KR20090081682A - Electron clock for vehicle enabling self correction and method of correcting the same - Google Patents

Abstract

An electronic watch for a vehicle and an automatic correction method thereof are provided to eliminate troublesomeness of installing an auxiliary capacitor through soldering and to perform accurate time error correction. An electronic watch for a vehicle includes a clock device, an RTC unit, a processor, a non-volatile memory, a communicating unit and a driver unit. The clock device(11) performs oscillation. The RTC unit(151) is connected to the clock device and receives an oscillation signal. The processor(153) is connected to receive an output signal of the RTC unit. The non-volatile memory(155) is connected to the processor and stores external set-up value having an error value and an error correction period for the RTC unit. The communicating unit(159) is connected so as to receive signals from the processor and also transmits and receives signals to/from an external measuring device. The driver unit(157) is connected to the processor and drives a display unit(13).

Description

Electromagnetic clock for vehicle enabling self correction and method of correcting the same}

The present invention relates to an electronic clock having a reference frequency oscillator, and more particularly to a vehicle electronic clock having an automatic correction function.

Compared to a general mechanical clock, an electronic clock capable of providing a more accurate time is widely used. Electronic clocks calculate and display time using the intrinsic oscillation frequency of crystals and other materials. The clock is not only used by an individual to possess it or stored in a living space, but is also installed and used in various living appliances.

In addition, as a basic form or part of an electronic clock, various electronic devices, such as a computer and a communication device, that require real-time information, calculate and output real-time to perform a task required by a user at a desired time point according to the real-time flow. RTC (RTC: Real Time Clock) is often installed in a control unit such as a microprocessor.

Installation of various electronic equipment is also common in vehicles, and a clock is also commonly used with an electronic clock in the form of an RTC.

In general, the RTC is connected to a clock device such as a crystal oscillator such as an oscillation frequency of 32.768Khz, 4.194304Mhz, or a ceramic oscillator to generate a clock signal. However, such a clock signal may generate an error of about 20 ppm in one cycle for various reasons. For example, the clock element generates an error by changing the oscillation frequency according to environmental factors such as temperature, humidity, and atmospheric pressure. In addition, an error occurs due to the characteristics of the clock element itself. Due to this error, the time displayed is gradually different from the exact time over time.

Therefore, in the conventional vehicle electronic clock, the error of the electronic clock is measured, and an auxiliary capacitor or load capacitor (cX) having a capacity corresponding to the error is added to the capacitor connected to the RTC inside the electronic clock, and eventually the whole connected to the RTC. The method of correcting the time error caused by the clock element by adjusting the capacitance of the capacitor was used.

However, this conventional method has been very cumbersome since it consists of selecting an auxiliary capacitor with an appropriate capacity according to the measured error, installing it at the corresponding position on the circuit board attached to the electronic clock, and soldering it. Furthermore, since the auxiliary capacitor cannot produce the proper capacity every day, the auxiliary capacitor of some capacity is prepared and prepared in advance, and the capacitor of the corresponding capacity that is closest to the measured error is used so that there is some inaccuracy even after correction. do.

The present invention is to solve the problems of the conventional electronic clock correction method for a vehicle, eliminating the hassle of installing an auxiliary capacitor by soldering, and can correct the vehicle electronic clock can be more accurate time error correction than the conventional A method and an electronic clock for a vehicle are provided.

Vehicle electronic clock of the present invention for achieving the above object is

Clock setting element, display unit, an RTC unit connected to the clock element, a processor connected to the RTC unit, an external setting value connected to the processor and including an error value and an error correction period of the RTC by an input unit. It comprises a non-volatile memory for storing, a communication unit connected to the processor and connected to an external device for transmitting and receiving information and signals, a driver unit connected to the processor and driving the display unit.

In the vehicle electronic clock of the present invention, the RTC unit, the processor, the nonvolatile memory, the signal conversion circuit unit, and the driver unit may be formed of a single semiconductor chip to form a microcontrol unit (MCU). May be connected to an external input device including a power supply, the clock element, the display unit, an input device of the electronic clock itself, or an external measurement device for RTC through its own terminal.

In the present invention, an external measurement device among the external devices may process (measure) the output signal of the RTC received through the communication unit and directly input the measurement result to the MCU to store the measurement result in the nonvolatile memory. It can also be a device, such as a computer device. In this case, the communication unit of the computer device and the communication unit of the electronic clock may be connected through a tangible communication line so as to transmit and receive information with each other, or may be connected through a wireless communication means such as infrared communication.

