JP2007328404A - Control method of real time clock device, and real time clock device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a real time clock device operating at low voltage and low current, and its control method. <P>SOLUTION: The real time clock device 10 comprises an oscillating circuit 14 for outputting source oscillation, a nonvolatile memory 18 that stores real time data and selectively receives current, a volatile memory 20 for receiving the real time data from the nonvolatile memory 18 and holding it, and a real time clock circuit 16 for performing clocking using the source oscillation input from the oscillating circuit 14 and the real time data stored in the volatile memory 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for controlling a real-time clock device and a real-time clock device.

Some real-time clock devices include an oscillation circuit provided with a piezoelectric vibrator, a real-time clock circuit that uses a source oscillation input from the oscillation circuit, and a memory in which data is written. This memory may be a memory (EEPROM) that can electrically rewrite data (Patent Document 1) or a memory (RAM) that electrically reads and writes data (Patent Document 2).
JP 2001-31786 A Japanese Patent Laid-Open No. Sho 62-145413

  The above-described real-time clock device is mounted on various electronic devices such as telephones and facsimiles. Some electronic devices shift from a normal use state to a low power consumption state (power saving mode) when the user is not using them in order to reduce power consumption. The real-time clock device installed in such an electronic device goes from the normal use state to the backup state as the electronic device shifts to the power saving mode, etc., and only the time is measured by the real-time clock circuit, and other operations are stopped. I am letting.

  By the way, the above-described EEPROM consumes a large amount of current even when writing / reading data or in a backup state. As a specific example, when comparing the current consumption at the time of data writing / reading in the EEPROM with the current consumption (backup current) in the backup state in the real-time clock circuit, the EEPROM has about 500 to 1000 times of the real-time clock circuit. Consumes twice as much current. Further, when the consumption current in the backup state in the EEPROM is compared with the backup current of the real-time clock circuit, the EEPROM consumes about twice the current of the real-time clock circuit. For this reason, the real-time clock device provided with the EEPROM consumes more current. When the power supply of an electronic device equipped with a real-time clock device is a battery, or when a real-time clock device in a backup state is driven by a battery, the battery is consumed quickly, and thus the product of the electronic device. Life may be shortened.

  The access speed of the EEPROM varies depending on the supplied voltage. That is, the EEPROM requires a high voltage in order to ensure a high access speed of about 400 Hz. In addition, the EEPROM requires a voltage comparable to the operating voltage of the real-time clock circuit at a slow access speed of about 40 Hz. However, when the real-time clock device is in a backup state, a high voltage for increasing the access speed to the EEPROM cannot be secured. That is, when the real-time clock device is in the backup state, the access speed to the EEPROM cannot be increased. When the access speed to the EEPROM is lowered, the operation time of the EEPROM becomes longer, and the current consumption increases accordingly.

The EEPROM has a limited number of rewrites. The number of rewrites is about 10 ⁴ to 10 ⁵ times. If the EEPROM data is frequently rewritten, for example, if the product life of the real-time clock device is set to 10 years, the upper limit of the number of times that the EEPROM can be rewritten will reach the upper limit of the product life, and rewriting is possible. It will disappear. Moreover, if the EEPROM is accessed frequently, the current consumption increases. Therefore, if the EEPROM is frequently rewritten, the product life of the real-time clock device is shortened, and further, the product life of an electronic device equipped with the real-time clock device is also shortened.

  In Patent Document 1, only data used for the real-time clock device is written in the EEPROM, and data writing is not open to the user. That is, the user of the real-time clock device cannot write data (user data) used by the user to the EEPROM. In the real-time clock device provided with the RAM of Patent Document 2, when the power supply is stopped, the data stored in the RAM is erased. For this reason, even if the user writes user data in the RAM, the user data is erased.

  An object of the present invention is to provide a real-time clock device that operates at a low voltage and a low current, and to provide a control method therefor.

