CN102857232A - Key detection circuit and key detection method - Google Patents
Key detection circuit and key detection method Download PDFInfo
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- CN102857232A CN102857232A CN2012103450966A CN201210345096A CN102857232A CN 102857232 A CN102857232 A CN 102857232A CN 2012103450966 A CN2012103450966 A CN 2012103450966A CN 201210345096 A CN201210345096 A CN 201210345096A CN 102857232 A CN102857232 A CN 102857232A
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Abstract
The invention discloses a key detection circuit comprising a central processing unit MCU (microprogrammed control unit), n2 keys and a power source. The central processing unit MCU is provided with n general purpose input/output (GPIO) interfaces. The n2 keys are arranged according to a SW<nxn> matrix. A key detection circuit comprises n2 detection lines: when all GPIO interfaces are input interfaces, the GPIO<i> is earthed via the key SW1m to form a SW<1m> detection line; when the GPIO<i> is an output interface while the GPIO<1> to GPIO<i-1> and the GPIO<i+1> to the GPIO <n> are respectively connected with the GPIO <i> to form n-1 detection lines via SW<2i>, SW<3i>, SW<4i>...and SW<ni>, and the detection lines are used for detecting the SW<2i>, the SW<3i>, the SW<4i>...and the SW<ni>. The key detection circuti can realize real-time scanning of a great quantity of keys without many GPIOs, system resources can be greatly saved, production cost is reduced, and the key detection circuit has the advantages of high reliability and applicability.
Description
Technical field
The present invention relates to by key technology, relate in particular to a kind of key press detecting circuit.
Background technology
When the universal input/output interface (being called for short GPIO) of a system is less, usually can only support less button, and the number of GPIO is identical with the number that detects button.As being 3 when the number of GPIO, the number of button also is 3, can only realize by increasing additional device so need to increase the button that can identify when not changing the GPIO number, so that circuit design is complicated, production cost is also high simultaneously, and practicality is lower.The existing matrix-scanning circuit that adopts on the market can be realized by 6 GPIO the real-time detection of 9 buttons, but still needs more GPIO number to realize the real time scan of button like this, and practicality is still not strong, and production cost is higher.
Therefore be necessary to provide a kind of simplicity of design, reliability is high, and very big conserve system resources, the key press detecting circuit that reduces production costs.
Summary of the invention
The purpose of this invention is to provide a kind of simplicity of design, reliability is high, and very big conserve system resources, the key press detecting circuit that reduces production costs.。
According to an aspect of the present invention, provide a kind of key press detecting circuit, comprised central processor MCU, some buttons and power supply, described central processor MCU is provided with n universal input/output interface GPIO, it is characterized in that:
The number of described button is n
2Individual, described n
2Individual button is pressed SW
N * nMatrix arrangements, wherein, n is the integer greater than 1;
Described button detection line comprises n
2The bar detection line, particularly,
Each universal input/output interface GPIO is input interface, and GPIOi is by button SW
1mGround connection formation detects SW
1mDetection line, wherein m is 1 to the natural number of n;
GPIOi is output interface, GPIO
1-GPIO
I-1, and GPIO
I+1-GPIO
nBe input interface, GPIO
1-GPIO
I-1And GPIO
I+1-GPIO
nPass through respectively SW
2i, SW
3i, SW
4iSW
NiWith GPIO
iConnect and compose n-1 bar detection line, be used for realizing button SW
2i, SW
3i, SW
4i... SW
NiDetection, wherein, i is 1 to the natural number of n.
As preferably, GPIO
iBy button SW
1iGround connection consists of in the detection line, GPIO
iWith button SW
1iBetween be provided with diode, be used for preventing that the testing circuit electric current from pouring in down a chimney and damage universal input/output interface GPIO
i
Further, be provided with pull-up resistor between described each GPIO and the power supply.
Wherein, described n is 2.
Perhaps, described n is 3.