In the present invention, an easy-to-write EEPROM may be used as the nonvolatile memory.

In addition, the vehicle electronic clock correction method for achieving the above object, in the vehicle electronic clock of the present invention, the step of setting the correction period of the electronic clock in the built-in program, the RTC signal through the communication unit measuring unit of the external computer device Measuring a time error of the RTC per correction period by transferring the signal, and transmitting the measured error value to the MCU through a communication unit of the electronic clock and inputting the same to a memory device (non-volatile memory); And correcting the time automatically by reflecting the measured error value input to the volatile memory.

In this case, the measuring of the visual error and the inputting of the measured error value into the nonvolatile memory may be automatically performed according to a program in one external device such as a computer that combines a measuring device and an input device.

According to the present invention, in the test process after manufacture of a vehicle electronic clock (also referred to as a calibration process in a manufacturing process), a time measurement caused by a clock element is accurately confirmed through an external measuring and input device, and the exact numerical value is determined by a program. Alternatively, the electronic clock can be automatically modified at regular intervals by storing it in nonvolatile memory as an input from an external device. Therefore, due to a cumulative error over a long period of time, the display time of the vehicle electronic clock causes a large difference from the standard time, and it is possible to eliminate the inconvenience of the user manually correcting the clock in order to correct it.

In addition, the process can be shortened by eliminating the trouble of installing the auxiliary capacitor as in the related art. Particularly, when electronically writeable non-volatile memory such as EEPROM is used as one-chip with RTC, processor, communication circuit and driver of electronic clock, component composition can be simplified, and it can be restarted after power supply to electronic clock is cut off. Even when supplied, the preset value can be stored to reflect the measured error value during the operation.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a block diagram showing a schematic configuration of a vehicle electronic clock according to an embodiment of the present invention.

Similar to the conventional vehicle electronic clock, in the present embodiment, the clock element 11 including the display unit 13 and the crystal oscillator, and the microcontrol unit 15 connected to the display unit 13 and the clock element 11 are provided. Equipped. However, the MCU 15 includes the RTC 151, the driver 157, and the processor 153 together with the EEPROM as the communication unit 159 for connecting to an external computer and the nonvolatile memory 155. The elements constituting these MCUs may be formed of one semiconductor chip according to the development of semiconductor devices, and may be used by forming one semiconductor chip or a plurality of chips in one package. Therefore, the MCU 15 usually has a plurality of connection terminals in the package configuring the same. Here, the clock element 11 is separate from the RTC 151, but the clock element 11 can be considered as an element in the RTC 151.

In addition to the communication unit for connecting to the outside, the electronic watch 10 may also be provided with an internal connection unit (not shown) for connecting the MCU to the electronic clock internal device around the MCU.

The RTC 151 is connected to the clock element 11 and internally processes the oscillation frequency of the clock element 11 to generate a pulse signal of, for example, 1 Hz or 1024 Hz, and receives the output of the division circuit in advance. It may be provided with a counting circuit for performing calculation in accordance with a calculation program and converting it into a signal representing a time.

2 is a configuration diagram showing an example of the configuration of the RTC. When the frequency signal of the crystal oscillator clock element 11 is input to the counter 41 of the RTC, the counter 41 counts each frequency, and the number counted by the counter 41 for one second as a unit time is previously registered in the first register. It compares with the frequency corresponding to 1 second input into (51), that is, the oscillation frequency. The comparison may be through the first comparator 43. If the number of frequencies counted by the counter 41 and the oscillation frequency coincide, the first comparator 43 outputs a signal. The output signal of the first comparator 43 becomes a time counting signal for the counting circuit 45 to change the time, and is fed back to the counter 41 to reset the count of the counter 41. The oscillation frequency, which is an input value of the first register 51, is an ideal oscillation frequency input by the processor 50 connected to the RTC to the EEPROM 60 initially through the input device 70 when the electronic clock is powered and operated. The value can be written by passing it to the processor's own register or the register 51 of the RTC section.

