CN103197531A - Adjustment method for automobile instrument panel electronic clock precision - Google Patents
Adjustment method for automobile instrument panel electronic clock precision Download PDFInfo
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- CN103197531A CN103197531A CN2013101293490A CN201310129349A CN103197531A CN 103197531 A CN103197531 A CN 103197531A CN 2013101293490 A CN2013101293490 A CN 2013101293490A CN 201310129349 A CN201310129349 A CN 201310129349A CN 103197531 A CN103197531 A CN 103197531A
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- automobile instrument
- electronic clock
- panel electronic
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Abstract
The invention relates to an adjustment method for automobile instrument panel electronic clock precision. By means of the method, the shortcomings that all clocks need to be tested repeatedly, time and labor are wasted, and volume production is difficult to achieve in an existing method are overcome. The method includes the steps that frequency data f1 of a crystal oscillator used by an automobile instrument panel electronic clock micro-control unit and frequency data f2 output to a clock circuit are sent to an external debugging device computer through a bus; the computer computes the frequency data f1 and the frequency data f2 to acquire a frequency error and a feedback control value; and the computer outputs the feedback control value through the bus, the automobile instrument panel electronic clock micro-control unit corrects reference time of the clock circuit and writes the frequency error into an erasable memorizer at the same time, and the automobile instrument panel electronic clock micro-control unit eliminates the frequency error from the frequency data 1 in the frequency data f2 output to the clock circuit in follow-up processes.
Description
Technical field
The invention belongs to the automobile instrument field, be specifically related to a kind of precision regulation method of automobile instrument electronic clock.
Background technology
The automobile instrument panel electronic clock is electronic equipment very practical and common on the automobile, but many electronic clock low precisions are arranged, and debug difficulties, influences user's normal use.It is a variety of to cause the inaccurate reason of automobile instrument panel electronic clock precision to have, comprising the error of the precision of the design of oscillatory circuit, used crystal, load capacitance, temperature, PCB printed circuit board traces etc. aspect.Automobile instrument panel mainly is that crystal oscillator determines with the precision of electronic clock.
Standard according to automobile industry, the error of instrument clock every day should be in ± 1 second, the error clock that error in 1 second equals per second multiply by the clock period, for example: because the time error that 20PPm and 1PPm crystal oscillator error cause, calculate 32.768KHz crystal oscillator and the error/second of 8.000MHz crystal oscillator in a second.Error is respectively 20PPm and 1PPm, 32.768KHz its error in one second of crystal oscillator 20PPm is=(20 * 32768/1000000) * 1/32.768=0.00002 second, 8.000MHz crystal oscillator 1PPm, its error in one second is=and (1 * 8000000/1000000) * 1/8000000=0.000001 second.
The method of adjusting the crystal oscillator oscillation error at present is to measure the error of crystal oscillator earlier, through calculating, finds the capacitor's capacity of proper fit, is equipped with the adjustment of capacitor's capacity again, makes it the crystal oscillator oscillation error that reaches desirable.Want to satisfy accuracy requirement, just must all want repeated test by every clock, this mode not only wastes time and energy, and is difficult to reach the efficient of batch process.
Or according to calculating, directly use crystal oscillator and the capacitor of choosing the appearance value.Used like this combination of devices error is easy to just exceed requirement.This also is the main cause of electronic clock low precision.
Summary of the invention
The purpose of this invention is to provide a kind of automobile instrument panel electronic clock precision regulation method, all want repeated test to solve existing every clock of method, waste time and energy, be difficult to reach the shortcoming of batch process.
Method of the present invention comprises the steps: one, by bus 2 the frequency data f2 that frequency data f1 and the automobile instrument panel electronic clock micro-control unit 1 of automobile instrument panel electronic clock micro-control unit 1 employed crystal oscillator 1-1 outputs to clock circuit 4 is sent in the external debug equipment computer 3; Two, 3 couples of frequency data f1 of external debug equipment computer and frequency data f2 calculate, and draw frequency error and feedback control value; Three, external debug equipment computer 3 outputs to feedback control value in the automobile instrument panel electronic clock micro-control unit 1 by bus 2, by the reference time of automobile instrument panel electronic clock micro-control unit 1 position circuit 4, simultaneously frequency error is write among the scratch pad memory 1-2 by automobile instrument panel electronic clock micro-control unit 1, in the follow-up frequency data f2 that outputs to clock circuit 4, from frequency data f1, eliminate frequency error by automobile instrument panel electronic clock micro-control unit 1.
The present invention links to each other external debug equipment computer 3 by bus with automobile instrument panel electronic clock MCU, measure and handle automatically the crystal oscillator oscillation error with outer computer according to the crystal oscillator of having installed and fixing capacitor's capacity, and utilize bus to be stored in the scratch pad memory automatically by automobile instrument panel electronic clock system MCU.So namely overcome the error that causes because of the components and parts precision, and be very beneficial for producing in batches.
Description of drawings
Fig. 1 be the inventive method based on electrical block diagram.
Embodiment
Embodiment one: specify present embodiment below in conjunction with Fig. 1.Present embodiment comprises the steps: one, by bus 2 the frequency data f2 that frequency data f1 and the automobile instrument panel electronic clock micro-control unit 1 of automobile instrument panel electronic clock micro-control unit 1 employed crystal oscillator 1-1 outputs to clock circuit 4 is sent in the external debug equipment computer 3; Two, 3 couples of frequency data f1 of external debug equipment computer and frequency data f2 calculate, and draw frequency error and feedback control value; Three, external debug equipment computer 3 outputs to feedback control value in the automobile instrument panel electronic clock micro-control unit 1 by bus 2, by the reference time of automobile instrument panel electronic clock micro-control unit 1 position circuit 4, simultaneously frequency error is write among the scratch pad memory 1-2 by automobile instrument panel electronic clock micro-control unit 1, in the follow-up frequency data f2 that outputs to clock circuit 4, from frequency data f1, eliminate frequency error by automobile instrument panel electronic clock micro-control unit 1.
