms switched-capacitor circuit with logic control switch SW1, SW2.Wherein, logic control switch SW1 and SW2 can be by same clock controls in MCU inside, and they are with same frequency, regular time difference alternately present the closed and disconnected state.According to the switching capacity characteristic, logic control switch SW1, SW2 and touch key-press equivalent capacity Cx can equivalence be resistance R x.And satisfy:
Rx＝1/(fs×Cx) (1)
Wherein fs is the switching frequency of touch key system, and it is switch logic control switch SW1, SW2 periodically.
Power supply VDD carries out periodicity by switch equivalent resistance Rx to charge and discharge capacitance 220 and discharges and recharges.Before and after button was pressed, the variation that the equivalent capacitance value on the respective keys takes place can cause that switch equivalent resistance Rx changes, thereby causes in the difference of charge and discharge capacitance on 220 charging intervals.The relation in Rx and 220 charging intervals of charge and discharge capacitance is shown below:
As seen, the variation in this charging interval just can be used as the basis for estimation whether button is pressed.Thereby existing sub key method need be set a charge and discharge capacitance charging interval threshold value T.When button was not pressed, touch key-press had a basic electric capacity, and MCU can write down the charging interval to this basic electric capacity charging.When button was pressed, the electric capacity of meeting of the electric capacity of human body and touch key-press was coupled, and made the electric capacity of touch key-press become big, caused its charging interval to become length.In like manner, MCU detects the charging interval when changing to certain threshold value, and judging has button to press.In like manner, can not repeat them here by carrying out sub key discharge time yet.
Antijamming capability and the sensitivity of having mentioned this method in background technology are not desirable especially.Because it is conversion and the processing of button equivalent capacity absolute value being carried out data value, and with this benchmark as sub key.And evidence, the stray capacitance of pcb board itself and layout can directly have influence on the value size of equivalent capacity, have influence on the sensitivity of sub key then.Therefore, to adopt sub key method cost based on touch key-press equivalent capacity absolute value be to the higher requirement of pcb board and increase the complicated adjustment algorithm based on stray capacitance offset value on software processes.System realizes that on function difficulty is big and cost is high.
For this reason, provide a kind of sub key method,, improved the antijamming capability of touch key system, reduced it simultaneously and realize difficulty and cost so that the sensitivity of sub key to be provided based on button equivalent capacity relative value in following examples.Specific as follows:
Embodiment two:
Equally, as Fig. 1 and shown in Figure 2, Cx is the touch key-press equivalent capacity, forms switched-capacitor circuit with logic control switch SW1, SW2.Wherein, logic control switch SW1 and SW2 can be by same clock controls in MCU inside, and they are with same frequency, regular time difference alternately present the closed and disconnected state.According to the switching capacity characteristic, logic control switch SW1, SW2 and touch key-press equivalent capacity Cx can equivalence be resistance R x.And satisfy:
Rx＝1/(fs×Cx) (1)
Wherein fs is the switching frequency of touch key system, and it is switch logic control switch SW1, SW2 periodically.
Power supply VDD carries out the periodicity charging by switch equivalent resistance Rx to charge and discharge capacitance 220.Before and after button was pressed, the variation that the equivalent capacitance value on the respective keys takes place can cause that switch equivalent resistance Rx changes, thereby causes in the difference of charge and discharge capacitance on 220 charging intervals.The relation in Rx and 220 charging intervals of charge and discharge capacitance is shown below:
Wherein Vref is a comparator anode reference input voltage.
During initial condition, built-in comparator 110 positive input reference voltage Vref are higher than negative input, so the output high level.When charge and discharge capacitance 220 charges to negative input voltage when being higher than the positive input reference voltage Vref, the comparator output low level.The output of corresponding comparator 110, system is by the discharge of logic control switch SW3 control charge and discharge capacitance 220 terminal voltages.Holding time of high level of comparator output is the charging interval of charge and discharge capacitance 220, also is the time that SW3 keeps off-state.