The output signal passing through the counting circuit 45 of the RTC is input to the processor 50, and the processor 50 relays the output signal to the driver as it is or converts it into a state suitable for the driver and transmits it. For example, the processor 50 has a second comparator (not shown) and second, third, and fourth registers (not shown) similarly to the RTC, and a modification period, for example, one hour, is input to the second register. The time at which the previous revision was made (eg 13:00) is recorded. If the conventional correction time (13 o'clock) differs from the current time (14:00) by one hour, the current time (14:00) is recorded in the third register and the current time is previously written in the fourth register. The time error (correction period) is added to or decremented by the deceleration circuit unit.

At this time, the time error value per hour of the fourth register is a result of accurate measurement by an external computer including a precision measuring instrument in advance, and is automatically recorded by the execution program in a predetermined storage location of the EEPROM through the communication unit and the processor of the electronic clock. Value.

Referring again to FIG. 1, the external computer 20 may include a communication unit (not shown) connected to the communication unit 159 of the electronic watch 10, for example, when the communication unit 159 of the electronic watch follows a serial communication scheme. The electronic watch 10 is connected to a communication line through one serial port. The precision frequency measurement program of the external computer 20 is executed, and the frequency signal of the RTC input from the electronic clock through the communication unit 159 of the serial communication method of the electronic clock, for example, the frequency division circuit of the RTC in the crystal oscillator clock element 11. And it receives the frequency signal passed through the processor and measures the exact frequency. The measured value is displayed on the display device of the external computer 20 and transmitted to the processor 153 of the electronic clock by reversely following the same communication path by a program in the external computer 20 without a separate input device such as a keyboard. The processor 153 of the electronic clock stores the value of the corresponding code input from the external computer 20 through serial communication in the corresponding memory address of the EEPROM. The external computer may signal the processor 153 through the communication unit 159 of the electronic clock to retrieve the error value stored in the corresponding address of the EEPROM.

Each communication unit may have a signal conversion unit for converting an input or output signal, but a simple signal transmission and reception may not be provided with a separate signal conversion unit, and simply connects with some terminals of the MCU 15. It may be made of a connector.

Although the present embodiment has a case of having a tangible signal line, wireless communication such as wireless communication through an infrared port may be used. In addition, it is assumed that there is no separate manual input, but it is also possible for the operator to input an error value by using an input device such as a keyboard of the external computer 20 itself.

It is assumed that the processor has a second comparator, second, third, and four registers and a deceleration circuit, but these portions may be installed together with a counting circuit in the RTC.

The driver 157 of FIG. 1 serves as a bit map or segment converter, for example, and transmits a signal of the processor 153 to the display unit 13 so that time display is performed. The driver 157 may also be included in the separate part without being included in the MCU 15.

The display unit 13 may use various types of display panels. For example, a display form using an LCD, an EL, or an LED element may be used.

In the vehicle electronic clock 10 having such a configuration, the time error value caused by the clock element itself can be accurately measured at an accuracy of, for example, 0.01 seconds per hour, in an ordinary range by an external measuring device. It is possible to simply input into the EEPROM, which is a nonvolatile memory 155 configured inside the MCU 15 through the terminal of. Therefore, if the time is automatically and periodically corrected using the input values through the configuration and operation described above, the electronic clock can indicate the correct time without the user manually manipulating a long period of time.

Next, looking at the present invention in terms of a method for correcting the time error value in the vehicle electronic clock of the present invention, in the state of manufacturing and completing the vehicle electronic clock 10 of the present invention, first, built in the storage device of the electronic clock Input the initial setting value including the electronic clock calibration cycle and initial time. The time error value per correction period is initially set to an arbitrary value such as zero. Typically, the initial set value input is performed almost simultaneously with the step of connecting the power supply to the electronic clock to start the electronic clock. Alternatively, the initial setting value may not be separately input in the initial driving step, and may be assumed to be input together with the time error value after the time error value mentioned in the following part is measured after being arbitrarily designated.

In an electronic clock in which power is connected, setting is performed, and a time display is activated, the processor transmits a signal of the RTC 151 to an external computer through a communication unit in the form of a serial port. The signal transmitted from the communication unit is input through the communication line and the serial port of the external computer. The frequency signal precision measurement section in the external computer compares this frequency signal with its more accurate frequency signal. This measures the time error of the RTC 151 per unit time or per arbitrarily determined calibration period. Depending on the terminal configuration of the MCU 15, the signal of the RTC 151 may be input to the external measurement equipment 20 through the direct communication unit, but in this embodiment is transmitted to the communication unit of the MCU through the processor 153, the external computer It is to be input to the measuring unit of. The measurement unit detects the difference between the actual oscillation frequency and the nominal oscillation frequency of the electronic clock and calculates the time error value per correction period.

