CN102523002A - High-reliability keyboard scanning method - Google Patents
High-reliability keyboard scanning method Download PDFInfo
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- CN102523002A CN102523002A CN2011103719056A CN201110371905A CN102523002A CN 102523002 A CN102523002 A CN 102523002A CN 2011103719056 A CN2011103719056 A CN 2011103719056A CN 201110371905 A CN201110371905 A CN 201110371905A CN 102523002 A CN102523002 A CN 102523002A
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Abstract
The invention relates to a high-reliability keyboard scanning method, which is a new keyboard scanning technical method and is mainly used for driving keyboard input equipment of an embedded system related to weapon equipment in a severe environment. By adopting a series of effective technical means such as stepping scanning, digital filtering and integrating discrimination, the anti-interference capability and the anti-false triggering capability of the keyboard equipment are obviously improved. Besides, the functions that the key triggering time is settable, interference signals with specific frequency can be filtered and the like are realized and the keyboard equipment is enabled to have an anti-interference capability specially customized aiming at specific application environments. By adopting the technical scheme, the cost of hardware is not increased and the method has the characteristics of low cost, high efficiency and high reliability. Since the anti-interference capability and the anti-false triggering capability are remarkable and the compatibility is good, the method can meet the application demands of various weapon equipment systems in severe military environments.
Description
Technical field
The invention belongs to the keyboard scan technical field, particularly relate to the high reliability keyboard scanning method.
Background technology
The keyboard scan technology is the important technology method of embedded system device input.Current some keyboard scan technology commonly used or chip spininess are used the design in the civil area, and antijamming capability is very poor under adverse circumstances such as vibration, noise, and the false triggering phenomenon takes place often.
The keyboard scan technical method of conventional, the keyboard scan hardware circuit is formed a ranks matrix by plurality of keys, line by line (or by row) output scanning signal; Again by row (or line by line) read scanning result, when certain key is pressed, its pairing row and column is connected; The sweep signal of output is transfused to end and detects, because the mechanical elasticity effect of button, there be " shake " in the beginning and the ending of pressing at button; Traditional technology method goes dithering process through suitable delay, obtains key value.
Under the applied environment condition of severe, ambient noise may be coupled to the input of scan matrix, and violent vibrations also may make the instantaneous closure of button.These situation all can make input the disturbing pulse signal of certain pulsewidth occur, thereby when input detects sweep signal, may judge by accident certainly and press for keyboard, and give the key value that makes mistake.Address this problem, if the only simple time span that increases de-jitter delay can cause button ineffective, keyboard input devices is difficult to problems such as operation; And, keyboard scan equipment antijamming capability situation very poor, the button false triggering is taken place often if do not increase the length of de-jitter delay.Therefore, traditional this keyboard scan technical method is difficult to be applied in other environment of weaponry level.
Summary of the invention
The objective of the invention is to overcome the above-mentioned deficiency of prior art; The high reliability keyboard scanning method is provided; This scan method has improved the antijamming capability of matrix keyboard scanning technique, anti-false triggering ability through the technical scheme that adopts innovation; Possessing the button triggered time simultaneously can be provided with function, and uses down function such as filtering CF interference signal in specific environment, improves validity and reliability that keyboard equipment is imported.
Above-mentioned purpose of the present invention is achieved through following technical scheme:
The high reliability keyboard scanning method comprises the steps:
(1) keyboard is carried out classification scanning, concrete grammar is: establishing keyboard is that X is capable, the matrix keyboard of Y row, by the capable generation of X scanning sequence signal; Read scanning result from Y row, when the button that lists as the capable j of i is pressed, j row and i is capable is connected; J row input pin reads i line output pin scanning impulse, thereby obtains coordinate for (i, button j) press the pulse signal of process; I ∈ X wherein, j ∈ Y;
(2) scanning result to keyboard carries out digital filtering; Comprise that coordinate is that (i, button j) press moment and button unclamps the digital filtering of the shake pulse of moment generation, and concrete grammar is: button is pressed moment; The shake pulse appears; Do not make the filtering output switching activity for high, still with consistent before button is pressed, maintenance is output as low; Button unclamps moment, the shake pulse occurs, and it is low not making the filtering output switching activity, still presses in the process consistently with button, and maintenance is output as height;
(3) the filtered keyboard scan result of numeral is carried out the judgement of pulsewidth integration, concrete grammar is: using reference clock is that (i, key pulse width j) carry out integral counting to the filtered coordinate of numeral; And the key pulse width is provided with threshold value, if key pulse width gauge numerical value less than said threshold value, judges that then coordinate is (i; J) button is not pressed; If key pulse width gauge numerical value more than or equal to said threshold value, judges that then coordinate is that (i, button j) is pressed.