The control method of the real-time clock device according to the present invention transfers the real-time data stored in the nonvolatile memory to the volatile memory when the initial power is turned on, and supplies current to the nonvolatile memory when the transfer of the real-time data is completed. The real-time clock circuit uses the real-time data transferred to the volatile memory and the source oscillation input from the oscillation circuit. The nonvolatile memory operates by selectively supplying current only when the initial power is turned on. Therefore, current consumption of the real-time clock device can be reduced, and voltage consumption can also be reduced. And the update of the real-time data caused by the timekeeping rewrites the real-time data stored in the volatile memory. Therefore, the real-time clock device can operate at a low voltage and a low current. Moreover, it is possible to prevent the real-time data stored in the nonvolatile memory from being frequently rewritten. And it can prevent that the product life of the electronic device in which the real-time clock device according to the present invention is mounted is shortened.

  Further, the control method of the real-time clock device according to the present invention stores the real-time data update generated by the time measurement in the real-time clock circuit in the volatile memory, generates a timing signal, and is nonvolatile when the main voltage is supplied. The current supply to the non-volatile memory is resumed, the updated real-time data is transferred from the volatile memory to the non-volatile memory, and the real-time data stored in the non-volatile memory is rewritten.

  The nonvolatile memory operates by selectively supplying a current when the stored real-time data is rewritten. Therefore, the real-time clock device can operate at a low voltage and a low current. When rewriting real-time data, the main voltage is supplied to the real-time clock device. For this reason, the access speed to the nonvolatile memory can be increased. Therefore, since rewriting is completed in a short time, the current consumption of the real-time clock device can be reduced and the voltage consumption can also be reduced. Furthermore, rewriting of real-time data stored in the non-volatile memory is performed when the real-time data stored in the volatile memory is updated, when a timing signal is generated, and when the main voltage is supplied. Is called. When these conditions are not met, the real-time data stored in the volatile memory is rewritten. For this reason, the number of rewrites of the nonvolatile memory can be reduced. And it can prevent that the product life of the electronic device in which the real-time clock device according to the present invention is mounted is shortened.

  The nonvolatile memory described above is characterized in that it stores real-time data and identification information used by a system (real-time clock device) such as a real-time clock circuit and user data used by a user. As a result, it is not necessary to provide a means for storing user data in the electronic device on which the real-time clock device is mounted, so that the circuit configuration of the electronic device can be simplified and miniaturized. In recent years, there has been a demand for miniaturization of electronic equipment, and electronic equipment equipped with the real-time clock device according to the present invention can meet this demand.

  The control method of the real-time clock device according to the present invention is characterized in that a reset signal is output to the outside when the transfer of real-time data from the nonvolatile memory to the volatile memory is completed. As a result, the real-time clock device can have the same function as the reset integrated circuit with a delay. Therefore, the number of parts of the entire electronic device on which the real-time clock device is mounted can be reduced, and the cost of the electronic device can be reduced.

  The real-time clock device according to the present invention stores an oscillation circuit that outputs a source oscillation, a non-volatile memory that stores real-time data, selectively supplied with current, and inputs and stores real-time data from the non-volatile memory. It is characterized by comprising a volatile memory, and a real-time clock circuit for measuring time using source oscillation input from an oscillation circuit and real-time data held in the volatile memory.

  The nonvolatile memory operates by selectively supplying current only when the initial power is turned on and when the stored real-time data is rewritten. For this reason, current consumption of the real-time clock device can be reduced, and voltage consumption can also be reduced. When rewriting real-time data, the main voltage is supplied to the real-time clock device. For this reason, the access speed to the nonvolatile memory can be increased, and rewriting is completed in a short time. From the above, the current consumption of the real-time clock device can be reduced and the voltage consumption can also be reduced.

  Furthermore, rewriting of real-time data stored in the non-volatile memory is performed when the real-time data stored in the volatile memory is updated, when a timing signal is generated, and when the main voltage is supplied. Is called. On the other hand, when these conditions are not met, the real-time data stored in the volatile memory is rewritten. For this reason, the number of rewrites of the nonvolatile memory can be reduced. If a real-time clock device having such characteristics is mounted on an electronic device, the product life of the electronic device can be prevented from being shortened.

  The real-time clock device according to the present invention includes an oscillation circuit that outputs a source oscillation, a non-volatile memory that stores real-time data, and real-time data that is input and stored from the non-volatile memory, and real-time data that is updated by timing , A real-time clock circuit for measuring time using source oscillation input from the oscillation circuit and real-time data stored in the volatile memory, and a control unit.