In an electronic clock using a crystal oscillation element (crystal), when a crystal with an oscillation frequency of 4.194304 MHz is used, it is reduced to 1 Hz after 22 divisions, which can be regarded as 1 second. In fact, most of the fundamental frequency (4.194304MHz) is divided into 12 times to come out 1024Hz and output it to the outside to measure the error by measuring with an external computer 20 with a precise measuring unit. For example, if the calibration cycle is one day, when the signal output through the clock communication unit's MCU is measured by the external computer's measurement unit, and it reaches 1024.00759 Hz, the output value is multiplied by one day second, divided by 1024, and then subtracted one day second. +0.63 will be displayed, and this value is expressed in seconds per day. This value becomes the time error value per correction period and the correction is performed with this value.

The error value may be inputted into the EEPROM of the electronic clock MCU 15 through communication without an additional input means, and the operator may check the error value through a manual mode of the program. It can also be entered into the EEPROM of the electronic clock by inputting. At the same time as the input, the error value stored in the corresponding address of the EEPROM may be displayed on the display device of the external computer to check whether the data is correctly stored.

The processor 153 may retrieve the time error value per correction period from the corresponding address of the EEPROM for each correction period and use it for calculation. However, when setting once, the processor 153 stores the error value in a register in the processor 153 and continues to use it. to be. In this case, it may be necessary to set the clock again to replace the initial set error value currently recorded in the processor's register. This setting may be naturally performed by powering off the electronic clock at the factory, packaging, transporting, and delivering it, and then re-powering and setting the electronic clock again.

That is, if the error value is actually measured and recorded at the corresponding address in the EEPROM, the electronic clock can be packaged, shipped and delivered with the power off. Since the initial set value and the time error value per correction period are all stored in the EEPROM, which is the nonvolatile memory 155, the initial set value and the time error value per correction period may be maintained. When the power (not shown) is applied again, the processor 153 of the MCU 15 performs the initial setting value and the measured and recorded error value of the MCU by the initial process that is automatically executed before or after the setting operation to set the correct time. The time is recorded in the corresponding register in the display section 13 and displayed on the display unit 13.

In the normal clock driving state, the time is automatically corrected by reflecting the measured error value input to the nonvolatile memory 155 according to the correction period already input.

In addition, since the configuration and operation of a conventional electronic clock are well known, a description thereof will be omitted.

Although the present invention has been described through the above limited embodiments, it is obvious that the present invention may be implemented in various forms without changing the gist of the present invention.

1 is a block diagram showing a schematic configuration of a vehicle electronic clock according to an embodiment of the present invention.

2 is a configuration diagram showing an example of the configuration of the RTC in the vehicular electronic clock of the present invention.

Claims (5)

Clock element responsible for oscillation, a display unit, an RTC unit connected to the clock element to receive an oscillation signal, a processor connected to receive the generated signal of the RTC unit, an error value and an error of the RTC connected to the processor and by an external input means Non-volatile memory for storing an external setting value including a correction period, a communication unit connected to receive a signal from the processor, the communication unit is installed to enable transmission and reception of signals with an external measurement device, the display unit is connected to the processor to drive the display unit An on-vehicle electronic clock comprising a driver section for displaying time on the display. The method of claim 1, The RTC unit, the processor, the non-volatile memory, the communication unit, the driver unit is made of one package containing one semiconductor chip, or a plurality of semiconductor chips connected to each other built in one package Car electronic clock. The method of claim 1, The external measuring device is an external computer having a measuring unit, And the communication unit is connected to the external computer via serial communication so that the error value, which is the result of the measurement unit, can be directly stored in the nonvolatile memory through the external computer. The method of claim 1, And the nonvolatile memory is an EEPROM. In the method of time correction of the electronic clock for a vehicle according to claim 1, Setting a clock correction period in a program embedded in the electronic clock, Measuring a time error value per correction period by inputting a signal of the RTC to an external measuring device; Inputting the measured time error value to the nonvolatile memory using an input device; And correcting a time by reflecting the measured error value input to the nonvolatile memory according to the correction period. The external measuring device is an external computer that is integrally formed with the input device, and the measuring and inputting of the visual error value are automatically performed without a separate operator's work by a program of the external computer. The time correction method of the electronic clock for a vehicle to say.

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