JPS6059454A - Count data storing method to eeprom - Google Patents

Abstract

PURPOSE:To suppress the rewriting frequency per area and to detect the final data out of the stored counted data by dividing the maximum number of counted digits and providing a data store area every count value for the lowest-order section. CONSTITUTION:A sensor 40 produces a pulse for each fixed distance traveled, and a display device 60 displays the distance traveled. A data rewriting prevention circuit 80 inhibits the inadvertent rewriting of data, and a data writing prevention circuit 90 prevents the writing of data when a processor 10 has a runaway. An EEPROM30 contains a program area 31 for a fixed memory and a data area 32 which is used like an RAM. Data signals D1 and D2, an address signal A1, a read control signal and a write control signal W1 are transferred to an MPU. A data store area and its corresponding sign store area are provided in order to secure the final data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for storing data in an EEFROM, which is a nonvolatile memory that can be electrically erased, written, and read;
In particular, it relates to a method of storing NI number data.

[Prior art]

In recent years, the development of such EEPROM has progressed, and the peripheral device control and the same 5V single power source are 11J1 stroke 111
19・
- There are great expectations for its use as a decision-making tool.

However, when used as a bulletin board rather than as a temporary backup during a power outage, EEPROM differs from normal RAM in that writing (rewriting) takes place in two stages: erasing and writing. Since it takes a long time to complete the process, there are measures to be taken in the event of an interruption during that time. In other words, it is necessary to determine whether the data read after restarting the operation is the correct final data rather than the meaningless data that was interrupted, or to read the complete data just before the interruption. It is necessary to ensure that accurate data can be obtained. For example, methods have been proposed in which multiple storage areas are provided for one type of data and the final data is determined by majority vote.

Another issue that must be resolved when using EEPROM in a similar manner to RAM is the problem of limiting the number of writes. That is, currently, the number of times an EEFROM can be erased, tlj, and written is about the same as 10.

Therefore, when using this as a force input,
If a specific area is provided and the numbers are simply counted in that area, only the number of times that erasing and writing can be performed can be achieved.

[Summary of the invention]

The present invention was made in view of these circumstances, and its purpose is to always obtain reliable final data regardless of interruptions in writing operations, and to exceed the limit on the number of erasing and writing times for individual areas. It is an object of the present invention to provide a method for storing count data in an IPROM that is capable of counting numbers.

In order to achieve such an object, the present invention divides the maximum number of counted digits into multiple sections in order of digits, provides a counting data storage area for each section for the upper section, and provides one count data storage area for the lowest section. A count data storage area with a number smaller than the maximum count value of the relevant division is provided for each division, and when updating the numerical value, the final data is the one immediately before the natural number sequence is disturbed from the contents of the count data storage area of the lowest division. The updated value is stored in the area of the next rank, and when the updated value becomes 101, the contents of the higher classification are further updated.

Generally, as a method of securing the final data, three or more n data storage areas are provided for each type of data to be stored, and a corresponding signature storage area is provided, and the signature storage areas are assigned a specific rank. It is possible to store n+1 or more different signs, for example, any one of consecutive natural numbers, and when updating data, the last consecutive sign is searched as corresponding to the final data, and the corresponding one is searched. A conceivable method is to store the updated data in the next data storage area of the data storage area, and then rewrite the signature in the corresponding signature storage area to a sign one rank after the last one. Of course, the signature is rewritten as soon as the writing of new data is completed, so that the latest final data can be detected even after a complete write-in, but this method When used to store 1-number data, there is the problem of the limit on the number of writes mentioned above, but in the case of count data, since the data itself is a continuous natural number, it can also be used as a signature. can do.

Therefore, the present invention reduces the number of changes per area by dividing the maximum number of counting digits and providing a data storage area for every seven counting digits in the lowest division. The final data can be detected from the data itself. Regarding the upper divisions, it is possible to use a method of providing three or more data storage areas and signature storage areas for each division as described above, or to use another method, for example, by using the majority voting method as described above, so that the final data can be grasped. Just do it. Hereinafter, the present invention will be explained in detail using Examples.

[Embodiment] FIG. 1 is an 11-1 stage diagram of a system showing an embodiment of the present invention applied to an electronic odometer. In the figure, reference numeral 10 denotes a processor, specifically constituted by, for example, a well-known microprocessor.