  The control unit described above is characterized by detecting the initial power-on, selectively supplying current to the nonvolatile memory, and performing real-time data transfer control from the nonvolatile memory to the volatile memory. In addition, the control unit detects the update of the real-time data stored in the volatile memory, the timing signal generated by the real-time clock circuit, and the turn-on of the main power supply, and selectively supplies the current to the nonvolatile memory. It is characterized by performing transfer control of updated real-time data to a nonvolatile memory.

  The timing for supplying current to the nonvolatile memory is when real-time data is transferred to the volatile memory or when updated real-time data is transferred from the volatile memory. When the real-time clock circuit measures time, no current is supplied to the nonvolatile memory. For this reason, current consumption of the real-time clock device can be reduced, and voltage consumption can also be reduced. When the updated real-time data is transferred to the nonvolatile memory, the main voltage is supplied to the real-time clock device. For this reason, the access speed to the nonvolatile memory can be increased, and data rewriting is completed in a short time. Therefore, current consumption of the real-time clock device can be reduced, and voltage consumption can be reduced. Furthermore, since the real-time data stored in the nonvolatile memory is rewritten when certain conditions are met, the number of times of rewriting the nonvolatile memory can be reduced. If a real-time clock device having such characteristics is mounted on an electronic device, the product life of the electronic device can be prevented from being shortened.

  Further, the above-described nonvolatile memory includes a storage unit (system region) for real-time data and identification information, and a storage unit (user region) for user data input from the outside. As a result, it is not necessary to provide a means for storing user data in the electronic device on which the real-time clock device is mounted, so that the circuit configuration of the electronic device can be simplified and miniaturized.

  In addition, the real-time clock device according to the present invention includes detection means for detecting completion of transfer of real-time data from the nonvolatile memory to the volatile memory, and reset signal output means for obtaining a signal from the detection means and outputting a reset signal. It is characterized by having. As a result, the real-time clock device can have the same function as the reset integrated circuit with a delay. Therefore, the number of parts of the entire electronic device on which the real-time clock device is mounted can be reduced, and the cost of the electronic device can be reduced.

  The best mode for controlling a real-time clock device and the real-time clock device according to the present invention will be described below. First, the first embodiment will be described. FIG. 1 is a block diagram of a real-time clock device according to the first embodiment. The real-time clock device 10 according to the first embodiment includes an oscillation circuit 14 including a piezoelectric vibrator 12, a real-time clock circuit 16, a nonvolatile memory 18, a volatile memory 20, a control unit 22, a voltage comparator 24, and a power-on A reset circuit 26 is provided.

  The non-volatile memory 18 stores real-time data used for timing by the real-time clock circuit 16. The nonvolatile memory 18 only needs to be capable of electrically rewriting stored data. As a specific example, the nonvolatile memory 18 may be an EEPROM, a flash memory, or the like. The volatile memory 20 may be a buffer memory (RAM) that can electrically read and write data.

  The piezoelectric vibrator 12 only needs to oscillate at a constant frequency, for example, 32.768 kHz, when an electric signal is supplied. The oscillation circuit 14 supplies an electric signal to the piezoelectric vibrator 12 and outputs a signal (source vibration) corresponding to the frequency oscillated by the piezoelectric vibrator 12. The real time clock circuit 16 is connected to the subsequent stage of the oscillation circuit 14. The real-time clock circuit 16 measures time based on the source oscillation input from the oscillation circuit 14 and the real-time data stored in the volatile memory 20.

  The control unit 22 controls the real-time clock circuit 16, the nonvolatile memory 18, and the volatile memory 20. And the control part 22 connects with the arithmetic processing part of an electronic device, when the real-time clock apparatus 10 is mounted in an electronic device. The arithmetic processing unit is mounted on the electronic device and controls the electronic device.