In above-mentioned high reliability keyboard scanning method; In the step (2) scanning result of keyboard is carried out digital filtering and comprise that also button presses the digital filtering of the false triggering pulse that produces in the process, concrete grammar is: button is pressed in the process, and the filtering input and output are height; When the false triggering pulse occurring; It is low not making the filtering output switching activity, and still to press process consistent with button, keeps being output as height.
In above-mentioned high reliability keyboard scanning method; In the step (2) to the scanning result of keyboard carry out digital filtering also comprise button press before, during and after the digital filtering of the disturbing pulse that occurs of whole process; Concrete grammar is: before button was pressed, filtering was input as low, when disturbing pulse occurring; Do not make the filtering upset for high, still keep being output as low; Button is pressed moment, disturbing pulse occurs, does not make the filtering output switching activity for high, keeps being output as low; Button is pressed in the process, and the filtering input and output are height, and when disturbing pulse occurring, it is low not making the filtering output switching activity, keeps being output as height; Button unclamps moment, disturbing pulse occurs, and it is low not making the filtering output switching activity, keeps being output as height; After button is totally released, when disturbing pulse occurring, do not make the filtering upset for high, input and output are low.
In above-mentioned high reliability keyboard scanning method; Digital filtering adopts the d type flip flop series connection of N rank to constitute the disturbing pulse digital filter realization of N rank in the step (2); When the value of d type flip flop is 1 a number during more than or equal to
, the output result is 1; When the value of d type flip flop is not that 1 number is during less than
; Do not overturn, the output result still is 1; When the value of d type flip flop is 0 a number during more than or equal to
, the output result is 0; When the value of d type flip flop is not that 0 number does not overturn less than
, the output result still is 0.
In above-mentioned high reliability keyboard scanning method; Adopt pulsewidth integration decision device to carry out the judgement of pulsewidth integration in the step (3), said pulsewidth integration decision device is made up of 32 digit counters and decision device, is input as reference clock, key pulse width and set decision threshold; Be output as correct key assignments; Counter carries out integral counting to the key pulse width, and drawing coordinate after decision device compares count value and set threshold value is (i, j) key assignments of button.
The present invention compared with prior art has following beneficial effect:
(1) keyboard scanning method of the present invention uses effective technology means such as classification scanning, digital filtering, integration judgement; Make keyboard equipment have very strong antijamming capability and anti-false triggering ability in adverse circumstances, in addition, but the present invention's filtering CF interference signal also; Thereby also be specially adapted under the specific application environment; The strong anti-interference ability that can customize especially significantly improves the reliability of keyboard equipment, is an efficient highly reliable keyboard scan technology that is applicable to the weaponry level applications;
(2) the more traditional keyboard scanning method of keyboard scanning method of the present invention can have been removed the shake pulse; Thereby strengthened the shake ability of going greatly; Digital filtering method among the present invention can effectively be removed the false triggering pulse in addition, thereby has strengthened anti-false triggering ability greatly;
(3) the digital filtering function in the keyboard scanning method of the present invention can effectively be removed disturbing pulse equally; Especially during the interference signal of special frequency; Can be through digital filter exponent number N be set; Realization is eliminated interference signal pointedly to the filtering of CF interference signal, therefore has very strong antijamming capability;
(4) the button triggered time can be provided with in the keyboard scanning method of the present invention, through the threshold value of button integration judgement is set, realizes the setting in button triggered time, thereby realizes more reliable recognition of button;
(5) keyboard scanning method of the present invention is on hardware, and any cost of not extra increase has with low cost; The high-efficiency reliable characteristics; Its significant antijamming capability and anti-false triggering ability, and favorable compatibility can satisfy various weaponry system in abominable military environmental applications demand.
