CN203984397U - A kind of calibration circuit of new A DC key scanning circuit - Google Patents
A kind of calibration circuit of new A DC key scanning circuit Download PDFInfo
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- CN203984397U CN203984397U CN201420369976.1U CN201420369976U CN203984397U CN 203984397 U CN203984397 U CN 203984397U CN 201420369976 U CN201420369976 U CN 201420369976U CN 203984397 U CN203984397 U CN 203984397U
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Abstract
The utility model discloses a kind of calibration circuit of new A DC key scanning circuit, comprise electric resistance partial pressure unit, multiway analog switch unit and micro-control unit, described electric resistance partial pressure unit is joined end to end and forms at both ends of power successively by a plurality of resistance, the input of described multiway analog switch unit connects respectively the common port of each button and corresponding resistor, output connects the input of ADC, the input of described micro-control unit connects the output of ADC, and output is connected with the address end of described multiway analog switch unit respectively.The utility model can be calibrated preset value at any time according to the actual resistance accessing in current circuit, even if button has been used long period or key circuit to be oxidized, during calibration, reset preset value, realized the function of calibrating at any time key assignments, still can effectively detect key assignments, thereby guaranteed the accuracy of ADC recognition by pressing keys, the useful life of having improved system.
Description
Technical field
The utility model relates to a kind of ADC key scanning circuit, particularly a kind of calibration circuit of new A DC key scanning circuit.
Background technology
In actual life, the misoperation that often can run into independent button occurs.This type of key scan is mostly ADC key scan.ADC is analog to digital converter, and when having button to press, the resistance value being linked in circuit is different, thereby obtains different electric resistance partial pressure values.MCU identifies different buttons by the voltage of analog to digital converter Gather and input.In existing ADC (analog to digital converter) key scanning circuit, if service time is long, or in keyboard, entering dirt is oxidized, now divider resistance value can change, having changed resistance to earth value, can there is larger difference in the value that causes magnitude of voltage that ADC (analog to digital converter) collects and circuit to pre-set.Exceed preset range and be easy to cause the harassing of button, misoperation.This Time Controller cannot normally be worked, and has reduced normal service life, in this case, just has to change corresponding key circuit.In existing ADC (analog to digital converter) keyboard scanning circuit, do not add button calibration circuit, once service time is long, or key circuit is oxidized, and just causes whole control system normally to work.
Utility model content
For solving existing problem in above-mentioned prior art, the utility model provides a kind of calibration circuit of new A DC key scanning circuit, can effectively solve oxidized and the harassing and misoperation of producing of key circuit after long-time use.
The utility model adopts following technical scheme to realize: a kind of calibration circuit of new A DC key scanning circuit, comprise electric resistance partial pressure unit, multiway analog switch unit and micro-control unit, described electric resistance partial pressure unit is joined end to end and forms at both ends of power successively by a plurality of resistance, the input of described multiway analog switch unit connects respectively the common port of each button and corresponding resistor, the output of described multiway analog switch unit connects the input of ADC, the input of described micro-control unit connects the output of ADC, the output of described micro-control unit is connected with the address end of described multiway analog switch unit respectively.
Preferably, described resistance is 8, and resistance is 10k; Described multiway analog switch unit is CD4051.
Compare with present technology, the utlity model has following beneficial effect: the utility model can be calibrated preset value at any time according to the actual resistance accessing in current circuit, even if button has been used long period or key circuit to be oxidized, during calibration, reset preset value, realized the function of calibrating at any time key assignments, still can effectively detect key assignments, thereby guarantee the accuracy of ADC recognition by pressing keys, the useful life of having improved system.
Accompanying drawing explanation
Fig. 1 is the functional block diagram of the utility model embodiment;
Fig. 2 is the circuit theory diagrams of the utility model embodiment.
Embodiment
Below in conjunction with specific embodiment, the calibration circuit of a kind of new A DC key scanning circuit of the utility model is described in further detail.
As depicted in figs. 1 and 2, the utility model provides a kind of calibration circuit of new A DC key scanning circuit, can save the I/O resource of system, according to the number of the convenient expansion of functional requirement button, realize button precisely detects simultaneously, it comprises electric resistance partial pressure unit, multiway analog switch unit and micro-control unit, and resistance R 1～R8 that described electric resistance partial pressure unit is 10k by 8 resistances joins end to end and forms at both ends of power successively; Described multiway analog switch unit is CD4051, and its input connects respectively the common port of button S1～S7 and corresponding resistor, does calibration and uses, and the output of CD4051 connects the input of ADC; The input of described micro-control unit connects the output of ADC, carries out the collection of voltage, and the P00 of described micro-control unit, P01, P02 connect respectively A, B, the C input of CD4051, control different passages, realizes the calibration to different key.