Clock in the instrument of prior art normally adopts independent clock chip, links to each other with instrument MCU then, outputs in the LCD display of instrument again.And all be furnished with crystal oscillator among the instrument MCU, and can adopt the crystal oscillator of MCU autogamy to substitute crystal oscillator in the clock chip, namely use the function of software simulation clock chip, thereby the cancellation clock chip reduces cost.But the precision of the crystal oscillator of the MCU autogamy of instrument is subjected to condition restriction more, as the own error of matching capacitance, the discrete electric capacity that the printed board cabling produces etc., the most nearly 5-6pF of combination capacitor of its generation.Have a strong impact on the precision of crystal oscillator.
Present embodiment adopts specified frequency of the fixing output of the pin of MCU, because the frequency that MCU produces all is to have the crystal oscillator of MCU autogamy to determine, namely the deviation of this assigned frequency namely can be extrapolated the system deviation of the crystal-oscillator circuit of MCU autogamy, test the frequency of this MCU port again, can obtain impregnable MCU real crystal oscillator deviation.
Utilize another pin of MCU that this deviation data is stored in MCU simultaneously and carry in the scratch pad memory, by mode of braking, by bus the external debug equipment computer is linked to each other with automobile instrument panel electronic clock MCU again, read deviation data.Finally utilize outer computer according to deviation data, calculate and also to adjust instrument MCU internal data, make the crystal oscillator oscillation error reach the production request for utilization, and the data after will adjusting by communication bus write among the automobile instrument panel electronic clock Mcu of system.Overcome the error that causes because of the components and parts precision like this, be very beneficial for producing in batches
Oneself weighs widespread use on the vapour truck combination instrument in Jinan this kind method, and degree of accuracy increases, and has obtained the consistent favorable comment of producer.Robotization is handled, and does not need artificial detection, has saved the time greatly and has improved work efficiency.
Embodiment two: specify present embodiment below in conjunction with Fig. 1.Bus 2 adopts the cAN bus in the present embodiment.
Claims (2)
1. automobile instrument panel electronic clock precision regulation method is characterized in that it comprises the steps: one, by bus (2) the frequency data f2 that frequency data f1 and the automobile instrument panel electronic clock micro-control unit (1) of the employed crystal oscillator of automobile instrument panel electronic clock micro-control unit (1) (1-1) outputs to clock circuit (4) is sent in the external debug equipment computer (3); Two, external debug equipment computer (3) calculates frequency data f1 and frequency data f2, draws frequency error and feedback control value; Three, external debug equipment computer (3) outputs to feedback control value in the automobile instrument panel electronic clock micro-control unit (1) by bus (2), by the reference time of automobile instrument panel electronic clock micro-control unit (1) position circuit (4), simultaneously frequency error is write in the scratch pad memory (1-2) by automobile instrument panel electronic clock micro-control unit (1), in the follow-up frequency data f2 that outputs to clock circuit (4), from frequency data f1, eliminate frequency error by automobile instrument panel electronic clock micro-control unit (1).
2. automobile instrument panel electronic clock precision regulation method according to claim 1 is characterized in that bus (2) adopts the CAN bus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013101293490A CN103197531A (en) | 2013-04-15 | 2013-04-15 | Adjustment method for automobile instrument panel electronic clock precision |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013101293490A CN103197531A (en) | 2013-04-15 | 2013-04-15 | Adjustment method for automobile instrument panel electronic clock precision |
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| CN103197531A true CN103197531A (en) | 2013-07-10 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2013101293490A Pending CN103197531A (en) | 2013-04-15 | 2013-04-15 | Adjustment method for automobile instrument panel electronic clock precision |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106773617A (en) * | 2016-11-28 | 2017-05-31 | 北京汽车研究总院有限公司 | A kind of automobile |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4154053A (en) * | 1976-04-23 | 1979-05-15 | Ebauches S.A. | Electronic timepiece having an adjustable rate of division and method for its manufacture |
| EP0683443A2 (en) * | 1994-05-20 | 1995-11-22 | Nec Corporation | Time correction of an electronic clock |
| JPH09145866A (en) * | 1995-11-21 | 1997-06-06 | Sanyo Electric Co Ltd | Time setting device and electronic device |
| CN102822750A (en) * | 2010-03-26 | 2012-12-12 | 西铁城控股株式会社 | Atomic clock |
-
2013
- 2013-04-15 CN CN2013101293490A patent/CN103197531A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4154053A (en) * | 1976-04-23 | 1979-05-15 | Ebauches S.A. | Electronic timepiece having an adjustable rate of division and method for its manufacture |
| EP0683443A2 (en) * | 1994-05-20 | 1995-11-22 | Nec Corporation | Time correction of an electronic clock |
| CN1128873A (en) * | 1994-05-20 | 1996-08-14 | 日本电气株式会社 | Correcting time indication of electronic watch |
| JPH09145866A (en) * | 1995-11-21 | 1997-06-06 | Sanyo Electric Co Ltd | Time setting device and electronic device |
| CN102822750A (en) * | 2010-03-26 | 2012-12-12 | 西铁城控股株式会社 | Atomic clock |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106773617A (en) * | 2016-11-28 | 2017-05-31 | 北京汽车研究总院有限公司 | A kind of automobile |
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Application publication date: 20130710 |