In the present embodiment, MCU inside has couple logic control switch SW3 to count, the charging interval of reflecting charge and discharge capacitance 220 by count value (CLK number, promptly what clock cycle the charging interval has).The logic switch SW1 of counting clock signal and RC charge-discharge circuit, SW2 clock signal can be by providing with 1 clock source, and system clock for example is to improve the stability of system.Wherein, counting clock signal often is a clock source signals, and logic switch SW1, SW2 clock signal (switching frequency fs) are then obtained through frequency division by clock source signals, for example 4 frequency divisions, 8 frequency divisions etc.
The clock delay module 140 that it should be noted that the comparator output terminal among Fig. 2 is used for comparator 110 output end signals are carried out adjustable time-delay output, to guarantee the effective output of comparator 110 under short-time pulse disturbs in the system.Time of delay is adjustable to make things convenient for the user under different operating frequencies, selects at disturbing pulse of different nature.Can improve the antijamming capability of system by this mode.
In native system, when initial state charging voltage was 0V, there were following relation in 220 charging intervals of charge and discharge capacitance and changes in capacitance amount Δ Cx corresponding before and after the button:
T1 wherein, t2 are respectively the corresponding charging interval before and after the button, and following formula can further be reduced to:
According to (3) and (4) Shi Kede:
This K is equivalent to an entropy coefficient, has reacted the variation of button front and back touch key-press equivalent capacitys and the relation between its charging interval difference that is caused.
The actual value of K is very complicated, but in the practical application, does not need to be reflected in by actual value the charging interval difference that variation caused of button front and back touch key-press equivalent capacity.Therefore consider following improvement project:
Set up the K value as required on their own by the user, behind each scanning button, K will be worth divided by 220 charging intervals of charge and discharge capacitance (being the count value that logic control switch SW3 keeps the off-state time), the relative quantity (collection value) of touch key-press equivalent capacity can be obtained reflecting by hardware.Relatively the difference of relative quantity (collection value) just can be carried out follow-up sub key processing before and after the button.Specifically, please refer to Fig. 4, it is the schematic flow sheet of the key-judging method for capacitive touch keys that one embodiment of the invention provided.As shown in the figure, comprise the steps:
Step S1: set an entropy coefficient;
Step S2: the scanning button obtains the charge and discharge capacitance count value in first charging interval;
Step S3: utilize the entropy coefficient divided by the count value in first charging interval, obtain reflecting first relative quantity of touch key-press equivalent capacity;
Step S4: scan button once more, obtain the charge and discharge capacitance count value in second charging interval;
Step S5: utilize the entropy coefficient divided by the count value in second charging interval, obtain reflecting second relative quantity of touch key-press equivalent capacity;
Step S6: ask for the difference of second relative quantity and first relative quantity, and utilize this difference to carry out sub key.
As seen, above sub key method comes button is judged that by the charging interval relative variation of asking for button front and back charge and discharge capacitance therefore, the difference of the stray capacitance value on the different pcb board buttons can not impact sub key.Adopt this method, not only realization is simple, and greatly reduces requirement and difficulty to pcb board and software algorithm processing.Only need to realize high-order division arithmetic, can will be converted to the data processing of touch key-press equivalence collection value the charging interval by hardware, simple to operate, fast.
In above step S6, the processing procedure of sub key can be taked the mode of threshold decision equally.That is, set a threshold value, when the difference of second relative quantity and first relative quantity reaches or is higher than this threshold value, judge that button presses; When described difference was lower than this threshold value, the judgement button was not pressed.
Below with Vdd=5V, Vref=1/2Vdd=2.5V, the systematic sampling frequency is clock source signals (frequency 8MHz), C1=6.8nF is that example is illustrated.As shown in table 1, the relative quantity (collection value) of the charging interval count value (CLK number) of correspondence and the touch key-press equivalent capacity of trying to achieve when it is 2 frequency divisions, 4 frequency divisions of clock source signals and 8 frequency divisions for fs of recording of experiment, wherein t1 and t2 represent button front and back charging interval count value respectively, and Δ t then represents the count value difference; Cxa and Cxb act on behalf of the relative quantity of button front and back touch key-press equivalent capacity respectively, and Δ Cx then represents the relative quantity difference.
