JPH03216588A - Standard time clocking apparatus - Google Patents

Abstract

PURPOSE:To output a standard time without being affected by the manufacturing deviation of internal oscillation frequency and to enhance accuracy by storing the value corresponding to the manufacturing deviation of an oscillator in a non-volatile memory as the set value of a subtraction counter. CONSTITUTION:A clock becoming a standard is supplied into an apparatus from an external oscillator 1 and the adding counter 3 for the external oscillator 1 performs up counting by the control of a start switch 2. After the completion of counting, a start flip-flop 4 is stopped and this state is informed to a writing control part 5 at the same time. An up counter 6 for an internal oscillator 10 is operated by the clock of the internal oscillator 10 to start counting simultaneously with the up counter 3 for the external oscillator and both counters stop simultaneously. This count is stored in a writing non-volatile memory 7 and standard time output S bringing the count to zero is sent out. Thereafter, this setting and output is repeated to perform the operation as clock function.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is applied to digital circuits. The present invention relates to a reference time clock for measuring instruments.

〔overview〕

The present invention provides a reference time clock device that includes a built-in oscillator and calculates a reference time, and by storing a value corresponding to the manufacturing deviation of the oscillator in a non-volatile memory as a set value of a subtraction counter, the internal oscillation frequency can be manufactured. This allows the standard time to be output without being affected by deviations, increasing accuracy.

[Conventional technology]

Conventionally, this type of reference time clock device has calculated the reference time by increasing the frequency accuracy of a built-in oscillator and dividing the frequency.

[Problem that the invention seeks to solve]

The conventional reference time clock device described above performs addition and division based on a highly accurate oscillation frequency and a highly stable frequency, so it does not have the ability to track absolute time and the oscillator is not close to the designed value. This has the disadvantage of increasing the clock error,
In addition, there was a drawback that variations due to individual differences could not be defined by anything other than the accuracy of the oscillation frequency.

That is, although fluctuations in the internal oscillator can be controlled to be small by temperature control or the like, errors due to manufacturing deviations cannot be reduced.

SUMMARY OF THE INVENTION The present invention aims to eliminate these drawbacks, and aims to provide a device that improves the accuracy of the internally generated reference time and allows the reference time to be set without being affected by variations in the internal oscillation frequency. .

[Means for solving problems]

The present invention includes an internal oscillator and a subtraction counter that performs subtraction counting using the output of the internal oscillator as a clock signal,
The reference time clock device whose reference time output is from the start to the end of counting of the subtraction counter is characterized by comprising a setting means for setting an initial value to be set in the subtraction counter in accordance with a manufacturing deviation of the internal oscillator.

The setting means includes a terminal for connecting a standard external oscillator, an external oscillator addition counter that counts clock signals applied to this terminal up to a predetermined value, and an internal oscillator addition counter that counts the output of the internal oscillator. , means for stopping counting of the internal oscillator adding counter when the external oscillator adding counter reaches a predetermined value, and storing the counted value of the internal oscillator adding counter when counting is stopped by this means. The stopping means includes a non-volatile memory and means for applying the stored contents of the non-volatile memory to the subtraction counter for each output of each reference time, and the stopping means includes:
It is set by a start signal given from the outside, and is reset when the addition counter for the external oscillator counts a predetermined value, and the output is the human power that controls the operation of the addition counter for the external oscillator and the human power that controls the operation of the addition counter for the internal oscillator. can include a flip-flop given to

[Effect]

When setting the initial value, when receiving a highly accurate and stable frequency oscillation clock and start instruction signal from the external oscillator and start switch connected via the terminal, the external oscillator addition counter starts adding up to the count value corresponding to the reference time. At the same time, the internal oscillator addition counter performs addition counting. When the addition counter for the external oscillator completes the count corresponding to the reference time, stop the addition count of the addition counter for the internal oscillator, store the value at this time in non-volatile memory, set that value to the subtraction counter, and set the subtraction counter. The time required to count from the value to zero is the reference time.