  The voltage comparator 24 is connected to the power supply voltage terminal VDD. The voltage comparator 24 compares power supply voltage values supplied via the power supply voltage terminal VDD and outputs a comparison result to the control unit 22. That is, the voltage comparator 24 determines whether the voltage supplied to the real-time clock device 10 is a main voltage or a backup voltage. The power-on reset circuit 26 is provided for resetting the real-time clock device 10 when the initial power is turned on. The control unit 22 is connected to the subsequent stage of the power-on reset circuit 26.

  The control method of the real-time clock device 10 having such a configuration is as follows. First, when an initial power supply (main voltage) is supplied to the real-time clock device 10 via the power supply voltage terminal VDD, the power-on reset circuit 26 detects this initial power-on and outputs the detection result to the control unit 22. When the detection result is input, the control unit 22 performs initial setting (reset) of the internal system of the real-time clock device 10, that is, the real-time clock circuit 16.

  Thereafter, the real-time data stored in the nonvolatile memory 18 is transferred to the volatile memory 20 under the control of the control unit 22. Real-time data is stored in the volatile memory 20 by this transfer. When the transfer of the real-time data is completed, the control unit 22 stops supplying current to the nonvolatile memory 18.

  Thereafter, the real-time clock device 10 uses the oscillation circuit 14 including the piezoelectric vibrator 12, the real-time clock circuit 16, and the volatile memory 20 to measure time. That is, the oscillation circuit 14 oscillates the piezoelectric vibrator 12 and the real time clock circuit 16 uses the source oscillation obtained by this oscillation. The real-time clock circuit 16 accesses the volatile memory 20 and uses real-time data stored therein. The real time clock circuit 16 does not access the nonvolatile memory 18. Therefore, the real-time clock device 10 uses a volatile memory 20 that consumes less power than the non-volatile memory 18, and thus operates at a low voltage and a low current.

  When the real-time clock circuit 16 updates the real-time data during the time measurement, the real-time data stored in the volatile memory 20 is rewritten. FIG. 2 is an explanatory diagram of a data block of the volatile memory. The volatile memory 20 stores real-time data for each block of the nonvolatile memory 18. That is, the volatile memory 20 is divided into blocks of a nonvolatile memory buffer 0, a nonvolatile memory buffer 1,... A nonvolatile memory buffer n. Real-time data rewriting is performed for each updated block, and a data update flag corresponding to this block is set. As an example, when real-time data in the nonvolatile memory buffer 0 is updated, the real-time data in the nonvolatile memory buffer 0 is rewritten, and a data update flag (1) indicating that the data in this block has been updated is set. .

  When the electronic device equipped with the real time clock device 10 shifts from the normal operation state to the power saving mode, the real time clock device 10 is changed from the normal operation state to the backup state. In this case, the power supply voltage supplied to the real-time clock device 10 via the power supply voltage terminal VDD changes from the main voltage to the backup voltage, and the voltage value decreases. At this time, the real-time clock device 10 operates only the oscillation circuit 14 including the piezoelectric vibrator 12, the real-time clock circuit 16, and the volatile memory 20 to measure time.

  Even when the real-time data is updated in the backup state, the real-time data stored in the volatile memory 20 is rewritten in the same manner as in the normal use state described above. That is, since the volatile memory 20 stores the real-time data divided into a plurality of blocks, the volatile memory 20 rewrites only the data of the block in which the real-time data has been updated, and also updates the data indicating that the data in this block has been updated. A flag is raised. Since the real-time clock device 10 uses the volatile memory 20 that consumes less power than the non-volatile memory 18 to measure time, the real-time data stored in the volatile memory 20 can be updated even in a backup state.

  The real-time data stored in the nonvolatile memory 18 is updated as follows. That is, real-time data is updated when a timing signal is generated in the real-time clock circuit 16. As the timing signal, a carry signal generated by measuring time by the real-time clock circuit 16 may be used.

  More specifically, it is as follows. The real-time clock circuit 16 measures time in seconds, minutes, hours, days of the week, days, months, and years by using a source oscillation or the like. When the second is counted, the second register provided in the real-time clock circuit 16 counts from 00 to 59 in 60 hex, and the time from 59 to 00 shifts to the second (lower) register. A carry signal is output to the (upper) register. Each counter that measures the minutes, hours, days of the week, days, and months also performs the same operation as the seconds register. For this reason, for example, a carry signal output from the hour counter to the day counter or the day counter may be used as the timing signal.