According to invention on the other hand, provide a kind of detection method of key press detecting circuit, wherein, described key press detecting circuit comprises central processor MCU, n
2Individual button and power supply, described central processor MCU are provided with n universal input/output interface GPIO, described n
2Individual button is pressed SW
N * nMatrix arrangements, wherein, n is the integer greater than 1, described key detecting method may further comprise the steps:
Central processor MCU is controlled the input/output state of each GPIO;
When needs detect button SW
1iThe time, central processor MCU is controlled each GPIO and is input interface, GPIO
iWith button SW
1iButton SW on the detection line that consists of
1iBe scanned, if GPIO
iBe low level, then represent button SW
1iBe pressed, wherein, i is 1 to n natural number, in this step, realizes the scanning to n button of the first row in the key-press matrix;
When needs detect button SW
2i, SW
3i, SW
4iSW
NiThe time, central processing unit control GPIO
iBe output interface, GPIO
1-GPIO
I-1, and GPIO
I+1-GPIO
nBe input interface, button SW
2i, SW
3i, SW
4i... SW
NiBe scanned, if GPIO
1-GPIO
I-1, GPIO
I+1-GPIO
nIn GPIO interface when being low level, button SW then
2i, SW
3i, SW
4iSW
NiIn represent to be pressed with the corresponding button of GPIO interface, wherein, i is 1 to the natural number of n, in this step, the individual button of n* (n-1) except the first row in the key-press matrix is scanned.
Particularly, the number of n is 3.
Three GPIO interfaces of described central processor MCU setting to the detecting step of 9 buttons are:
When three GPIO are input interface, GPIO
1, GPIO
2, GPIO
3Respectively with button SW
11, SW
12, SW
13Button SW on the detection line that consists of
11, SW
12, SW
13Be scanned GPIO
1Be low level, then represent button SW
11Be pressed; GPIO
2Be low level, then represent button SW
12Be pressed; GPIO
3Be low level, then represent button SW
13Be pressed;
Work as GPIO
1Be output interface, GPIO
2, GPIO
3During for input interface, button SW
21, SW
31Be scanned, work as GPIO
2During for low level, then represent SW
21Be pressed, work as GPIO
3During for low level, then represent SW
31Be pressed;
Work as GPIO
2Be output interface, GPIO
1, GPIO
3During for input interface, button SW
22, SW
32Be scanned, work as GPIO
1During for low level, then represent SW
22Be pressed, work as GPIO
3During for low level, then represent SW
32Be pressed;
Work as GPIO
3Be output interface, GPIO
1, GPIO
2During for input interface, button SW
23, SW
33Be scanned, work as GPIO
1During for low level, then represent SW
23Be pressed, work as GPIO
2During for low level, then represent SW
33Be pressed.
By above technical scheme as can be known, the central processing unit of key press detecting circuit arranges n GPIO interface among the present invention, can realize n by the key press detecting circuit among the present invention and key detecting method n GPIO interface
2The detection of individual button.Therefore the present invention does not need more GPIO number just can realize the real time scan of a large amount of buttons, and greatly conserve system resources reduces production costs, and simultaneously the present invention has advantages of that also reliability is high, applicability is strong.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, below will do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art.Apparently, the accompanying drawing in below describing only is some embodiments of the present invention, for those of ordinary skills, can also obtain according to these accompanying drawing illustrated embodiments other embodiment and accompanying drawing thereof.
Fig. 1 shows central processing unit the circuit diagram that two GPIO Interface realizations detect 4 buttons is set;
Fig. 2 shows central processing unit the circuit diagram that three GPIO Interface realizations detect 9 buttons is set.
Embodiment
For making purpose of the present invention, technical scheme and advantage clearer, referring to the accompanying drawing embodiment that develops simultaneously, the present invention is described in more detail.
Embodiments of the invention provide a kind of key press detecting circuit.Described key press detecting circuit comprises central processor MCU, some buttons and power supply.N universal input/output interface GPIO is set on the central processor MCU.Be provided with pull-up resistor between each GPIO and the power supply.Correspondingly the number of button is n in the key press detecting circuit
2Individual.The key press detecting circuit of the present embodiment utilizes n universal input/output interface GPIO to pass through n
2The bar detection line is realized n
2The detection of individual button.
Particularly, n
2Individual button is pressed SW
N * nMatrix arrangements.Wherein, n is the integer greater than 1.