When S1 presses, the voltage that is input to MCU is: V
cc* (R2+ ... R8)/(R1+ ... R8)=7/8*V
cc.When different buttons is pressed, can collect different magnitudes of voltage, be transferred to MCU to identify corresponding button.When system powers on, MCU can realize the calibration to whole buttons by controlling passage switch terminal A, B, the C of CD4051.When the number of keys of system needs is greater than 7, can adopts the cascade of two CD4051, thereby can realize 15 buttons of 4 I/O mouths expansions.While needing more buttons, can expand according to this.
MCU control unit can be realized the identification to different key, thus the difference in functionality of control system.After system powers on, the P00 of MCU, P01, P02 mouth, with Fixed Time Interval output from 000 to 111, to realize the initialization of calibration to 7 buttons, after having calibrated, are stored corresponding key assignments.Then close the passage 0 of CD4051 to passage 6, with passage 7, gather different key assignments separately.When building while pressing, MCU contrasts according to the magnitude of voltage collecting and the magnitude of voltage of calibrating before, by routine processes, can realize the accurate collection to key assignments in respective range.Even if key circuit is partially oxidized, resistance changes, and still can identify accurately different key assignments.
The foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; anyly be familiar with those skilled in the art in the technical scope that the utility model discloses, the variation that can expect easily or replacement, all should be encompassed in protection range of the present utility model in.Therefore, protection range of the present utility model should be as the criterion with the protection range that claim was defined.
Claims (2)
1. the calibration circuit of a new A DC key scanning circuit, it is characterized in that: comprise electric resistance partial pressure unit, multiway analog switch unit and micro-control unit, described electric resistance partial pressure unit is joined end to end and forms at both ends of power successively by a plurality of resistance, the input of described multiway analog switch unit connects respectively the common port of each button and corresponding resistor, the output of described multiway analog switch unit connects the input of ADC, the input of described micro-control unit connects the output of ADC, the output of described micro-control unit is connected with the address end of described multiway analog switch unit respectively.
2. the calibration circuit of new A DC key scanning circuit according to claim 1, is characterized in that: described resistance is 8, and resistance is 10k; Described multiway analog switch unit is CD4051.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420369976.1U CN203984397U (en) | 2014-07-04 | 2014-07-04 | A kind of calibration circuit of new A DC key scanning circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420369976.1U CN203984397U (en) | 2014-07-04 | 2014-07-04 | A kind of calibration circuit of new A DC key scanning circuit |
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| CN203984397U true CN203984397U (en) | 2014-12-03 |
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| CN201420369976.1U Expired - Fee Related CN203984397U (en) | 2014-07-04 | 2014-07-04 | A kind of calibration circuit of new A DC key scanning circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106683653A (en) * | 2017-02-28 | 2017-05-17 | 孝感量子机电科技有限公司 | Touch key signal multi-channel processing circuit for piezoelectric electret flexible film electronic organ and method thereof |
| US20170168588A1 (en) * | 2015-12-14 | 2017-06-15 | Ite Tech. Inc. | Electronic apparatus and method for detecting status of keys thereof |
| CN107579733A (en) * | 2017-08-15 | 2018-01-12 | 北京奇虎科技有限公司 | A kind of key circuit and key device |
| CN111338263A (en) * | 2020-03-23 | 2020-06-26 | 江铃汽车股份有限公司 | Low-cost key circuit with hardware logic |
| CN113612478A (en) * | 2021-07-22 | 2021-11-05 | 珠海海奇半导体有限公司 | ADC key circuit calibration method and system, storage medium and key circuit |
-
2014
- 2014-07-04 CN CN201420369976.1U patent/CN203984397U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20170168588A1 (en) * | 2015-12-14 | 2017-06-15 | Ite Tech. Inc. | Electronic apparatus and method for detecting status of keys thereof |
| US9684383B1 (en) * | 2015-12-14 | 2017-06-20 | Ite Tech. Inc. | Electronic apparatus and method for detecting status of keys thereof |
| CN106683653A (en) * | 2017-02-28 | 2017-05-17 | 孝感量子机电科技有限公司 | Touch key signal multi-channel processing circuit for piezoelectric electret flexible film electronic organ and method thereof |
| CN106683653B (en) * | 2017-02-28 | 2020-11-10 | 苏州创力波科技有限公司 | Touch key signal multi-channel processing circuit and method for piezoelectric electret flexible film electronic organ |
| CN107579733A (en) * | 2017-08-15 | 2018-01-12 | 北京奇虎科技有限公司 | A kind of key circuit and key device |
| CN111338263A (en) * | 2020-03-23 | 2020-06-26 | 江铃汽车股份有限公司 | Low-cost key circuit with hardware logic |
| CN113612478A (en) * | 2021-07-22 | 2021-11-05 | 珠海海奇半导体有限公司 | ADC key circuit calibration method and system, storage medium and key circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141203 Termination date: 20170704 |