Description of drawings
Fig. 1 is a matrix keyboard hardware circuit sketch map of the present invention;
Fig. 2 presses the digital filtering principle schematic of moment for button in the keyboard scanning method of the present invention;
Fig. 3 presses the digital filtering principle schematic in the process for button in the keyboard scanning method of the present invention;
Fig. 4 unclamps the digital filtering principle schematic of moment for button in the keyboard scanning method of the present invention;
Fig. 5 is button pulsewidth integration judgement principle schematic in the keyboard scanning method of the present invention.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:
Keyboard scanning method of the present invention is on the basis of conventional keyboard scan matrix hardware circuit; Through the digital filtering of error code pulse being handled and scanning result being carried out the integration judgement; Adopt digital filter to eliminate shake pulse, disturbing pulse and false triggering pulse; Eliminated the influence of disturbing pulse signal that environment causes, made the system can make effective judgement, provided correct key assignments the button testing result.
Digital filtering adopts the d type flip flop series connection of N rank to constitute N rank disturbing pulse digital filter and realizes; D type flip flop with the series connection of N level is an example; Only when the value of d type flip flop be 1 number during more than or equal to
, the output result is 1; When the value of d type flip flop is not that 1 number is during less than
; Keep original numeric state; Do not overturn, the output result still is 1; Only when the value of d type flip flop be 0 number during more than or equal to
, the output result is 0; When the value of d type flip flop is not that 0 number is held original numeric state less than
; Do not overturn, the output result still is 0.
Be illustrated in figure 1 as matrix keyboard hardware circuit sketch map of the present invention,,, read (input) scanning result from the Y row by the capable generation of X (output) scanning sequence signal for the capable Y column matrix of X keyboard (getting X=Y=4 in the accompanying drawing 1) with signal.When the button that lists as the capable j of i is pressed; J is listed as and i is capable is connected, and j row input pin reads i line output pin scanning impulse, is (i thereby obtain coordinate; J) button is pressed the process pulse signal; By digital filter filtering shake pulse, false triggering pulse, disturbing pulse, process button pulsewidth integration decision device output at last obtains coordinate and is (i, button value j) again.
Fig. 2, Fig. 3, shown in Figure 4; It is key method of the present invention; Be the principle process of N exponent number character filter filtering shake pulse, false triggering pulse and disturbing pulse: convenient, succinct for making explanation, accompanying drawing is that (i, j) button is pressed and is example description with filter order N=3, coordinate only.
The mechanical action of button or environmental interference make in the forward position of key scan pulse, back edge, the process to have shake pulse, false triggering pulse and the disturbing pulse signal much smaller than the key main body pulse duration.
Being illustrated in figure 2 as the digital filtering principle schematic before button in the keyboard scanning method of the present invention is pressed moment, is that (i is before button j) is pressed at coordinate; Being input as of digital filtering is low, is output as lowly, and button is pressed moment; Owing to reason machinery or environment; May produce shake pulse or disturbing pulse, because its pulsewidth is less than N/3 (wherein N is a filter order), so filter output is not overturn; Filtering output still remains low, thus shake or disturbing pulse before the filtering button is pressed.
Be illustrated in figure 3 as in the keyboard scanning method of the present invention button and press the digital filtering principle schematic in the process, at coordinate be (i, button j) are pressed in the process, digital filtering be input as height, be output as height.Button is pressed in the process; Owing to reason machinery or environment; May produce false triggering pulse or disturbing pulse, because its pulsewidth is less than N/3 (wherein N is a filter order), so filter output is not overturn; Filtering output still remains height, thereby the filtering button is pressed false triggering or disturbing pulse in the process.
