JPH03211639A - Method and device for rewriting data - Google Patents

Abstract

PURPOSE:To shorten the writing time of data and to shorten the occupancy time of a central processing unit (MPU) to rewriting by rewriting only the low-order bytes of data designated with pointer information. CONSTITUTION:RAM 12 previously stores plural pieces of data 12a and 12b whose highest-order bytes are different from each other pointer information 12c at the same number of bytes as the data stored in RAM 11. The data of the highest-order bytes of the data on a counted value when a counting operation by MPU 10 is ended is written into pointer information 12c. Data on a medium-order byte and the low-order byte in data 11b in the counted value when the counting operation from RAM 11 is ended, are written in the area of the medium-order byte and the low-order byte in data 12a or 12b, which is shown by pointer information 12c. Thus, the rewriting of the high-order byte of data is eliminated the writing time of data can be shortened and the occupancy time of the central processing unit to writing can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data rewriting method and apparatus for rewriting stored data to desired data.

[Conventional technology]

Conventionally, this type of data rewriting method has been used, for example, in image recording devices, in which the number of sheets of recording paper on which images have been recorded is counted by a central processing unit, etc., and the counter value is sequentially stored in the RAM within the device body. When the image recording is completed, all the counter values at the time of the completion are written from the RAM to the RAM of each unit such as a photoreceptor and a developing section that are removably installed in the apparatus main body, for example, The counter value data in the RAM of each unit was rewritten, and the central processing unit used the rewritten counter value to determine the usage limit of each unit.

[Problem to be solved by the invention]

However, in the data rewriting method described above, when the CPU rewrites the RAM on the unit side, an interval of approximately 1.0 [rns] is required per byte, so in the case of rewriting multiple bytes, There has been a problem in that the exclusive time of the CPU becomes long, causing a negative effect such as a delay in controlling other operations by the CPU.

The present invention has been made in view of the above problems, and is a data rewrite that simplifies the data rewriting work and shortens the data writing time, thereby reducing the exclusive time of the central processing unit for the rewriting. The task is to provide a method.

[Means to solve the problem]

In the present invention, in a first storage means such as a RAM of a unit, at least two counter values having a predetermined number of bytes and having different upper bytes and pointer information for specifying desired data from among the data are stored in advance. At the same time, the first data consisting of a predetermined number of bytes before the write instruction is stored in a second storage means such as a RAM in the device main body, and the central processing unit or the like stores the second data in response to the predetermined write instruction. Second data consisting of a predetermined number of bytes, such as a counter value of the number of recorded sheets, is written in the storage means, and the second data is written in the storage means, and the second data is written in the storage means, and the second data, such as a counter value of the number of recorded sheets, is written in the storage means, and the second data is written in the storage means, and the second data is written in the storage means. The content of the pointer information is rewritten to the upper byte of the second data, and the lower byte of the second data stored in the second storage means is rewritten to the first storage means specified by the pointer information. It is characterized by writing to the lower byte of data.

[Effect]

If the upper byte of the first data and the upper byte of the second data have changed, the contents of the pointer information will be changed to the second data.
, and only the lower byte of the data in the first storage means specified by the pointer information is rewritten without rewriting all the data stored in the first storage means.

Therefore, it becomes unnecessary to rewrite the upper byte of the data stored in the first storage means, and the rewriting of the data can be completed using only the time required to rewrite the lower byte.

〔Example〕

Embodiments of the present invention will be described in detail based on the drawings of FIGS. 1 and 2.

FIG. 1 is a block diagram showing a schematic configuration of a data rewriting device according to the present invention. In addition, in this example,
A case where the data rewriting device described above is used in an image recording device will be explained.

In the figure, a central processing unit (hereinafter referred to as rMPUJ) is shown.

) 10 and RAMI 1 are arranged in the main body of the image recording apparatus (not shown), and the MPU10 counts the number of sheets of recording paper on which an image has been recorded, and the counter value is set as R.
, AMll, and when the image recording is completed, all the counter values at the time of the completion are stored in the RAMI.
1, data is written into the RAM 12, 13 of each unit such as a photoreceptor and a developing section that are detachably mounted in the apparatus main body, and the counter value data in the RAM of each unit is rewritten.