Table 1
Here need to prove that the actual measured value of Cxa, Cxb and Δ Cx is as shown in bracket is outer, the value of Theoretical Calculation gained is as shown in the bracket, and measured value and theoretical value differ very little as can be seen.
It is as shown in the table, and when fs=4MHz, the charging interval count value that records before the button is 877, and the charging interval count value that records behind the button is 805.Setting K in the present embodiment is 69C79CH (hexadecimal), and corresponding decimal system numerical value is 6932380.Utilize K divided by t1, just can obtain the relative quantity Cxa=7904 of the preceding touch key-press equivalent capacity of button; Utilize K divided by t2 equally, just can obtain the relative quantity Cxb=8611 of touch key-press equivalent capacity behind the button.So, just, can calculate the relative quantity difference DELTA Cx=707 of button front and back.In the present embodiment, setting threshold is 150H (hexadecimal), and corresponding decimal system numerical value is 336.Obviously, at this moment, the value of Δ Cx is pressed so judge button greater than threshold value 336.In like manner, can make judgement,, repeat no more at this to the situation of fs=2MHz and fs=1MHz.Need to prove, be not absolute with choosing of upper threshold value, it is relevant with button collection value, and button collection value can be different different because of external environment (for example differences such as obducent material, thickness on the finger of different people and the touch key-press).For example, when covering crystal silicon plate on the touch key-press, the dielectric constant of corresponding material is bigger, the plank thinner thickness, and then the sub key threshold value can be taken to about 200H, and this threshold value not necessarily is suitable for other materials.So the present invention does not do any restriction at this to threshold setting, those skilled in the art can carry out inside according to the concrete environment of client's pcb board and be provided with.
It should be noted that because Cx and t are inverse relation, same Δ Cx and the Δ t relation that also is inversely proportional to, therefore when the button front and back charging interval poor (Δ t=t2-t1) than hour, cause bigger quantization error easily.Therefore, preferable, K is designed to adjustable, the user can adjust the purpose that dividend reach the lower quantization error according to different Δ t, to strengthen the adaptability of environment.
Regulate as required for ease of the user, with sample frequency be divided into many grades optional, for example 2 frequency divisions, 4 frequency divisions, 8 frequency divisions, 16 frequency divisions, 32 frequency divisions etc. are all or part of.
In addition, as seen from the above table, when the frequency division that fs got was big more, corresponding CLK number was big more.In this case, get 16 by the collection value and calculate, the K value of setting need reach 24 at least.For keeping certain value surplus, improve the resolution of collection value, need the collection value of reality is amplified, therefore, in the present embodiment, system locatees 28 for the K value that is provided with that the user provides.Above method is promptly finished 28 divisions by internal hardware (charging interval data processing module 130), and the value of being gathered is handled so that follow-up data to be provided accurately.
As seen, utilize above method can avoid multiplication and division and floating-point operation relevant in the software.Can significantly reduce taking up room and the complexity of software algorithm of program storage area like this, improve the arithmetic speed that system carries out data processing simultaneously.This mode also helps to be increased every sub key number of taking turns or opens up more complicated combination sub key function.
The sub key method that above embodiment provided not only can be used for the key system that above embodiment provides, the key system that also can be used for other, the present invention at this not as limit, those skilled in the art can be according to above prompting, the charging interval data processing module of design key system utilizes above sub key mode that the state of button is judged.
Below characteristic and advantage and the legacy system of above key system are made comparisons, are presented below:
1, peripheral circuit: traditional capacitance type touch key peripheral circuit comprises several resistance and 1 charge and discharge capacitance, realizes charge-discharge circuit, and temperature is floated greatly, and the cost height is regulated complicated.
And key system of the present invention is compared with traditional key system, and peripheral circuit is simple, need not to utilize resistance can realize that temperature is floated little, regulates simply, and cost is low.
2, the user only need adjust external charging electric capacity, can adjust button sensitivity according to environmental requirement, and adjusting range is well-to-do. (2.2nF～the 44nF scope is adjustable, under the oscillator operating frequency of 10MHz, adopts this system can guarantee to tell the variation of charging interval 1us).