Be illustrated in figure 4 as the digital filtering principle schematic that button in the keyboard scanning method of the present invention unclamps moment, at coordinate be (i, after button j) is released, digital filtering be input as height, be output as height.Button unclamps moment; Owing to reason machinery or environment; May produce shake pulse or disturbing pulse, because its pulsewidth is less than N/3 (wherein N is a filter order), so filter output is not overturn; Filtering output still remains height, thereby the filtering button is pressed false triggering or disturbing pulse in the process.
Key pulse has been eliminated the shake, false triggering, the interference isopulse signal that occur in the whole process of button well through behind the digital filtering.Through the integration decision threshold is set, can realize button the be provided with function in triggered time in addition, functions such as interference signal that can the filtering CF have significantly improved the input efficiency and the reliability of keyboard equipment.
Before wherein button was pressed, filtering was input as low, when disturbing pulse occurring, did not make filtering upset for high, still kept being output as low, omitted accompanying drawing here; After button is totally released, when shake pulse or disturbing pulse occurring, do not make the filtering upset for high, it is low that input and output are, and omits accompanying drawing here.
Be illustrated in figure 5 as button pulsewidth integration judgement principle schematic in the keyboard scanning method of the present invention, through the key pulse behind the digital filtering, by pulsewidth integration decision device output key value; Pulsewidth integration decision device adopts 32 digit counters and decision device to form, the digital integration judgement be input as reference clock, key pulse width and set decision threshold, be output as correct key assignments; Counter carries out integral counting to the key pulse width, and decision device compares count value and set threshold value, if count value is less than threshold value; Then think button (i; J) be not pressed, if count value, is then thought button (i more than or equal to threshold value; J) be pressed, and export the key assignments of being pressed.
The keyboard scan technology that the present invention is more traditional has the stronger shake ability of going: the mechanical action that button is pressed can produce shake pulse to a certain degree; In the conventional keyboard scanning technique method; Adopt the method for time delay to eliminate the shake pulse; But this method is not eliminated the shake pulse, just skips the detection of shake pulse through time delay.If time of delay is too short, does not reach and shake purpose; If time of delay is oversize, can make button ineffective again.The present invention then can remove the shake pulse, thereby has strengthened the shake ability of going greatly.
The keyboard scan technology that the present invention is more traditional has stronger anti-false triggering ability: the vibration of environment can cause the instantaneous closure of keyboard, produces the false triggering pulse.In conventional keyboard scanning technique method, do not have effective anti-vibration performance, and the digital filtering method among the present invention can effectively be removed the false triggering pulse, thereby strengthen anti-false triggering ability greatly.
The keyboard scan technology that the present invention is more traditional has stronger anti-environmental interference ability: when having stronger interference signal in the applied environment; Matrix keyboard output stronger disturbing pulse on may being coupled; Digital filtering function among the present invention can effectively be removed disturbing pulse equally, especially during the interference signal of special frequency, and can be through digital filter exponent number N be set; Eliminate interference signal pointedly, therefore have very strong antijamming capability.
The above; Be merely the best embodiment of the present invention, but protection scope of the present invention is not limited thereto, any technical staff who is familiar with the present technique field is in the technical scope that the present invention discloses; The variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.
The content of not doing to describe in detail in the specification of the present invention belongs to this area professional and technical personnel's known technology.
Claims (5)
1. the high reliability keyboard scanning method is characterized in that comprising the steps:
(1) keyboard is carried out classification scanning, concrete grammar is: establishing keyboard is that X is capable, the matrix keyboard of Y row, by the capable generation of X scanning sequence signal; Read scanning result from Y row, when the button that lists as the capable j of i is pressed, j row and i is capable is connected; J row input pin reads i line output pin scanning impulse, thereby obtains coordinate for (i, button j) press the pulse signal of process; I ∈ X wherein, j ∈ Y;
(2) scanning result to keyboard carries out digital filtering; Comprise that coordinate is that (i, button j) press moment and button unclamps the digital filtering of the shake pulse of moment generation, and concrete grammar is: button is pressed moment; The shake pulse appears; Do not make the filtering output switching activity for high, still with consistent before button is pressed, maintenance is output as low; Button unclamps moment, the shake pulse occurs, and it is low not making the filtering output switching activity, still presses in the process consistently with button, and maintenance is output as height;
(3) the filtered keyboard scan result of numeral is carried out the judgement of pulsewidth integration, concrete grammar is: using reference clock is that (i, key pulse width j) carry out integral counting to the filtered coordinate of numeral; And the key pulse width is provided with threshold value, if key pulse width gauge numerical value less than said threshold value, judges that then coordinate is (i; J) button is not pressed; If key pulse width gauge numerical value more than or equal to said threshold value, judges that then coordinate is that (i, button j) is pressed.