Described n
2The bar detection line is specially:
When each universal input/when output interface GPIO was input interface, GPIOi was by button SW
1mGround connection consists of SW
1mDetection line.Wherein, m is 1 to n natural number.Be GPIO
1Pass through SW
11Ground connection, GPIO
2Pass through SW
12Ground connection, GPIO
3Pass through SW
13Ground connection, by that analogy, GPIO
nPass through SW
1nGround connection consists of n bar detection line, realizes SW respectively
11, SW
12, SW
13SW
1nDetection.As preferably, GPIO
iBy button SW
1iIn the n bar detection line that ground connection consists of, GPIO
iWith button SW
1iBetween be provided with diode, be used for preventing that the testing circuit electric current from pouring in down a chimney and damage universal input/output interface GPIO
i
When GPIOi is output interface, GPIO
1-GPIO
I-1, and GPIO
I+1-GPIO
nBe input interface, the time GPIO
1-GPIO
I-1And GPIO
I+1-GPIO
nPass through respectively SW
2i, SW
3i, SW
4i... SW
NiWith GPIO
iConnect and compose n-1 bar detection line, be used for realizing button SW
2i, SW
3i, SW
4i... SW
NiDetection, wherein, i is 1 to the natural number of n.
When the i value is 1, i.e. GPIO
1Be output interface, then GPIO
2, GPIO
3, GPIO
4GPIO
nPass through respectively SW
21, SW
31, SW
41... SW
N1With GPIO
1Connect and compose n-1 bar detection line, thereby realize SW
21, SW
31, SW
41... SW
N1Detection.
When the i value is 2, i.e. GPIO
2Be output interface, then GPIO
1, GPIO
3, GPIO
4GPIO
nPass through respectively SW
22, SW
32, SW
42SW
N2With GPIO
2Connect and compose n-1 bar detection line, thereby realize SW
22, SW
32, SW
42... SW
N2Detection.
By parity of reasoning,
When the i value is n, i.e. GPIO
nBe output interface, then GPIO
1, GPIO
2, GPIO
3GPIO
N-1Pass through respectively SW
2n, SW
3n, SW
4nSW
NnWith GPIO
nConnect and compose n-1 bar detection line, thereby realize SW
2n, SW
3n, SW
4nSW
NnDetection.
Therefore be input interface and a GPIO is input interface as each GPIO, when other n-1 GPIO is two states of output interface, have n+n* (n-1)=n+n
2-n=n
2The bar testing circuit arranges respectively a button on every testing circuit, thereby realizes n by key press detecting circuit
2The detection of individual button.
The detection method that regards to down the key press detecting circuit of the embodiment of the invention is described in detail.The detection method of key circuit may further comprise the steps:
Central processor MCU is controlled the input/output state of each GPIO;
When detecting SW
11, SW
12, SW
13SW
1nKey-press status the time, central processor MCU is controlled each GPIO and is input interface, GPIO
iWith button SW
1iButton SW on the detection line that consists of
1iBe scanned, if GPIO
iBe low level, then represent button SW
1iBe pressed, wherein, i is 1 to n natural number, in this step, realizes n button SW to the first row in the key-press matrix
11, SW
12, SW
13SW
1nScanning;
When detecting SW
2i, SW
3i, SW
4iSW
NiKey-press status the time, central processor MCU control GPIO
iBe output interface, GPIO
1-GPIO
I-1, and GPIO
I+1-GPIO
nDuring for input interface, button SW
2i, SW
3i, SW
4i... SW
NiBe scanned, if GPIO
1-GPIO
I-1, GPIO
I+1-GPIO
nIn any GPIO interface when being low level, then corresponding button represents to be pressed, wherein, i is 1 to n natural number, in this step, the individual button of the n* in the key-press matrix except the first row (n-1) is scanned.
Utilize the testing circuit among the present invention, when central processor MCU arranges two GPIO interfaces, can realize the real-time detection of 4 buttons; When central processor MCU arranges three GPIO interfaces, can realize the real-time detection of 9 buttons; When central processor MCU arranges four GPIO interfaces, can realize the real-time detection of 16 buttons.
The below illustrates testing circuit structure of the present invention and detection method with two embodiment.