Below the characteristic and advantage of above sub key method and traditional sub key method are made comparisons, are presented below:
1, the improvement on the performance
Traditional scheme: the judgment criteria of the good and bad most critical of the performance of touch key-press is antijamming capability and sensitivity. Traditional touch key system is conversion and the processing of button equivalent capacity absolute value being carried out data value, and with this benchmark as sub key. And evidence, the stray capacitance of pcb board itself and layout can directly have influence on the value size of equivalent capacity, then have influence on the sensitivity of sub key. Therefore, adopting sub key method cost based on touch key-press equivalent capacity absolute value is to process to the higher requirement of pcb board with at software to increase the complicated adjustment algorithm based on stray capacitance offset value. System realizes that in function difficulty is big and cost is high.
The present invention: compare with traditional sub key mode, this sub key method is the charge-discharge principle according to electric capacity in the RC circuit, and by asking for finger before and after the button, the charging interval relative variation of charge and discharge capacitance C1 comes button is judged. Therefore, the difference of the upper stray capacitance value of different pcb board PAD can not impact sub key. Adopt this method, not only realization is simple, and greatly reduces requirement and difficulty to pcb board and software algorithm processing.
2, the improvement on hardware handles
Traditional scheme: the processing speed of touch key-press is subjected to every the take turns port number of sub key and the restriction of software algorithm, and traditional scheme is subjected to the restriction of complicated software Processing Algorithm, and the sub key number is limited.
The present invention: the MCU internal data is processed by hardware and is realized, only needs the user that K value is set before the sub key, high-order division arithmetic can obtain need to the sub key fiducial value. Multiplication and division and the floating-point operation of being correlated with in the software have been avoided. Can greatly reduce like this taking up room and the complexity of software algorithm of program storage area, improve simultaneously system and carried out the arithmetic speed that data are processed. This mode also helps to be increased every sub key number of taking turns or opens up more complicated combination sub key function.
Claims (10)
1. a capacitance type touch key micro-control unit is characterized in that, comprising:
Comparator, its positive input couples a reference signal;
Switching circuit, comprise first logic control switch, second logic control switch and the 3rd logic control switch, wherein first logic control switch and second logic control switch alternately present the closed and disconnected state with same frequency, and the 3rd logic control switch is controlled by the output signal of comparator;
Charging interval data processing module, signal connect the output of described comparator;
The negative input of described comparator couples a charge and discharge capacitance end;
The negative input of described comparator couples a power source supply end by first logic control switch and second logic control switch;
The negative input of described comparator couples an earth terminal by the 3rd logic control switch;
The negative input of described comparator couples a plurality of touch key-press ends by second logic control switch.
2. capacitance type touch key micro-control unit according to claim 1 is characterized in that, also comprises:
The clock delay module is connected between described comparator output terminal and the charging interval data processing module, and the output signal of comparator is by described the 3rd logic control switch of control after this clock delay module.
3. capacitance type touch key micro-control unit according to claim 1 is characterized in that, described reference signal is many gears adjustable signal.
4. capacitance type touch key micro-control unit according to claim 1 is characterized in that, described first logic control switch and second logic control switch are controlled by same clock signal.
5. a capacitance type touch key system comprises micro-control unit and peripheral circuit, it is characterized in that, described peripheral circuit comprises a plurality of touch key-presss and a charge and discharge capacitance;
Described micro-control unit comprises:
Comparator, its positive input couples a reference signal;
Switching circuit, comprise first logic control switch, second logic control switch and the 3rd logic control switch, wherein first logic control switch and second logic control switch alternately present the closed and disconnected state with same frequency, and the 3rd logic control switch is controlled by the output signal of comparator;
Charging interval data processing module, signal connect the output of described comparator;
The negative input of described comparator couples a power source supply end by first logic control switch and second logic control switch;
The negative input of described comparator couples an earth terminal by the 3rd logic control switch;
The negative input of described comparator couples described a plurality of touch key-press and described charge and discharge capacitance by second logic control switch.
6. capacitance type touch key system according to claim 5 is characterized in that, described micro-control unit also comprises:
The clock delay module is connected between described comparator output terminal and the charging interval data processing module, and the output signal of comparator is by described the 3rd logic control switch of control after this clock delay module.