2. high reliability keyboard scanning method according to claim 1; It is characterized in that: in the said step (2) scanning result of keyboard is carried out digital filtering and comprise that also button presses the digital filtering of the false triggering pulse that produces in the process, concrete grammar is: button is pressed in the process, and the filtering input and output are height; When the false triggering pulse occurring; It is low not making the filtering output switching activity, and still to press process consistent with button, keeps being output as height.
3. high reliability keyboard scanning method according to claim 1 and 2; It is characterized in that: in the said step (2) to the scanning result of keyboard carry out digital filtering also comprise button press before, during and after the digital filtering of the disturbing pulse that occurs of whole process; Concrete grammar is: before button was pressed, filtering was input as low, when disturbing pulse occurring; Do not make the filtering upset for high, still keep being output as low; Button is pressed moment, disturbing pulse occurs, does not make the filtering output switching activity for high, keeps being output as low; Button is pressed in the process, and the filtering input and output are height, and when disturbing pulse occurring, it is low not making the filtering output switching activity, keeps being output as height; Button unclamps moment, disturbing pulse occurs, and it is low not making the filtering output switching activity, keeps being output as height; After button is totally released, when disturbing pulse occurring, do not make the filtering upset for high, input and output are low.
4. high reliability keyboard scanning method according to claim 1 and 2; It is characterized in that: digital filtering adopts the d type flip flop series connection of N rank to constitute the disturbing pulse digital filter realization of N rank in the said step (2); When the value of d type flip flop is 1 a number during more than or equal to
, the output result is 1; When the value of d type flip flop is not that 1 number is during less than
; Do not overturn, the output result still is 1; When the value of d type flip flop is 0 a number during more than or equal to
, the output result is 0; When the value of d type flip flop is not that 0 number does not overturn less than
, the output result still is 0.
5. high reliability keyboard scanning method according to claim 1; It is characterized in that: adopt pulsewidth integration decision device to carry out the judgement of pulsewidth integration in the said step (3); Said pulsewidth integration decision device is made up of 32 digit counters and decision device; Be input as reference clock, key pulse width and set decision threshold, be output as correct key assignments, counter carries out integral counting to the key pulse width; Drawing coordinate after decision device compares count value and set threshold value is (i, j) key assignments of button.
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Cited By (3)
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CN104199563A (en) * | 2014-09-23 | 2014-12-10 | 马根昌 | Electromagnetic keyboard |
CN105071816A (en) * | 2015-08-12 | 2015-11-18 | 长沙市博巨兴电子科技有限公司 | High-efficiency quick key scanning method |
CN107957790A (en) * | 2017-12-11 | 2018-04-24 | 广东虹勤通讯技术有限公司 | A kind of PC keyboards dynamic response control method, device, equipment and storage medium |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104199563A (en) * | 2014-09-23 | 2014-12-10 | 马根昌 | Electromagnetic keyboard |
CN104199563B (en) * | 2014-09-23 | 2017-03-22 | 陈浩宇 | Electromagnetic keyboard |
CN105071816A (en) * | 2015-08-12 | 2015-11-18 | 长沙市博巨兴电子科技有限公司 | High-efficiency quick key scanning method |
CN105071816B (en) * | 2015-08-12 | 2018-04-20 | 长沙市博巨兴电子科技有限公司 | A kind of high efficiency quick key scan method |
CN107957790A (en) * | 2017-12-11 | 2018-04-24 | 广东虹勤通讯技术有限公司 | A kind of PC keyboards dynamic response control method, device, equipment and storage medium |
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Application publication date: 20120627 |