Embodiment 1:
Fig. 1 shows central processing unit the circuit diagram that two GPIO Interface realizations detect 4 buttons is set.As shown in Figure 1,
Key press detecting circuit comprises central processor MCU, 4 button SW
11, SW
12, SW
21, SW
22And power supply, central processor MCU is provided with GPIO
1, GPIO
2Two GPIO interfaces, GPIO
1, GPIO
2Respectively by pull-up resistor R
1, R
2Link to each other with power supply.GPIO wherein
1, GPIO
2Consist of 4 testing circuits.
Work as GPIO
1, GPIO
2When being input interface: GPIO
1, GPIO
2Respectively by button SW
11, SW
12Ground connection consists of 2 detection lines;
Work as GPIO
1Be output interface, GPIO
2During for input interface: GPIO
2Pass through SW
21With GPIO
1Consist of and detect SW
21Detection line;
Work as GPIO
2Be output interface, GPIO
1During for input interface: GPIO
1Pass through SW
22With GPIO
2Consist of and detect SW
22Detection line;
Article 4, detection line is realized real time scan and the detection to 4 buttons.
The below is described in detail the detection method of key press detecting circuit to 4 buttons.
When needs detect SW
11, SW
12The time, central processor MCU control GPIO
1, GPIO
2Be input interface, GPIO
1, GPIO
2With button SW
11, SW
12Button SW on the detection line that consists of
11, SW
12Be scanned.If GPIO
1During for low level, then represent button SW
11Be pressed; GPIO
2Be low level, then represent button SW
12Be pressed.
When needs detect SW
21The time, central processor MCU control GPIO
1Be output interface, GPIO
2Be input interface, button SW
21Be scanned, if GPIO
2Be low level, then represent SW
21Be pressed.
When needs detect SW
22The time, central processor MCU control GPIO
2Be output interface, GPIO
1Be input interface, button SW
22Be scanned, if GPIO
1Be low level, then represent SW
22Be pressed.
This moment, electric circuit inspection was complete, and 4 buttons are all detected.
Key press detecting circuit on the market can only be realized the detection of two buttons by two GPIO interfaces, the testing circuit among the present invention then can be realized the detection of 4 buttons.
Embodiment 2:
Fig. 2 shows central processing unit the circuit diagram that three GPIO Interface realizations detect 9 buttons is set.As shown in Figure 2, key press detecting circuit comprises central processor MCU, 9 buttons and power supply, and central processor MCU is provided with GPIO
1, GPIO
2, GPIO
3Three GPIO interfaces, GPIO
1, GPIO
2, GPIO
3Respectively by pull-up resistor R
1, R
2, R
3Link to each other with power supply.GPIO wherein
1, GPIO
2, GPIO
3Three GPIO interfaces consist of 9 testing circuits.
When three GPIO are input interface: GPIO
1, GPIO
2, GPIO
3Respectively by button SW
11, SW
12, SW
13Ground connection consists of 3 detection lines;
Work as GPIO
1Be output interface, GPIO
2, GPIO
3During for input interface: GPIO
2Pass through SW
21With GPIO
1Consist of and detect SW
21Detection line; GPIO
3Pass through SW
31With GPIO
1Consist of and detect SW
31Detection line;
Work as GPIO
2Be output interface, GPIO
1, GPIO
3During for input interface: GPIO
1Pass through SW
22With GPIO
2Consist of and detect SW
22Detection line; GPIO
3Pass through SW
32With GPIO
2Consist of and detect SW
32Detection line;
Work as GPIO
3Be output interface, GPIO
1, GPIO
2During for input interface, GPIO
1Pass through SW
23With GPIO
3Consist of and detect SW
23Detection line; GPIO
2Pass through SW
33With GPIO
3Consist of and detect SW
33Detection line.
9 circuits are realized real time scan and the detection to 9 buttons thus.
The below is described in detail the detection method of key press detecting circuit to 9 buttons.
When needs detect SW
11, SW
12, SW
13The time, central processor MCU control GPIO
1, GPIO
2, GPIO
3Be input interface, GPIO
1, GPIO
2, GPIO
3With button SW
11, SW
12, SW
13Button SW on the detection line that consists of
11, SW
12, SW
13Be scanned.If GPIO
1During for low level, then represent button SW
11Be pressed; GPIO
2Be low level, then represent button SW
12Be pressed; GPIO
3Be low level, then represent button SW
13Be pressed.