20 is RAM and 30 is EEPROM T. Also 4o
is a sensor which inputs a pulse signal PS generated every fixed distance traveled to the processor 1 via an input interface 5o.
Send to 0. Further, 60 is a display that displays the distance traveled, and 70 is a driving circuit thereof, which is controlled by the processor 10. The EEPROM 30 is provided with a program area 31 used as a fixed memory and a data area 32 used similarly to a RAM. Dl is a data signal exchanged between the processor 10 and the data area 32, Dl is a data signal read from the program area 31, and A1 designates the data area or a specific address area of the program area. The address signal, R1, is a read control signal, and Wl is a write control signal.

In the above configuration, the program area 31 is 1, for example, standard diameter tire circumference ← / number of pulses per rotation of tire =
As a person, n (r-11Jt)/A,! The data area 32 is used to store fixed data such as the number of pulses input from the sensor 40 per 100 m that is requested, and the data area 32 is used to store counting data that counts the number of pulses mentioned above. used for Note that 80 is a circuit for preventing rewriting of data that should not be rewritten carelessly, such as the above-mentioned fixed data. By opening the AND circuit AND1 provided on the write control signal line on the condition that all inputs of 1 are inactive, the address where the digit corresponding to the above specific address signal line becomes ``1'' can be determined. This prevents the contents from being rewritten. Further, 90 is a circuit that prevents erroneous data from being loaded when the processor 10 goes out of control, and when the processor 10 is in normal operation, it is repeatedly discharged by the clock pulses sent from the processor to the terminals. The comparator detects that the terminal voltage of the capacitor fct, whose voltage is suppressed below 1 constant level, exceeds the reference voltage B higher than the above-mentioned constant level, that is, in that case, the output of the comparator COMI becomes 0. Since K becomes '°', the AND circuit AND is closed and writing is prohibited.

Therefore, the capacity of EEPROM30 is set to 512 bytes,
Maximum number of counting digits'f: 4 bytes to 32 bits, EE
Divide the PROM30 area into two as shown in the 1fi2 diagram, and place a count data storage area for the lowest byte on one side4.
(i=1 to 255), and on the other hand, g] number data storage areas R2,j, RB,j for the upper 3 bytes.

Hiki, j and sign storage area Nj (-, = 1 to 3)
will be established. 4 bytes =: 32 bits is 4 in lO base
．． 2949 x IU9, which is usually 10 for an odometer.
up to 10,000 km, that is, even if the resolution is 5100 m, it is 10
Since it is sufficient to be able to count times, this is a sufficient number of digits for this purpose. This EEPROM 30 is initialized in advance by external control, and the initialization condition is that the data storage area R of the lowest byte is
], i and upper 3 byte data storage area R2,j
While the contents of +R11jlR4'j are all 1 (month), the signature storage area Nj has α-tJ, 1, 2 .
3 is stored, and the 1 series is made to satisfy the relationship of sign n2;α, n8-α+1, nl;α-1. However, 3+1=0. That is, the signature storage area is used as a ring counter.

In addition, the data storage area R of the lowest byte contains 1 to 2
Although 55 set number data can be accommodated, when the number of sets becomes 256, a carry is performed and the content of the data storage area of the least significant byte becomes "0". That is, the data storage area of this least significant byte is also often used as a ring counter 7. Note that F is an overflow area, which is used to identify whether or not the carry from the least significant byte to the older byte has been correctly performed, as will be described later.

On the other hand, the RAM 20 is provided with a counting data storage area consisting of areas R1 to R4 corresponding to each byte as shown in FIG.
This is done by sequentially storing the new data in each of the data storage areas each time the RAM data changes.

Below, using the flowchart in Figure 4, EEI'ROM
The operation of storing count data into 30 will be explained. That is, FIG. 4 is a flowchart 1 showing an example of an execution program in the processor 10. It goes without saying that a ROM for storing this program is required, but it is omitted in FIG.

'When the power is turned on (the ignition switch is turned on) and program execution starts, the processor 10 in step 101 stores the area R4-j +R8-j +R2-j containing the final data of the upper 3 bytes and its contents r.
4. j+r8. jlr2. Check j. This is done as follows. After sequentially accessing the signature storage areas N1 to N8 and reading out their contents n□ to n, = --- Detecting the last consecutive n from the read signatures n1 to n8. . For example, if the above-mentioned signs are 0 and 1.2, the target sign is 2°, and if it is 3 and 0.1, it is 0. A data storage area R4,j corresponding to the signature storage area Nj that stores the signature n obtained in this way
, R8,j, and R2,j are the areas storing the final data, and rllJ among the contents r4.j+rs is determined to be the final data of 7.

