JP2603005B2 - Counter using non-volatile memory - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a counter using a non-volatile memory which can be restored even if the count value is destroyed by a failure at the time of writing.

[0002]

2. Description of the Related Art Generally, in a device such as a printer, count data indicating the number of operation times of the device, for example, the number of printed sheets, is stored in a counter of a nonvolatile memory in the device in order to manage the replacement time of maintenance parts and consumables. In this case, the counter is updated by +1 each time the device operates.

FIG. 6 shows a conventional example of operation count management using a counter in a printer. 6, reference numeral 1 denotes a printer, 2 denotes a print control unit, 3 denotes a nonvolatile memory such as an EEPROM, 4 denotes a counter, and 5 denotes a display. For example, in the case of page format printing, the print control unit 2 performs a +1 update process of the counter 4 when printing of one page is completed. First, the value (referred to as Ci) of the counter 4 is read from the nonvolatile memory 3 to calculate Ci + 1, and is written into the nonvolatile memory 3 via a write control circuit (not shown). This operation is repeated each time the print control unit 2 executes printing of one page. The counter 4 is read at an appropriate timing and displayed on the display 5.

[0004]

In the conventional method of managing a counter using a nonvolatile memory, a failure such as a power failure occurs while the count data read from the counter and updated by +1 is written to the nonvolatile memory. When it occurs,
In some cases, the count data is lost due to a write failure, which may cause a significant problem in the maintenance service of the apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to enable automatic recovery even if count data is lost due to a writing failure of a counter provided in a nonvolatile memory.

[0006]

According to the present invention, the counters provided in the nonvolatile memory are multiplexed into three or more counters, and the counters are linked in a loop. By selecting and updating only one counter in order, the count value is divided into a plurality of counters, and a plurality of recent update histories are always held in the plurality of counters. Thus, even if a failure occurs during updating of a certain counter and the count value is destroyed, the original count value can be automatically restored by referring to the value of another counter.

FIG. 1 shows the basic configuration of the present invention using a specific example of a printer. In FIG. 1, 1 is a printer, 2 is a print control unit, 3 is a non-volatile memory,
a, 4b, and 4c are counters, 5 is a display, and 6 is a counter control program. Reference numeral 7 denotes a pointer for sequentially and cyclically specifying addresses of the counters 4a to 4c.

Reference numeral 8 denotes a counter update function, which accesses one of the counters 4a to 4c at the address indicated by the pointer 7 in response to a print number update request based on the execution of printing one page, reads out the count data, and adds +1. At the same time, a process is performed in which the value of the pointer 7 is cyclically advanced by one in 4a to 4c.

Reference numeral 9 denotes a counter reading function, which reads out the count values of the counters 4a to 4c and sums them up or accesses one of the counters 4a to 4c indicated by the pointer 7 in response to a print number read request and counts the count data. Is read, a count value obtained by synthesizing all the counters determined based on the read count data and the position of the counter is obtained, and output to the display 5 or the like.

Reference numeral 10 denotes a counter recovery function which responds to a counter recovery request issued when a failure such as a power failure occurs during writing back of the update count data to one of the counters 4a to 4c. 4c, and corrects the correct count data of the counter that may have failed in the write-back immediately before from the count data of the other two counters and corrects it.

[0011]

FIG. 2 shows a sequence of the counter operation according to the configuration of the present invention shown in FIG. 2, reference numeral 11 denotes the number of printed sheets in the printer, 12 denotes individual count data of the counters 4a, 4b, 4c, and 13 denotes counters 4a, 4b, 4
It is a count value obtained by adding the individual count data of c. The underlined value in the column of the count data 12 indicates data updated by +1.

As shown, the counters 4a, 4b, 4c
Are sequentially and cyclically updated by +1 from the initial value 0 each time one print is performed. As a result, the counters 4a, 4n, 3n-3n + 3 are generalized as shown (n = 0, 1, 2,...).
The pattern of the difference between the count data values of 4b and 4c is fixed to 3 types of 4a 4b 4c N + 1 N N N + 1 N + 1 N N + 1 N + 1 N + 1 depending on the position of the counter to be updated by +1. Even if the count value is destroyed, the correct count value can be uniquely recovered from the count data of the remaining two counters that have been correctly updated before that.

That is, in the pattern, if the writing of the counter 4a is normal, the count values of the counter 4b and the counter 4c match, the count data of the counter 4a becomes larger by one, and the pattern is
If the writing of data is normal, the counters 4a and 4b
And the count data of the counter 4c becomes smaller by one, and if the writing of the counter 4c is normal, the three counters 4
This indicates that the count data of a, 4b, and 4c match. Therefore, if a pattern that does not match any of the above-described patterns occurs after the writing to a certain counter is completed, it is determined that an abnormality has occurred and that a writing failure has occurred.