When needs detect SW
21, SW
31The time, central processor MCU control GPIO
1Be output interface, GPIO
2, GPIO
3Be input interface, button SW
21, SW
31Be scanned, if GPIO
2Be low level, then represent SW
21Be pressed; If GPIO
3Be low level, then represent SW
31Be pressed.
When needs detect SW
22, SW
32The time, central processor MCU control GPIO
2Be output interface, GPIO
1, GPIO
3Be input interface, button SW
22, SW
32Be scanned, if GPIO
1Be low level, then represent SW
22Be pressed; If GPIO
3During for low level, then represent SW
32Be pressed.
When needs detect SW
23, SW
33The time, central processor MCU control GPIO
3Be output interface, GPIO
1, GPIO
2Be input interface, button SW
23, SW
33Be scanned, if GPIO
1Be low level, then represent SW
23Be pressed, if GPIO
2Be low level, then represent SW
33Be pressed.
This moment, electric circuit inspection was complete, and 9 buttons are all detected.
Because the detection of the button of 16 and above number is seldom used on the market, so repeat no more herein to 16 buttons of 4 GPIO Interface realizations and greater than the real-time detection method of the button of 4 above GPIO Interface realization respective number among the present invention.
By above technical scheme as can be known, the key press detecting circuit among the present invention can pass through n GPIO Interface realization n
2The detection of individual button.Therefore do not need more GPIO number just can realize the real time scan of a large amount of buttons, greatly conserve system resources reduces production costs, and simultaneously the present invention has advantages of that also reliability is high, applicability is strong.
The above is preferred embodiment of the present invention only, is not for limiting protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of doing, be equal to and replace and improvement etc., all should be included within protection scope of the present invention.
Claims (8)
1. a key press detecting circuit comprises central processor MCU, some buttons and power supply, and described central processor MCU is provided with n universal input/output interface GPIO, it is characterized in that:
The number of described button is n
2Individual, described n
2Individual button is pressed SW
N * nMatrix arrangements, wherein, n is the integer greater than 1;
Described button detection line comprises n
2The bar detection line, particularly,
Each universal input/output interface GPIO is input interface, and GPIOi is by button SW
1mGround connection formation detects SW
1mDetection line, wherein m is 1 to the natural number of n;
GPIOi is output interface, GPIO
1-GPIO
I-1, and GPIO
I+1-GPIO
nBe input interface, GPIO
1-GPIO
I-1And GPIO
I+1-GPIO
nPass through respectively SW
2i, SW
3i, SW
4iSW
NiWith GPIO
iConnect and compose n-1 bar detection line, be used for realizing button SW
2i, SW
3i, SW
4i... SW
NiDetection, wherein, i is 1 to the natural number of n.
2. key press detecting circuit as claimed in claim 1, wherein, GPIO
iBy button SW
1iGround connection consists of in the detection line, GPIO
iWith button SW
1iBetween be provided with diode, be used for preventing that the testing circuit electric current from pouring in down a chimney and damage universal input/output interface GPIO
i
3. key press detecting circuit as claimed in claim 1 wherein, is provided with pull-up resistor between described each GPIO and the power supply.
4. such as the described key press detecting circuit of one of claims 1 to 3, wherein, described n is 2.
5. such as the described key press detecting circuit of one of claims 1 to 3, wherein, described n is 3.