  The real-time data stored in the nonvolatile memory 18 is updated, that is, the updated real-time data is transferred from the volatile memory 20 to the nonvolatile memory 18 when the following condition is satisfied. That is, when a timing signal is generated (condition 1), a data update flag indicating that the real-time data stored in the volatile memory 20 has been updated is set (condition 2), and the real-time clock device 10 When the main voltage is supplied to (condition 3), real-time data is transferred. Whether or not the main voltage is supplied to the real-time clock device 10 is detected by the voltage comparator 24. That is, when the voltage comparator 24 detects that the main voltage is supplied to the real-time clock device 10, the voltage comparator 24 outputs the detection result to the control unit 22. For this reason, the control unit 22 stores the data update flag in the volatile memory 20, that the main voltage is supplied, and that the timing signal is generated. Supply current.

  Thereafter, the updated real-time data is transferred from the volatile memory 20 to the nonvolatile memory 18. That is, in the case shown in FIG. 2, since the data update flag corresponding to the nonvolatile memory buffer 0 is set, the data content of the target block (the updated real-time data of the nonvolatile memory buffer 0) is transferred from the volatile memory 20. Transfer to nonvolatile memory 18 and write. When this transfer ends, the current supply to the nonvolatile memory 18 is stopped again. Also, the data update flag of the volatile memory 20 is lowered.

  As a result, current is selectively supplied to the nonvolatile memory 18 and the real-time data stored in the nonvolatile memory 18 is updated. Therefore, the real-time clock device 10 operates at a low voltage and a low current. In addition, the real-time data stored in the nonvolatile memory 18 is not frequently rewritten.

  According to such a real-time clock device 10 and its control method, when the initial power is turned on to the real-time clock device 10 and when real-time data is transferred from the volatile memory 20 to the non-volatile memory 18 for writing. A current is selectively supplied to the nonvolatile memory 18. Therefore, since the current is supplied only when the nonvolatile memory 18 operates, the real-time clock device 10 can reduce current consumption and voltage consumption. Therefore, the real-time clock device 10 can operate at a low voltage and a low current. In addition, the power consumption of the electronic device in which the real-time clock device 10 is mounted is reduced. In particular, when the electronic device is driven by a battery, the battery life is prolonged and the product life can be prevented from being shortened.

  When the real-time data stored in the nonvolatile memory 18 is rewritten, the main voltage is supplied to the real-time clock device 10, so that the access speed to the nonvolatile memory 18 can be increased. Therefore, since writing can be completed in a short time, the current consumption of the real-time clock device 10 can be reduced and the voltage consumption can also be reduced.

  In addition, since the real-time data stored in the nonvolatile memory is rewritten when the above-described three conditions are satisfied, the number of times of rewriting the nonvolatile memory 18 can be reduced. Therefore, the real-time clock device 10 can reduce power consumption by a minimum rewriting operation, and does not reach the upper limit of the number of times that the real-time clock device 10 can be rewritten before the product life of the electronic device is exhausted.

  The real-time clock device 10 described above can be configured to output a reset signal. FIG. 3 is a block diagram of a control unit configured to output a reset signal. In the case of this configuration, the control unit 22, the detection unit 32, and the reset signal output unit 34 are provided in the control unit 22 described above. The control unit 30 controls the detection unit 32, the reset signal output unit 34, the real time clock circuit 16, the volatile memory 20, the nonvolatile memory 18 and the like described above, and detects from the voltage comparator 24 and the power-on reset circuit 26. The result is input. The detecting means 32 detects the end of real-time data transfer from the nonvolatile memory 18 to the volatile memory 20. Further, the reset signal output means 34 outputs a reset signal. The real-time clock device 10 is provided with a reset signal output terminal (/ RST).

  In the case of such a configuration, the operation for outputting the reset signal is as follows. When the real-time clock device 10 is turned on, the real-time data is transferred from the nonvolatile memory 18 to the volatile memory 20 as described above. When this transfer ends, the detection means 32 detects the end of transfer. When receiving the detection result from the detection means 32, the control means 30 performs control so as to stop the current supply to the nonvolatile memory 18 and to output a reset signal from the reset signal output means 34. With this control, a reset signal is output from the reset signal output means 34 to the outside of the real-time clock device 10, that is, to the electronic device via the reset signal output terminal (/ RST).