According to the present invention, for example, if a writing failure occurs due to a power cut or a power failure while counting the number of prints in a printer, the count value of each counter is diagnosed at the next power-on, and if there is an abnormality, The recovery process is performed. At that time, the counter recovery function 10 of FIG. 1 performs the following processing. (1) If the counters 4b and 4c have the same value, the counter 4a is not the same, and the counter 4a is not a value larger than the counters 4b and 4c by one, it is known that the writing of the counter 4a has failed. Failure of the writing of 4a means that an attempt to write a value larger than the counters 4b and 4c by one failed, and is restored by writing a value larger than the counters 4b and 4c to the counter 4a. (2) When the value of the counter 4a is larger than the value of the counter 4c by 1 and the value of the counter 4b is not the same, it is understood that the writing of the counter 4b has failed.
Failure of the writing of the counter 4b means that an attempt to write the same value as the counter 4a has failed, and the counter 4b is restored by writing the same value as the counter 4a. (3) The counters 4a and 4b have the same value,
If the counter 4c is not the same and the counter 4c
Is not less than the value of the counters 4a and 4b by one, it means that the writing of the counter 4c has failed,
Failure of writing of the counter 4c means that an attempt to write the same value as the counters 4a and 4b has failed, and the counter 4c is restored by writing the same value as the counters 4a and 4b.

[0015]

FIG. 3 shows a hardware configuration of a printer according to an embodiment of the present invention. 3, reference numeral 14 denotes a CPU for executing print control, 15 denotes a ROM in which control programs such as a counter control program 6 (FIG. 1) and control data are stored, and 16 denotes an R used for a work area such as print data.
AM and 17 are a printer mechanism, and 18 is a non-volatile memory EEPROM provided with counters 4a, 4b and 4c (FIG. 1) according to the present invention.

The CPU 14 executes print control in accordance with a control program in the ROM 15, and based on print data set in a work area of the RAM 16, a printer mechanism 17.
And print out. Here, in the case of a page printer, the counter update function 8 of the counter control program 6 is activated every time the printing output of one page is completed, and the counters 4a, 4b, 4c of the EEPROM 18 are updated in order to increment the count of the number of printed sheets by one. .

FIG. 4 shows a processing flow of the counter updating function 8. When one sheet is printed, the counter updating function 8 operates in response to a print number update request, and 3N + 1 in the sequence of FIG.
If it is the third sheet, the counter 4a is updated by +1. If it is the 3N + 2 sheet, the counter 4b is updated by +1. If it is the 3N + 3 sheet, the counter 4c is updated by +1.

When there is a request to read the number of printed sheets, the count data of each of the counters 4a to 4c may be summed up to obtain the number of printed sheets, but the characteristics of the count sequence shown in FIG. Then, the number of prints can be obtained from only the count data of one counter pointed by the pointer 7 in FIG.

That is, if the counter indicated by the pointer 7 is 4a and the value is N + 1, the number of printed sheets is 3N.
+1 sheets, the counter is 4b, and the value is N + 1.
, The number of prints is 3N + 2, and if the counter is 4c and the value is N + 1, the number of prints is 3N +
It becomes three sheets. However, in this case, it is premised that there is no abnormal count value due to writing failure in each counter.

The recovery from the writing failure in the counters 4a to 4c is performed by an initialization process when the power is turned on. FIG. 5 shows the processing flow. The contents of the counters 4a to 4c are read from the EEPROM 18, and it is checked whether or not the pattern matches one of the above-mentioned normal patterns. If it matches, it is determined that the pattern is normal and the next processing is performed. Specifies which of the counters 4a to 4c is abnormal.

Thereafter, if the counter 4a is abnormal, the value of the counter 4b is incremented by 1 and stored in the counter 4a.
And if the counter 4c is abnormal, the counter 4c stores the value of the counter 4b in the counter 4c, thereby restoring the counter to the normal state.

Incidentally, the counter recovery processing can be executed by an external instruction. Further, the present invention is not limited to application to a printer, and can be widely used in a system in which the number of times of occurrence of any event is managed by a counter provided in a nonvolatile memory.

Further, the number of multiplexed counters may be three or more, for example, four, and the +1 update may be performed cyclically. In that case, the control of the counter becomes complicated, but the reliability of the restoration processing can be improved by the redundancy of the counter.

[0024]

According to the present invention, in a system for managing the number of times using a counter provided in a nonvolatile memory, automatic recovery is performed even if the count data is destroyed due to a failure in writing the updated count data to the counter.
The reliability of the number control can be significantly improved. In addition, there is no need to add special hardware, and the cost can be increased only slightly.

[Brief description of the drawings]

FIG. 1 is a diagram showing the basic configuration of the present invention.

FIG. 2 is an explanatory diagram of an operation sequence of a counter according to the present invention.

FIG. 3 is a configuration diagram of a printer according to an embodiment of the present invention.

FIG. 4 is a processing flowchart of a counter updating function in the embodiment of the present invention.

FIG. 5 is a processing flowchart of a counter recovery function in the embodiment of the present invention.

FIG. 6 is an explanatory diagram of an example of a conventional operation count management of a printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 2 Print control part 3 Non-volatile memory 4a-4c Counter 5 Display 6 Counter control program 7 Pointer 8 Counter update function 9 Counter read function 10 Counter recovery function

Claims (2)

(57) [Claims] A plurality of counters provided on a nonvolatile memory, and one of the plurality of counters is sequentially and cyclically selected in response to a +1 update request for the counters. A counter control program having a counter updating function of updating the count data by +1; dividing and holding the count value by the plurality of counters; and outputting the sum of the count data of the plurality of counters as the count value. A counter using a nonvolatile memory. 2. The counter control program according to claim 1, wherein the counter control program detects a count data of an abnormal value from a correlation between count data of the plurality of counters and recovers the count value to a normal value. A counter using a non-volatile memory characterized by having.