6. the detection method of a key press detecting circuit, wherein, described key press detecting circuit comprises central processor MCU, n
2Individual button and power supply, described central processor MCU are provided with n universal input/output interface GPIO, described n
2Individual button is pressed SW
N * nMatrix arrangements, wherein, n is the integer greater than 1, described key detecting method may further comprise the steps:
Central processor MCU is controlled the input/output state of each GPIO;
When needs detect button SW
1iThe time, central processor MCU is controlled each GPIO and is input interface, GPIO
iWith button SW
1iButton SW on the detection line that consists of
1iBe scanned, if GPIO
iBe low level, then represent button SW
1iBe pressed, wherein, i is 1 to n natural number, in this step, realizes the scanning to n button of the first row in the key-press matrix;
When needs detect button SW
2i, SW
3i, SW
4iSW
NiThe time, central processing unit control GPIO
iBe output interface, GPIO
1-GPIO
I-1, and GPIO
I+1-GPIO
nBe input interface, button SW
2i, SW
3i, SW
4i... SW
NiBe scanned, if GPIO
1-GPIO
I-1, GPIO
I+1-GPIO
nIn GPIO interface when being low level, button SW then
2i, SW
3i, SW
4iSW
NiIn represent to be pressed with the corresponding button of GPIO interface, wherein, i is 1 to the natural number of n, in this step, the individual button of n* (n-1) except the first row in the key-press matrix is scanned.
7. detection method as claimed in claim 6, wherein, the number of n is 3.
8. detection method as claimed in claim 7, wherein, three GPIO interfaces of described central processor MCU setting to the detecting step of 9 buttons are:
When three GPIO are input interface, GPIO
1, GPIO
2, GPIO
3Respectively with button SW
11, SW
12, SW
13Button SW on the detection line that consists of
11, SW
12, SW
13Be scanned GPIO
1Be low level, then represent button SW
11Be pressed; GPIO
2Be low level, then represent button SW
12Be pressed; GPIO
3Be low level, then represent button SW
13Be pressed;
Work as GPIO
1Be output interface, GPIO
2, GPIO
3During for input interface, button SW
21, SW
31Be scanned, if GPIO
2Be low level, then represent SW
21Be pressed, if GPIO
3Be low level, then represent SW
31Be pressed;
Work as GPIO
2Be output interface, GPIO
1, GPIO
3During for input interface, button SW
22, SW
32Be scanned, if GPIO
1Be low level, then represent SW
22Be pressed, if GPIO
3Be low level, then represent SW
32Be pressed;
Work as GPIO
3Be output interface, GPIO
1, GPIO
2During for input interface, button SW
23, SW
33Be scanned, if GPIO
1Be low level, then represent SW
23Be pressed, if GPIO
2Be low level, then represent SW
33Be pressed.
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CN104951098A (en) * | 2014-03-24 | 2015-09-30 | 发那科株式会社 | Matrix key input interface |
CN109190419A (en) * | 2018-09-03 | 2019-01-11 | 深圳福鸽科技有限公司 | Key encrypted circuit and method |
CN112200584A (en) * | 2020-11-05 | 2021-01-08 | 加减信息科技(深圳)有限公司 | Input circuit of payment acceptance terminal |
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CN1981439A (en) * | 2004-07-08 | 2007-06-13 | 赛普拉斯半导体公司 | Method and apparatus for scanning a key or button matrix |
CN101079637A (en) * | 2007-05-24 | 2007-11-28 | 四川长虹电器股份有限公司 | Key system and its detection method |
CN202841104U (en) * | 2012-09-17 | 2013-03-27 | 青岛海信宽带多媒体技术有限公司 | Button detection circuit |
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CN1981439A (en) * | 2004-07-08 | 2007-06-13 | 赛普拉斯半导体公司 | Method and apparatus for scanning a key or button matrix |
CN101079637A (en) * | 2007-05-24 | 2007-11-28 | 四川长虹电器股份有限公司 | Key system and its detection method |
CN202841104U (en) * | 2012-09-17 | 2013-03-27 | 青岛海信宽带多媒体技术有限公司 | Button detection circuit |
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CN104951098A (en) * | 2014-03-24 | 2015-09-30 | 发那科株式会社 | Matrix key input interface |
CN104951098B (en) * | 2014-03-24 | 2018-12-28 | 发那科株式会社 | Matrix form key input interface |
CN109190419A (en) * | 2018-09-03 | 2019-01-11 | 深圳福鸽科技有限公司 | Key encrypted circuit and method |
CN112200584A (en) * | 2020-11-05 | 2021-01-08 | 加减信息科技(深圳)有限公司 | Input circuit of payment acceptance terminal |
Also Published As
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CN102857232B (en) | 2016-03-09 |
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