  With this configuration, the real-time clock device 10 can have a function equivalent to that of a reset integrated circuit with a delay. Therefore, the number of parts of the entire electronic device on which the real-time clock device 10 is mounted can be reduced, and the cost of the electronic device can be reduced.

  Next, a second embodiment will be described. In the second embodiment, description of the same configuration as in the first embodiment is omitted. FIG. 4 is a block diagram of a real-time clock device according to the second embodiment. The real-time clock device 10 according to the second embodiment includes an oscillation circuit 14 including a piezoelectric vibrator 12, a real-time clock circuit 16, a nonvolatile memory 18, a volatile memory 20, a control unit 22, a voltage comparator 24, and a power-on A reset circuit 26 is provided.

  The nonvolatile memory 18 may be the same as that of the first embodiment, and may be, for example, an EEPROM or a flash memory. The nonvolatile memory 18 includes a system area 40 and a user area 42. That is, the nonvolatile memory 18 includes a storage unit for real-time data and identification information (ID-ROM) serving as the system area 40 and a storage unit for user data serving as the user area 42. This identification information is fixed data such as a serial number of the real-time clock device 10 and is set by the manufacturer of the real-time clock device 10.

  The manufacturer can write real-time data and identification information in the system area 40 and can read them. When writing real-time data, the real-time clock device 10 is set to a special mode (test mode). The user of the real-time clock device 10 can read the data in the system area 40.

  In addition, the manufacturer and the user can write and read data in the user area 42. The user area 42 is an area mainly used by the user. Therefore, when the real-time clock device 10 is mounted on an electronic device, the user writes user data in the user area 42 and reads user data from the user area 42. That is, the user area 42 stores user data used by the user.

  The real-time clock device 10 including such a nonvolatile memory 18 has the same control method as the real-time clock device according to the first embodiment. That is, when initial power is supplied to the real-time clock device 10, real-time data, identification information, and user data are transferred from the nonvolatile memory 18 to the volatile memory 20. When this transfer is completed, the current supply to the nonvolatile memory 18 is stopped. The real-time clock device 10 measures time using the oscillation circuit 14 including the piezoelectric vibrator 12, the real-time clock device 10 and the volatile memory 20.

  When updating real-time data or user data, the real-time data or user data stored in the volatile memory 20 is updated for each block, and a data update flag corresponding to this block is set. As a result, it can be seen that the real-time data and the user data are updated. Then, on the condition that the data update flag is set in the volatile memory 20, the main voltage is supplied to the real-time clock device 10, and the timing signal is generated, the nonvolatile memory 18 is loaded. Restart current supply. Thereafter, the updated real-time data and user data are transferred from the volatile memory 20 to the nonvolatile memory 18 and the data content stored in the nonvolatile memory 18 is updated. When this update is completed, the current supply to the nonvolatile memory 18 is stopped and the data update flag set in the volatile memory 20 is lowered.

Such a real-time clock device 10 divides the nonvolatile memory 18 into a system area 40 and a user area 42. For this reason, the electronic device in which the real-time clock device 10 according to the present embodiment is mounted does not need to mount a user area (storage unit for user data) as an external component. On the other hand, the conventional real-time clock device does not have a user area. For this reason, an electronic device equipped with a conventional real-time clock device needs to have a user area as an external component. Therefore, an electronic device equipped with the real-time clock device 10 according to the present embodiment can simplify and reduce the circuit configuration of the electronic device as compared with an electronic device equipped with a conventional real-time clock device. In recent years, there has been a demand for downsizing of electronic devices, and electronic devices equipped with the real-time clock device 10 according to the present embodiment can meet this requirement.
In addition, the real-time clock device 10 and the control method thereof according to the present embodiment can achieve the same effects as those of the first embodiment.

