JPH01141392A - Elapsed time calculator - Google Patents

Abstract

PURPOSE:To obtain the always adequate elapsed time by providing a means for correcting the elapsed time which adds the number of days of a reference date to the result of subtraction when the result of the subtraction after the subtraction of the reference date from the present data is negative. CONSTITUTION:A present date counter A includes a present year counter 7, a present month counter 8, a present date counter 9, a leap year deciding circuit 10 and a month-year correcting circuit 11 and counts the present date and month. A reference setting counter B includes a reference year counter 12, a reference month counter 13, a reference date counter 14, a leap year deciding circuit 15, and a month end correcting circuit 16, and sets the reference date which is the basis for calculation of the elapsed time. This reference data setting counter B and a CPU 1 constitute the means for correcting the elapsed time which adds the number of days of the reference month to the result of the subtraction if the result of the subtraction after the subtraction of the reference date from the present date is negative.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an elapsed time calculation device that automatically calculates the number of days that have passed from an arbitrary reference date to the current date, and is used to display time on various devices such as cameras and clocks. This is commonly used for equipment, etc.

[Background of the Invention] Conventionally, as a camera data imprinting device, an elapsed time calculation device that calculates the elapsed time from a reference date to the current date has been proposed. The system is configured so that the number of days that have passed up to the current date can be automatically calculated using three display units: year, month, and day.

However, with the above elapsed time calculation device, if the result of subtracting the reference date from the current date is negative, it is difficult to understand what is going on, which is very inconvenient.

[Object of the Invention] An object of the present invention is to provide an improved elapsed time calculation device that can always perform accurate elapsed time calculations.

[Summary of the Invention] The improved elapsed time calculation device according to the present invention includes an elapsed time calculation means for calculating the elapsed time from the reference date to the current date by subtracting the reference date from the current date; If the subtraction result obtained by subtracting the reference date from is negative, subtract one elapsed month from the elapsed time and calculate the number of days after the reference date in the reference month to which the reference date belongs. It is characterized by being provided with an elapsed time correction means for adding the elapsed time to the elapsed time, and further,
The elapsed time correction means includes means for changing the number of days to be added to the elapsed time by determining whether or not the year to which the reference month belongs is a "leap year" when the reference month is February. Based on the above configuration, it is possible to always accurately calculate the elapsed time, and therefore, it is possible to avoid errors in the data captured by the camera or errors in the display of elapsed time on the clock. It can be prevented. - [Embodiments of the Invention] The present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a central processing unit (hereinafter referred to as CP
(abbreviated as u). 2 is an oscillation circuit, 3 is an oscillation circuit 2
A frequency dividing circuit divides the output of Cl1P and inputs a clock pulse of a predetermined period to the CLK terminal of Cl1P1, 4 is a memory composed of RAM, 5 is a memory composed of ROM,
Reference numeral 6 denotes a day pulse generating circuit which further divides the frequency of the clock pulse which is the output signal of the frequency dividing circuit 3 to generate a day pulse representing the day.

Note that 4 is a memory for inputting and outputting data, and 5 is a memory in which program contents are stored.

Block A surrounded by a dotted line in the upper part of FIG. 1 constitutes a current date counter that counts the current date, and within this block A are a current year counter 7, a current month counter 8,
It includes a current day counter 9, a leap year determination circuit 10, and a month-end correction circuit 11.

The current year counter 7 generates an output representing the last two digits of the current year, which output is sent to the input port Y of the cpu t.
Powered by φ~Y5 boat.

The current month counter 8 produces an output representing the current month number, which output is input to the Mφ-M3 ports of the cpu t.

Current day counter 9 produces an output representing the current day, which output is input to ports Dφ-D4 of cpu t.

The leap year determination circuit 10 determines “ from the output of the current year counter 7.
This is a known circuit that determines whether it is a leap year.

The month-end correction circuit 11 uses the output of the current month counter 8 and the output of the leap year determination circuit 10 to determine whether the current month is a large month (a month with 31 days), a small month (a month with 30 days), or a February (28 days in a non-leap year). This circuit determines whether it is the current day (or the 29th day in a leap year) and generates a month-end correction signal to the current day counter 9.

On the other hand, block B on the right side of FIG. 1 represents a reference date setting counter for setting a reference date that is a reference for elapsed time calculation, and this counter includes a reference year counter 12, a reference month counter 13, and a reference date counter 14. In addition to this, it also includes a leap year determination circuit 15 and a month-end correction circuit 16.

The base year counter 12 is a counter that counts the number of years in the Western calendar, the base month counter 13 counts the number of months, and the base date counter 14 is a counter that counts the number of days.