7. capacitance type touch key system according to claim 5 is characterized in that, described reference signal is many gears adjustable signal.
8. capacitance type touch key system according to claim 8 is characterized in that, described first logic control switch and second logic control switch are controlled by same clock signal.
9. capacitance type touch key system according to claim 8 is characterized in that, described charge and discharge capacitance is a tunable capacitor.
10. capacitance type touch key system according to claim 9 is characterized in that, the adjustable extent of described charge and discharge capacitance is 2.2nF to 44nF.
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Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102386906A (en) * | 2011-11-25 | 2012-03-21 | 王寅寅 | Touch-type electronic switch preceding stage |
| CN102420600A (en) * | 2011-12-11 | 2012-04-18 | 陈子杨 | Simple and reliable touch control switch |
| WO2013053106A1 (en) * | 2011-10-11 | 2013-04-18 | 中联重科股份有限公司 | Method and system for outputting key pressing signal |
| CN103297024A (en) * | 2012-03-02 | 2013-09-11 | 珠海格力电器股份有限公司 | Sliding key, control device of sliding key and control method of sliding key |
| CN103389802A (en) * | 2013-07-29 | 2013-11-13 | Tcl集团股份有限公司 | Multichip compatible method and device based on capacitive touch press keys as well as electrical equipment |
| CN104423688A (en) * | 2013-09-03 | 2015-03-18 | 新唐科技股份有限公司 | Induction element |
| CN105007069A (en) * | 2015-06-26 | 2015-10-28 | 深圳市芯海科技有限公司 | Digital to analog converter and multiplexer for capacitance detection |
| CN106911328A (en) * | 2017-04-27 | 2017-06-30 | 陈雪燕 | One kind is without button touch system |
| CN107508586A (en) * | 2017-08-08 | 2017-12-22 | 深圳市锦锐科技有限公司 | A kind of super low-power consumption touch key-press circuit and its application method |
| US10073555B2 (en) | 2013-09-03 | 2018-09-11 | Nuvoton Technology Corporation | Sensing device |
| CN109245753A (en) * | 2018-11-13 | 2019-01-18 | 珠海巨晟科技股份有限公司 | The sub key system of capacitance type touch key |
| CN109274363A (en) * | 2018-11-13 | 2019-01-25 | 珠海巨晟科技股份有限公司 | A kind of sub key system of capacitance type touch key |
| CN110176922A (en) * | 2019-06-21 | 2019-08-27 | 苏州锴威特半导体有限公司 | Capacitance type touch key detection circuit |
| CN111106820A (en) * | 2018-10-26 | 2020-05-05 | 珠海格力电器股份有限公司 | Touch key control system and control method thereof |
| CN111900973A (en) * | 2020-07-09 | 2020-11-06 | 青岛信芯微电子科技股份有限公司 | Touch key detection circuit and detection method based on FPGA |
| WO2021081890A1 (en) * | 2019-10-31 | 2021-05-06 | 深圳市汇顶科技股份有限公司 | Control method, mcu, touch control device, and storage medium |
| CN113054983A (en) * | 2021-03-25 | 2021-06-29 | 深圳前海维晟智能技术有限公司 | Dense capacitive touch key circuit supporting hardware waterproofing |
| CN115333521A (en) * | 2022-08-22 | 2022-11-11 | 深圳市锦锐科技股份有限公司 | Low-power-consumption integrated circuit applied to RC touch key |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101060321A (en) * | 2006-04-19 | 2007-10-24 | 北京希格玛和芯微电子技术有限公司 | Charge transport device, touch induction device and method |
| US20090108914A1 (en) * | 2007-10-31 | 2009-04-30 | Chiphomer Technology Limited | Adaptive capacitive touch sense control circuit |
| CN101764604A (en) * | 2009-10-22 | 2010-06-30 | 深圳和而泰智能控制股份有限公司 | Method for achieving touch key function and device thereof |
-
2010