This makes it possible to improve the accuracy of the internally generated reference time, and to set the reference time without being affected by internal oscillation frequency variations.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

The figure is a block diagram showing the configuration of an embodiment of the present invention.

The embodiment of the present invention includes an internal oscillator 10 and an internal oscillator 1.
The setting means includes a subtraction counter 9 that performs subtraction counting using the output of 0 as a clock signal, and a reference time control section 8 that sets an initial value to be set in the subtraction counter 9 according to manufacturing deviation of the internal oscillator. , a terminal 11 for connecting a standard external oscillator 1, an external oscillator addition counter 3 that counts the clock signal applied to this terminal 11 up to a predetermined value, and an internal oscillator addition counter 6 that counts the output of the internal oscillator 10. and external oscillator addition counter 3
means for stopping the counting of the internal oscillator addition counter 6 when the count reaches a predetermined value; a non-volatile memory 7 for storing the counted value of the internal oscillator addition counter 6 when counting is stopped by this means; The start flip-flop 4 is set by a start signal given from the external start switch 2, and is set by a start signal given from the external start switch 2, and is set by a start signal given from the external start switch 2. 3 includes a start flip-flop 4 which is reset when the counter 3 counts a predetermined value and whose output is given to the operation control input of the addition counter 3 for the external oscillator and the operation control input of the addition counter 6 for the internal oscillator.

A reference clock is supplied internally from the external oscillator 1, and an external oscillator addition counter 3 performs addition counting under the control of the start switch 2. When counting is completed to a count value corresponding to the reference time, a completion signal S1 is sent out, the start flip-flop 4 is stopped, and the write control unit 5 is notified at the same time.

The internal oscillator addition counter 6 operates with the clock of the internal oscillator 10, and starts counting at the same time as the external oscillator addition counter 3 and stops at the same time. The count value of this internal oscillator addition counter 6 is stored in the nonvolatile memory 7 under the control of the write control unit 5, and the reference time control unit 8 sets this information in the subtraction counter 9 so that the count value becomes zero. When this happens, the reference time output S2 is sent out. Thereafter, by repeating such settings and outputting the reference time, it can operate as a clock function.

〔Effect of the invention〕

As explained above, according to the present invention, the reference time can be set without being affected by variations in internal oscillation frequency, and the accuracy can be improved.

[Brief explanation of drawings]

The figure is a block diagram showing the configuration of an embodiment of the present invention. 1...External oscillator, 2...Start switch, 3.
...Additional counter for external oscillator, 4.Start flip-flop, 5.Write control unit, 6.Additional counter for internal oscillator, 7.Nonvolatile memory, 8.
Reference time control unit, 9... Subtraction counter, 10... Internal oscillator, 11... Terminal, S1... Completion signal, S2
...Reference time output.

Claims (1)

[Claims] 1. A reference time clock device comprising an internal oscillator and a subtraction counter that performs subtraction counting using the output of the internal oscillator as a clock signal, and whose reference time output is from the start to the end of counting of the subtraction counter. A reference time clock device according to claim 1, further comprising a setting means for setting an initial value to be set in the subtraction counter in accordance with a manufacturing deviation of the internal oscillator. 2. The setting means includes a terminal for connecting a standard external oscillator, an external oscillator addition counter that counts the clock signal applied to this terminal up to a predetermined value, and an internal oscillator addition counter that counts the output of the internal oscillator. a counter; means for stopping counting of the internal oscillator adding counter when the external oscillator adding counter reaches a predetermined value; and means for stopping counting of the internal oscillator adding counter when counting is stopped by this means. 2. The reference time clock device according to claim 1, further comprising: a nonvolatile memory for storing data; and means for applying the stored contents of the nonvolatile memory to the subtraction counter each time each reference time is output. 3. The stopping means is set by a start signal given from the outside, is reset when the external oscillator addition counter counts a predetermined value, and outputs an output from the operation control input of the external oscillator addition counter and the internal 3. The reference time clock device according to claim 2, further comprising a flip-flop applied to an operation control input of the oscillator addition counter.