The output of the base year counter 12 is the boat SYφ of cpu t.
~SY5 is manually operated, and the output of the reference month counter 13 is [:P
Boats SMφ to SM3 of tl 1 are operated manually. Also,
The output of the reference date counter 14 is CPU i's boat SDφ
~SD4, the outputs of the month-end correction circuit 16 are input to the ports DMφ~DM4 of CPt11, respectively.

Like the month-end correction circuit 11 of block A, the month-end correction circuit 16 not only generates a month-end correction signal for correcting the count of the reference day counter 14, but also generates the number of days in the reference month as 5-bit information and outputs it to the CPU t's DMφ. ~Input on DM4 boat.

Current year counter 7, current month counter 8, current day counter 9, reference year counter 12) Reference month counter 13 and reference date counter 14 are controlled by a data correction pulse signal generated from a data correction pulse generation circuit 17. The circuit 17 selects one of the six counters when the switch 18 connected to it is closed, and applies a modified increment pulse to the selected counter when the switch 19 is closed. Apply.

The lower left block C in FIG.
7 is included. The decoder 21 decodes the contents of the upper digits of the elapsed time generated from the output ports PHφ to PH5 of the CPU 1, and decodes each of the two digits in the upper digit display section 24.
Generates an output to a driving element for driving the display element of the segment. The decoder 22 decodes the contents of the lower two digits of the elapsed time generated from the output ports PLφ to PL4 of the CPU t, and outputs an output to the driving element for driving the seven segment display elements of each digit in the lower digit display section 25. Occur. Therefore, the decoders 21 and 22
7 output ports SHφ~5 for each digit of 4 and 25
)16. The decoder 23 having SLφ to SL6 is a decoder that generates a driving output for the unit display sections 26 and 27 representing the unit of elapsed time (year, month, day), and is connected to the output port YM/MD CT of the CPU t.
The output signal generated at RL is decoded, and an output is sent to a driving element for driving a display element of a segment representing an upper unit (year or month, i.e., y or m) and a lower unit (month or day, i.e., m). Alternatively, an output to a driving element for driving the display element of the segment representing segment d) is generated from three output ports Cφ to C2.

FIG. 2 is a table showing the correspondence between the boat address and contents of each input/output port of the CPU 1 and the memory address.

FIG. 3 is a table showing the month-end correction circuit output (DM ratio output) determined based on the base year and base month.

FIG. 4 shows a flowchart of a program executed within CPU i.

FIG. 5 shows the configuration of the decoder 23, the unit display parts 26 and 2.
7 is a diagram illustrating a configuration of segments in 7 and an outline of electrical connection between each segment and a decoder 23. FIG.

The contents of the current year counter 7, current month counter 8, and current day counter 9, and the contents of the base year counter 12, base month counter 13, and base date counter 14 are always CPU
The contents of memory 4 are taken in to memory 4 through the input port of cpu t, while the contents of memory 4 are transferred to the output port PHφ of cpu t.
It is input to decoders 21 and 22 from PH5 and PLφ to PL5.

Next, the operation of the apparatus of this embodiment will be explained with reference to FIGS. 1 to 5.

When a power switch (not shown) is turned on, the CPU 1 becomes operational and a program is executed according to the flowchart of FIG.

In Figure 4, when the program starts, the CPU
i starts execution from step #01. That is,
The number of elapsed days (PD) is determined by subtracting the reference date (SD) from the current date (D) stored in the memory 4 or the output of the current date counter 9. Step #0
2, determine whether (PD) is positive or negative, and if it is positive, proceed to step #06, subtract the output (SM) of the standard month counter 13 from the output (M) of the current month counter 8, and calculate the number of elapsed months (
PM), the process proceeds to step #07.

On the other hand, if PD is negative in step #02, the number of days in the base month (if the base date is a leap year, the number of days is “2”).
After proceeding to step #03 where 9” (DM) is added to the number of days of wear (PD), in step #04 the current blade M
) to find the number of elapsed months (PM) by subtracting the reference month (SM). Then, proceed to step #05, and after subtracting 1 from the number of elapsed months (PM) to offset the addition of the number of days (DM) in the reference month to the number of elapsed days (PD), proceed to step #07. .

In step #07, it is determined whether the number of elapsed months (PM) is positive or negative, and if (PM) is positive, the process proceeds to step #11, and the number of elapsed years is calculated by subtracting the reference year (SY) from the current year (Y). After determining (P, Y), proceed to step #12.