  Note that the real-time clock device 10 including such a nonvolatile memory 18 can be mounted on an electronic device that requires the user area 42. As a specific example, it can be mounted on a digital audio player. Some music data reproduced by a digital audio player can be reproduced only within a certain period of time, and others can be reproduced only by authorized persons. If the music data can be reproduced only within a predetermined time, the reproduction time can be managed based on the time data generated by the real-time clock circuit 16. If the music data can be reproduced only by an authorized person, the reproduction can be managed based on the identification information of the real-time clock device 10, that is, the identification information stored in the system area 40. The user area 42 can store music data and playback information of the digital audio player (music data playback order, sound quality, volume, etc.). For this reason, by providing the user area 42 in the real time clock device 10, various user data used in the digital audio player can be managed by the real time clock device 10, so that the usability is improved and the digital audio player is downsized. it can.

  The real-time clock device 10 according to the present embodiment can also have the configuration described with reference to FIG. That is, the real-time clock device 10 according to the second embodiment can be configured to include the control means 30, the detection means 32, and the reset signal output means 34 shown in FIG. The real-time clock device 10 receives a reset signal to the outside of the device 10 via the reset signal output terminal (/ RST) upon completion of transfer of real-time data from the nonvolatile memory 18 to the volatile memory 20 when the initial power is turned on. Can be output.

It is a block diagram of the real-time clock device concerning a 1st embodiment. It is explanatory drawing of the data block of volatile memory. It is a block diagram of a control unit configured to output a reset signal. It is a block diagram of the real-time clock device concerning a 2nd embodiment.

Explanation of symbols

10... Real time clock device 14... Oscillation circuit 16... Real time clock circuit 18 18 Nonvolatile memory 20 Volatile memory 34 Reset signal output means 40 ... System area, 42 ... User area.

Claims (8)

By turning on the initial power, the real-time data stored in the non-volatile memory is transferred to the volatile memory.
By stopping the transfer of this real-time data, the current supply to the nonvolatile memory is stopped,
Time is measured with a real-time clock circuit using real-time data stored in the volatile memory and a source oscillation input from an oscillation circuit.
A method for controlling a real-time clock device.   2. The method for controlling a real-time clock device according to claim 1, wherein a reset signal is output to the outside upon completion of transfer of the real-time data. Storing in the volatile memory real-time data updates caused by timing in the real-time clock circuit;
When the timing signal is generated and the main voltage is supplied, the current supply to the nonvolatile memory is resumed,
Transferring updated real-time data from the volatile memory to the nonvolatile memory, and rewriting the real-time data stored in the nonvolatile memory;
The method for controlling a real-time clock device according to claim 1 or 2.   4. The control of the real-time clock device according to claim 1, wherein the nonvolatile memory stores real-time data and identification information used by the system and user data used by a user. Method. An oscillation circuit that outputs a source oscillation;
Non-volatile memory that stores real-time data and is selectively supplied with current;
A volatile memory for inputting and storing real-time data from the nonvolatile memory;
A real-time clock circuit for measuring time using source oscillation input from the oscillation circuit and real-time data stored in the volatile memory;
A real-time clock device comprising: An oscillation circuit that outputs a source oscillation;
Non-volatile memory storing real-time data;
A volatile memory that inputs and stores real-time data from the nonvolatile memory, and stores real-time data updated by timekeeping, and
A real-time clock circuit that performs the timing using the source oscillation input from the oscillation circuit and the real-time data stored in the volatile memory;
Detecting initial power-on and supplying current to the non-volatile memory, performing real-time data transfer control from the non-volatile memory to the volatile memory, updating real-time data stored in the volatile memory, and Control for detecting the timing signal generated in the real-time clock circuit and turning on the main power supply, supplying current to the nonvolatile memory, and controlling the transfer of updated real-time data from the volatile memory to the nonvolatile memory And
A real-time clock device comprising:   7. The real-time clock device according to claim 5, wherein the nonvolatile memory includes a storage unit for real-time data and identification information, and a storage unit for user data input from the outside. Detection means for detecting completion of transfer of real-time data from the nonvolatile memory to the volatile memory;
A reset signal output means for obtaining a signal from the detection means and outputting a reset signal;
The real-time clock device according to claim 5, further comprising:

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