JPS62245600A - Data memory system using non-volatile memory - Google Patents

Abstract

PURPOSE:To improve the utilization of the non-volatile memory of a combination of a static RAM and an E<2>PROM by moving a memory operation to the area of the E<2>PROM in which the rewriting limit number of times reach is detected to other area. CONSTITUTION:An area instructing pointer area, areas No.1-No.i or the like are provided in the E<2>PROM forming the non-volatile memory together with the static RAM by rewriting the contents of memory mutually. In the respective areas No.1-No.i a storing number of times counting part an a data part are provided, and the rewriting number of times is detected and written in the storing number of times counting part. When the rewriting number of times reaches the rewriting limit number of times, the area which does not reach the limit number of times through the area instructing pointer is designated and the memory operation is carried out. Accordingly, the rewriting limit number of the E<2>PROM in which the rewriting limit number is smaller than the static RAM is increased and the utilization of the non-volatile memory combining the static RAM with the E<2>PROM is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data storage system using non-volatile memory. The data storage method according to the present invention can be applied to, for example, a numerical control program automatic creation device used for a numerical control device, a numerically controlled machine tool, etc.

[Prior art and problems to be solved by the invention]

Generally, a combination of electrically erasable programmable read-only memory E2FROM, static random access memory S, and RAM is used as a form of memory device used for data storage in numerical control devices, automatic numerical control program creation devices, etc. Non-volatile random access memories are manufactured and commercially available. (For example,
lcor X 2210 A) E”FROM and S,
An example of a nonvolatile random access memory derived from a combination of RAMs is shown in FIG. The nonvolatile random access memory 1 is composed of a combination of an E''FROM 2, an S, and a RAM 3. The RAM 3 is connected to an external circuit 4.

E"FROM2 is non-volatile), S, RAM 3
is volatile. Based on the store signal from the external circuit, the contents of S and RAM are copied to E2FROM, and based on the recall signal from the external circuit, the contents of S and RAM are transferred to E'FROM.
Contents of M S, Copied to RAM The problem with memory is that it is necessary to take into account the limit on the number of times E"FROM can be rewritten.

That is, in the nonvolatile memory shown in FIG.
There is a limit to the number of times the entire contents of M3 are copied to E"FROM.The entire contents of S, RAM3 are copied to E"FROM.
When N is the number of times a player is co-opted, N has a guaranteed value. The guaranteed value of this N is io, ooo or 100.0
When a copy is performed on E"FROM2, which is 00, there is a limit to the number of times the data changes in each bit of E"FROM2.If n is the number of changes for each bit of E"PROM. , nK also have a guaranteed value. The guaranteed value of n is 1.000 to 10.000.

In this way, as understood from the above-mentioned circumstances, the number of copies N from RAM 3 to E"PROM and the number of changes for each bit of E"FROM, n, in the nonvolatile memory shown in FIG. The number of rewrites of "FROM 2" is regulated not by N but by nK, which is a relatively small value.In this way, in a nonvolatile memory consisting of a combination of E'FROM, S, and RAM, E"FROM
A problem arises in that it is necessary to consider the limit on the number of times the data can be rewritten.

In view of the above-mentioned problems, the present invention provides a non-volatile memory consisting of a combination of E'' FROM and S RAM.
By increasing the number of rewrites of E"FROM,
[Means for solving the problem] In the present invention, the number of stores and the number of rewrites per bit are predetermined. non-volatile random number access memory with a limited number of bit-by-bit rewrites, consisting of static random access memory and electrically erasable programmable read-only memory; A means for detecting that the limit number of times has been reached for each region in a plurality of regions provided in the nuclear volatile random access memory; When it is detected that the number of rewrites for each area has reached a limit, the memory operation is transferred from one area to another using means for transferring from one area to another area. A data storage system using a non-volatile memory tube is provided.

〔Example〕

The operating principle of the data storage system using non-volatile memory tubes according to the present invention will be described with reference to FIG. Figure 1 shows the data storage status of S and RAM in a non-volatile random access memory consisting of E''FROM and S and RAM. Hnl, area 2, ... area 1 (as an example, 1=10)? 1 area 1 consists of the store count 1ml at the top and the data part Mal at the bottom.Area 凰The same applies to 2~Mal.w1
The number 0 shown on the left side of the diagram. l.

2...10 is 8. Please give me the RAM address.

As the initial storage state, rlJ' is set to the area specifying pointer.
f-, store number count l&LJ of area P&Ll is ``
Write lJ to the data tube to be stored in 1 ml of the data portion of the 1 ml area, and write "0" to all other areas. "l" in the area designation pointer indicates that the data is written in area Nll, and "l" in the count tal indicates that the data is written in area Nll.
” indicates that the number of writes is once, and the data in the S RAM stored as described above is
E''PROMh is moved and stored by a store signal from an external circuit.