- 2010-07-23 CN CN 201010235749 patent/CN101908876A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101060321A (en) * | 2006-04-19 | 2007-10-24 | 北京希格玛和芯微电子技术有限公司 | Charge transport device, touch induction device and method |
| US20090108914A1 (en) * | 2007-10-31 | 2009-04-30 | Chiphomer Technology Limited | Adaptive capacitive touch sense control circuit |
| CN101764604A (en) * | 2009-10-22 | 2010-06-30 | 深圳和而泰智能控制股份有限公司 | Method for achieving touch key function and device thereof |
Cited By (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013053106A1 (en) * | 2011-10-11 | 2013-04-18 | 中联重科股份有限公司 | Method and system for outputting key pressing signal |
| CN102386906A (en) * | 2011-11-25 | 2012-03-21 | 王寅寅 | Touch-type electronic switch preceding stage |
| CN102420600A (en) * | 2011-12-11 | 2012-04-18 | 陈子杨 | Simple and reliable touch control switch |
| CN103297024A (en) * | 2012-03-02 | 2013-09-11 | 珠海格力电器股份有限公司 | Sliding key, control device of sliding key and control method of sliding key |
| CN103297024B (en) * | 2012-03-02 | 2016-02-24 | 珠海格力电器股份有限公司 | Slip button and control device thereof and control method |
| CN103389802A (en) * | 2013-07-29 | 2013-11-13 | Tcl集团股份有限公司 | Multichip compatible method and device based on capacitive touch press keys as well as electrical equipment |
| US9898123B2 (en) | 2013-09-03 | 2018-02-20 | Nuvoton Technology Corporation | Sensing device |
| CN104423688A (en) * | 2013-09-03 | 2015-03-18 | 新唐科技股份有限公司 | Induction element |
| TWI511014B (en) * | 2013-09-03 | 2015-12-01 | Nuvoton Technology Corp | Sensing device |
| US10073555B2 (en) | 2013-09-03 | 2018-09-11 | Nuvoton Technology Corporation | Sensing device |
| CN105007069A (en) * | 2015-06-26 | 2015-10-28 | 深圳市芯海科技有限公司 | Digital to analog converter and multiplexer for capacitance detection |
| CN106911328A (en) * | 2017-04-27 | 2017-06-30 | 陈雪燕 | One kind is without button touch system |
| CN107508586A (en) * | 2017-08-08 | 2017-12-22 | 深圳市锦锐科技有限公司 | A kind of super low-power consumption touch key-press circuit and its application method |
| CN111106820A (en) * | 2018-10-26 | 2020-05-05 | 珠海格力电器股份有限公司 | Touch key control system and control method thereof |
| CN109274363B (en) * | 2018-11-13 | 2023-12-08 | 珠海巨晟科技股份有限公司 | Key judging system of capacitive touch key |
| CN109245753A (en) * | 2018-11-13 | 2019-01-18 | 珠海巨晟科技股份有限公司 | The sub key system of capacitance type touch key |
| CN109274363A (en) * | 2018-11-13 | 2019-01-25 | 珠海巨晟科技股份有限公司 | A kind of sub key system of capacitance type touch key |
| CN110176922A (en) * | 2019-06-21 | 2019-08-27 | 苏州锴威特半导体有限公司 | Capacitance type touch key detection circuit |
| CN110176922B (en) * | 2019-06-21 | 2024-02-20 | 苏州锴威特半导体股份有限公司 | Capacitive touch key detection circuit |
| WO2021081890A1 (en) * | 2019-10-31 | 2021-05-06 | 深圳市汇顶科技股份有限公司 | Control method, mcu, touch control device, and storage medium |
| CN111900973A (en) * | 2020-07-09 | 2020-11-06 | 青岛信芯微电子科技股份有限公司 | Touch key detection circuit and detection method based on FPGA |
| CN113054983A (en) * | 2021-03-25 | 2021-06-29 | 深圳前海维晟智能技术有限公司 | Dense capacitive touch key circuit supporting hardware waterproofing |
| CN115333521B (en) * | 2022-08-22 | 2023-09-12 | 深圳市锦锐科技股份有限公司 | Low-power consumption integrated circuit applied to RC touch key |
| CN115333521A (en) * | 2022-08-22 | 2022-11-11 | 深圳市锦锐科技股份有限公司 | Low-power-consumption integrated circuit applied to RC touch key |
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