Next, in steps 102 to 105, the entire data storage area R1,i (1 is 1'-255)
'6r1. After reading l, steps 106-10
Immediately before entering 8, that is, r □, i + □ 8 r to 1,
) + "01□6'".For example, if the data in the above name data storage area is as shown in Figure 5, the data immediately before the continuity is disturbed is in area R.
rl, l = "orb," stored in 1, i, and this becomes the final data.

Here, if this final data r+,i is 'oo'', then a carry should have been performed in the previous update, but it is difficult to determine whether the carry was performed correctly or not. It is checked whether or not writing was interrupted midway, and if a carry has not been performed, the carry is performed at this point.

That is, in step 109, Rt,i is 00°'
16, the processor 10 accesses the overflow area F and reads its contents f in step 110. As will be described later, when performing a carry from the least significant byte to the most significant byte, this overflow area F stores the contents of the data storage area R2,j of the least significant byte of the three most significant bytes after the carry. , are written before actually updating area R2,j, so that the content f is the same as the content r2., of area R2,j. If it does not match j, it means that digit ``2'' was not executed correctly. Therefore, in step 111, f-4r2. If j is confirmed, step 112
, 113, store the value obtained by adding "1" to the final data in the area of the next rank that was previously determined to be the final data storage area, and change the sign of the corresponding fin storage area by 1 from the sign corresponding to the final data. After the ranking, change to the ranking sign again.

With the above, the final data for each buy) is confirmed. The above can be called initialization processing.

Hereinafter, the processor 10 monitors the count input and the pulse input from the sensor 40 at a predetermined sampling period, and each time a count input is detected, the processor 10 stores the count data storage area R1 provided in the RAM 20 in step 115. (
Increment the contents of L by 1-11.

Next, the count value on the EEPROM 30 side is updated according to the literary style, but at this time, as a result of the above increment, the content r1 of the area R□ of the least significant byte is "oo".

If so, in step 117, Wr2 of area R2 is written in the overflow area in advance. Next, in steps 118 and 119, the lowest byte data storage area R next to the final data storage area mentioned above is
The data of the area R0 corresponding to the RAM 200 is stored in □, I, and in steps 120 and 121, the RAM 22 is stored in the next highest 3-byte data storage areas R4,j, RB,j, and R2,i of the final data storage area. After sequentially storing the data of the corresponding areas R,, R3, and R2,
The length in of the corresponding signature storage area is rewritten to the signature corresponding to the above final data and ranked one rank after the signature.

If it is determined in step 116 that the updated RAM data □ is not 6, then only the least significant byte of ggpItoM30 is updated in steps 122 and 123.

Since the overflow area F is provided in this way,
The division error due to the interruption of operation can be kept to the minimum decomposition amount. If there is no overflow area F, only the area R, i in the lowest classification will be updated (update result “00”°
□6) If carry-up to a higher category is not carried out, 2
This results in an error of 55 times. .

As explained above, the signatures for the top three categories are rewritten after new data is written to the data storage area, and the signatures detected using the method described above correspond to the final data that has been completely updated. Therefore, even if there is an interruption during writing, the old data before the start of writing can be used as reliable final data when the operation is restarted. To ensure continuity, at least three signature storage areas, and therefore correspondingly data storage areas, are required for each data. In this case, in the embodiment described above, the top three
For example, as shown in FIG. 6, a signature storage area N is created for each byte as shown in FIG.
2, j, N) 1, j, N4, j may be provided.For such n sign storage areas of 3 or more, in order to see the disturbance of continuity, the sign itself is at least 1 or more (, n+1 or more are required. In this case, any sign can be used as long as the order can be specified, or if a specific order is determined and used, but in the above example, It is most practical to use consecutive natural numbers, such as the minimum number of 4, or especially in an 8-bit system, the maximum of 256 that can be included in one word.