Next, to change the data in E"FROM that is in such a storage state, 19. Increase the RAM store count Wolf by 1, change the data in the data portion ml of area NILl, and move it to E2PROM. At this time, the data in areas other than S, the store count ml in area l of RAM, and the data area Nil are not changed.Therefore, the data in E2FROM in the area corresponding to these is not changed. The above-mentioned operations are performed one after another in this way.

S, the number of stores in the RAM area mi increases,
When the limit number of times n is reached When data is changed the next time after reaching the limit number of times n, S, RAM area WL1 is no longer used, and area N12'r is used. Pointer for? Change from rlJ to "2",
Store count of area N12 Ugly 2'i) r OJ
8. to "1" and write data to the data portion 1a2. Move the data in RAM to E''FROM and store it.

After the number of stores F in the area Ha2 reaches the limit number n, use of the area 813 is started ◎Similarly, area part 3, area part 4......Move to use of area N[Li By doing this, the number of rewrites for each bit of E"FROM is limited to the limit number n, while E"FR
The number of rewrites of OM is increased by nX14. Of course, the value of nXi cannot exceed the value of N.

Note that during the above operation, S, RAMt or E”F
When using or changing the data stored in the ROM, first check the area designating pointer to fully detect which area is currently being used.

In an embodiment of the invention, an E of the form shown in FIG.
! The principles of the present invention described above are applied to a nonvolatile random access memory consisting of FROM, S, and RAM. E
The limit number of rewrites per pit in 2PROM and isRAM (n+ is smaller than the limit number N of stores).For multiple areas (ml, m2...NILl) provided in E2FROM or S, RAM , a means is provided for detecting that the limit number of times (n) has been reached for each area.Also, in 71c, a memory operation is performed from one area to another (for example, from area NQI to area m2).
Based on 0 or more provided with means for transitioning (to),
When it is detected that the number of rewrites per area has reached the limit, the memory operation is changed from one area to another (
For example, from area ml to area 2)
An example flowchart of the operation for RO is shown in Figure 11E2. First, in the sterib SOI, step Sll is performed in response to the p determination result of determining the content of the pointer at the address O1 of S and RAM being either 1, 2, . . . , ]0.

S12. ...Proceed to one of the 5 JOIs. For example, when the determination result is 1, this indicates that the data is stored in the area la1, and in step SIX the data at addresses 2 to 10 in the area 11L1 is rewritten. Next, in step 812, the number of stores of address l in area l is counted by 1ali+1. Then, in step 813, a store signal is input, and S, R
Transfer AM data to E”FROM 0 then step 8
14, S, whether the store count of address l in area l of RAM has reached n? judge. If n has not yet been reached, return; if n has been reached, proceed to step SO2; S, RAM address 0 pointer? +IL, advance the area to be used from area mi to area section 2; Next, in step 803, S determines whether the pointer at address 0 in the RAM has exceeded 10. If it still exceeds 1G'lj-, return and return l.
If it exceeds O, the process advances to step S05 and an alarm is displayed.

In the data storage system according to the present invention as shown in FIGS. 1 and 3, when the amount of data to be stored is small compared to the capacity of the nonvolatile random access memory, E"FROM The number of times the E2PROM can be rewritten is set to nX while the maximum number of rewrites of each bit of
1 (where i is the number of S, RAM or E2FROM regions). in this case,
Regarding the limit number N of stores from S, RAM to E2PROM, the condition N≧nXi exists. [Effects of the Invention] According to the present invention, for a nonvolatile memory consisting of a combination of E2FROM and S, RAM, The number of livestock changes is increased and % E” F ROM and S, RA
It is possible to improve the usability of a nonvolatile memory made up of M combinations.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the operating principle of a data storage system using non-volatile memory according to the present invention, γ2 diagram is a diagram showing the operation flow for S, RAM or E2FROM in the second embodiment of the present invention, and FIG. The diagram shows S, RAM and E 2F
Non-volatile random access system consisting of a combination of ROMs
The memory is -rd. Figure 1

Claims (1)

[Claims] Non-volatile random access memory with predetermined limits on the number of stores and the number of rewrites per bit, comprising static random access memory and electrically erasable programmable read. , only
consisting of a memory in which the limit number of bit-by-bit rewrites is smaller than the limit number of stores; the limit number of times is reached for each area of multiple areas provided in the non-volatile random access memory; When it is detected that the number of rewrites for each area has reached the limit number, the memory operation is performed using means for detecting that the memory operation has been performed from one area to another area; A data storage system using non-volatile memory characterized in that it can be migrated from one area to another.