On the other hand, if the number of elapsed months (PM) is negative, in the next step #08, after adding 12 to the number of elapsed months (PM),
Proceed to step #09. In step #09, step #
As in step #11, after subtracting the base year (SY) from the current year (Y) to obtain the number of elapsed years (PY), the process proceeds to step #10. In step #10, 1 is subtracted from the number of years elapsed (PY) using the same method as in step #5, and then step #1
Proceed to step 2.

Step #12 determines whether or not the number of years elapsed (PY) obtained in steps #10 and #11 is negative, and if it is negative, the reference date is set after the current date. There will be. In step #16, the number of months elapsed (P
M) After the value is set to 0 and the number of elapsed days (PD) - 0, the process moves to step #17.

On the other hand, if the number of elapsed years (PY3) is not negative in step #12, it is determined in step #13 whether (PY)=0, and if (py)=o, step #1
If (py)≠0, proceed to step #14. If (py)=o or (py)<o, proceed to step #17 as the upper digit (PH) of the elapsed time display. While the number of months (PM) is output, the number of elapsed days (PD) is output as the lower digit (PL) of the elapsed time display.

Then, proceeding to step #19, YM of cpt+i
/MD CTRL boat output is “H” (high level)
As shown in FIG. is excited to the shape of "m (month)", while the segment of the unit display section 27 is excited to the shape of "d (day)"
", and the elapsed time is displayed as "X month, X day (or "xmxd").

On the other hand, if it is determined in step #13 that the number of elapsed years (PY)≠0, the number of elapsed years (PY) is set as the upper digit (PH) of the elapsed time display in step #14, and
The number of months elapsed (PM) as the lower digit (PL) of the elapsed time display
, respectively. Next, when moving to step #18, YM/MD CT of cpot
Since the output level of the RL port becomes L'' (low level), the output level of the Cφ terminal and C1 terminal among the three output terminals of the decoder 23 becomes 'H'' (low level), as shown in FIG.
As a result, the segment of the unit display section 26 is lit in the shape of "y (year)", and the unit display section 26 is lit in the shape of "y (year)".
The segment No. 7 is lit in the shape of "m (month)". Therefore, the elapsed time is displayed as "X months, X months" (or xyxm).

Note that each of the counters 7 to 9 representing the current day is connected to a carry-in and a carry-out, respectively.
Since the pulses generated every other day by the day pulse generation circuit 6 are input to the current day counter 9, the current year, month, and day counters 7.8.9 operate as a normal calendar, so as time passes, the current The day also increments (advances), and the elapsed time display also increments (changes) accordingly.

[Effects of the Invention] As explained in the above embodiments, in the device of the present invention, when the reference date is subtracted from the current date, if the subtraction result is negative, the number of days of the reference blade is added to the subtraction result. Since the elapsed time correcting means (consisting of the part included in block B in FIG. 1 and the part of CPU 1 related to the part) is provided, the inconveniences seen in conventional similar devices are eliminated, and the The elapsed time can be calculated appropriately, and accurate display can be performed on the display unit or the like.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of the elapsed time calculating device of the present invention, and FIG. 2 is the content of input and output at the input/output port of the central processing unit in the device shown in FIG. 3 is a table showing the contents of the output from the month-end correction circuit 16 in the device shown in FIG. 1, and FIG. A flowchart of the program to be executed, FIG. 5 shows the decoder 23 and unit display unit 26 included in block C shown in FIG.
and 27. FIG. 1... Central processing unit 2... Oscillation circuit 3... Frequency dividing circuits 4 and 5.
... Memory 6 ... Day pulse generation circuit 7 ... Current year counter 8 ... Current month counter 9 ... Current day counter 10 ... Leap year correction circuit 11 ... Month-end correction circuit 12 ... Base year counter 1
3... Base month counter 14... Base day counter 15... Leap year correction circuit 16... Month end correction circuit 17-... Data correction pulse generation circuits 21-23... Decoder 24... Upper digits Display section 25...lower digit display section 26
and 27...unit display section

Claims (2)

[Claims] (1) An elapsed time calculation means for calculating the elapsed time from the reference date to the current date by subtracting the reference date from the current date, and a subtraction result obtained by subtracting the reference date from the current date by the calculation means. If the value becomes negative, an elapsed time correction means is provided that subtracts one month from the elapsed time and adds the number of days after the reference date of the reference month to which the reference date belongs to the elapsed time. An elapsed time calculation device characterized by: (2) In claim 1, when the base month is February, the elapsed time correcting means determines whether the year to which the base month belongs is a "leap year" or not. An elapsed time calculation device comprising means for changing the number of days added to elapsed time.