The relationship between the length-in storage area and the sign is exactly the same for the lowest bite. In other words, for the least significant byte, the data storage area is used as a signature storage area, and the data itself, which is a sequence of natural numbers, is also used as a signature, but in that case, the number of signatures is the maximum count j&,
, J in the embodiment has 256 signature storage areas from 0 to 255, so the number of signature storage areas, that is, data storage areas that can be set is smaller than that, and is 255 at maximum. This least significant byte is distributed over as many areas as possible to reduce the number of writes to the same area, so in the above-described embodiment, a maximum of 255 data storage areas are set.

According to the method explained above, it is possible to realize a literal electronic odometer using an EEPROM, and compared to a mechanical configuration, it is possible to improve the manpower and make it possible to form a mountain shape, and it also has sufficient accuracy. Guaranteed cumulative mileage display data can be obtained.

It is of course conceivable that the EEPROM 30 may be used in the same way as a RAM, or in the same way as a normal ROM. In other words, subroutines and Baliney/con constants are stored in advance and the processor reads and uses them at any time.If this is the case, for example, the basic routine (specification) is the same, but the If a manufacturer wants to create a product with variations in which the constants have been radically changed, the manufacturer can handle this using only software, dramatically expanding the versatility of the system.

In the above-described embodiment, the program area 31 is used for this purpose, but the fixed data stored therein include, in addition to the mileage value per person capulus mentioned above,
For example, Km/mil@, 17 gallon.

Conversion constant between used units such as kg/pond, minimum display digit (display resolution) is IKm or 100m1
0m or the maximum digit is 11001 (or IO[
)01Gn, 10,000 fat, 100,000 and so on.

Note that this designation of the maximum display digit is safe because in the event of an overflow at the designated digit, it will return to "0".

Although an example in which the present invention is applied to an electronic odometer has been described above, it can be widely applied to stopwatches and other general counters that perform regular counting. Well, basically it can be applied in exactly the same way not only to addition counts but also to subtractive divisors.

〔Effect of the invention〕

As explained above, according to the present invention, the maximum number of divisible digits is divided into a plurality of divisions, and for each count value of the lowest division, the count data storage area is smaller than the maximum count value of the lowest division. When updating the division value, the updated value is stored in the count data storage area next to the area that stores the contents of the division data storage area of the lowest division mentioned above that are immediately before the natural number sequence is disturbed. However, if the updated value is 10-1, the contents of the count data storage area of the upper division, which is provided separately, are updated, so that reliable JP final data is always available regardless of interruptions in writing operations. In addition, it becomes possible to count a number exceeding the limit on the number of erasable and writable times of EEPROM.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a system showing an embodiment of the present invention applied to an electronic odometer, and FIG.
Memory map showing the 141st chapter of M, Figure 3 ij: R
FIG. 4 is a flowchart showing an example of an execution program in the processor; FIG. 5 is a diagram explaining the final data detection method of the lowest division; FIG. 6 is a diagram showing the configuration of the EEPROM. Other 4'f'?
This is a memory map showing an example. 10... Processor, 20... RAM M2O
...EEPROM S 40...Sensor, 50
... Input interface, R1, i ... 11 data storage area of the least significant byte, R4-j lR8
,j +R2,j ...Division data storage area% of upper 3 bytes Nj+N4゛j+Na-j+N2-j ”
"-' In-accommodation K13 area, F... overflow area. Patent applicant: Koito Seisakusho Co., Ltd. Agent: Several Yamakawas (I Shisuna) Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (2)

[Claims] (1) Divide the maximum divisible number of digits into multiple categories in order of digits, provide a counting data storage area for each category for the upper category, and set the maximum count value for each count for the lowest category. A counting data storage area with a smaller number of items is provided, and to update the counting value, the contents of the division data storage area of the lowest division are searched for the content immediately before the natural number sequence is disturbed as the final data, and then the content of the counting data storage area is updated. The method of storing the updated value in the counting data storage area of the next rank, and further updating the content of the counting data storage area of the higher classification when the updated value becomes [01]. Counting data storage method. (2) Digit - An overflow area is provided to identify whether the discrepancy has been performed correctly, and if the final data retrieved for the lowest division is [01, the lowest digit in the upper division is is compared with the contents of the overflow area, and if they do not match, the count value of the upper division is updated. On the other hand, if the updated value of the lowest division is "0", the contents of the data storage area of the upper division are updated. 2. A method for storing count data in an EEFROM according to claim 1, characterized in that the updated value of the least significant digit in the upper division is stored in an overflow area prior to the above.