RAMII stores the counter value data lla when the MPUl0 starts counting, and the counter value data llb that are sequentially input until the counting ends.
For example, each data is stored as 3-byte data consisting of the most significant byte, middle byte, and lower byte.

The RAMs 12 and 13 have the same configuration, and for convenience of explanation, only the RAM 12 will be described here. RAM1
2 is stored in the RAM II.

A plurality of data having the same number of bytes as the 3-byte data, but different in the most significant byte, for example, data 12a in which the most significant byte is set to two types, "00" and "01". , 12b are stored in advance, and pointer information 12c for specifying desired data from among the data each having a 3-byte configuration is also stored in advance.The data 12 stored in advance in the RAM 12
The middle byte and lower byte data of a112b may be any data, and the content of the pointer information 12c is M
The most significant/<ite data of the counter value data when the counting operation by PUl0 is completed is written.

The middle byte and lower byte data of the counter value data 11b at the end of the counting operation read from RAMII by MPUl0 are the predetermined data (data 12a or 12b) corresponding middle and lower bytes! Written in the Kuito area.

Next, the data rewriting operation will be explained in detail based on the flowchart of FIG.

When the MPU10 finishes counting the number of recording sheets, it is determined that the counting operation has ended, that is, a write instruction has been issued, and in FIG. It is determined from the counter value data llb whether there is a change in the most significant byte data of the counter value (step 101).

Here, if there is a change in the most significant byte of the counter value, the pointer information 12C in the RAM 12 is rewritten to the changed most significant byte data (step 102).
, Next, it is determined whether there is a change in the middle byte of the counter value (step 103). If there is no change in the most significant byte of the counter value, the process directly proceeds to step 103 to determine whether the middle byte has changed.

Here, if there is a change in the middle byte of the counter value, the data of the middle byte of the changed counter value is added to the counter value data (data 12a or 12b) in the RAM 12 indicated by the pointer information 12c. Write to the corresponding middle byte (step 104), and write the data of the lower byte of the changed middle byte to the corresponding data of the counter value in the RAM 12 (data 12a or 12b) indicated by the pointer information 12c. The data is written to the lower byte (step 106), and the above rewriting operation is completed. Further, if there is no change in the middle byte of the counter value in step 103, it is then determined whether there is a change in the lower byte of the counter value (step 10
5).

Here, if there is no change in the lower byte of the counter value, the above operation is ended without performing the data rewriting operation, and if there is a change in the lower byte of the counter value, the process proceeds to step 106. , writes the lower byte of the changed counter value into the corresponding lower byte of the counter value data (data 12a or 12b) in the RAM 12 indicated by the pointer information 12c, and ends the data rewriting operation.

Therefore, in the present invention, a plurality of counter value data having different most significant bytes are stored in advance in the memory to be rewritten, and the data of the lower byte of the counter value at the end of counting is transferred to the above data indicated by the pointer information. Since it is possible to write to the corresponding lower byte area of the predetermined data (data 12a or 12b) in the memory,
There is no need to rewrite the upper byte, and the rewriting of the data can be completed using only the time required to rewrite the lower byte.

In this embodiment, data lla of the counter value at the start of counting and data llb of the counter value at the end of counting are stored in RAMI 1, and the most significant byte, middle and lower byte are extracted from each of the above data. determine changes,
Although the pointer information in the RAM 12 and the middle and lower bytes of the counter value data are rewritten in accordance with the above judgment, the present invention is not limited to this. For example, only changes in the most significant byte of RAM II are judged, and the above judgment RAM12 depending on
It is also possible to rewrite the pointer information and the middle and lower bytes of the counter value data. Further, in the embodiment, the case where the number of recording sheets is counted using an image recording device and the stored data is rewritten to the counter value has been described as an example, but the present invention is not limited to this, and the present invention can be applied to a certain number of recording sheets. It can also be applied to rewriting data that changes, such as time, and can also be used in devices other than image recording devices. Furthermore, in the embodiment, rewriting of 3 bytes of data was explained, but
It goes without saying that the present invention can also be used to rewrite data of other numbers of bytes.

〔Effect of the invention〕

As explained above, in the present invention, only the lower byte of the data in the storage means specified by the pointer information can be rewritten without rewriting all the data stored in the storage means. It is possible to simplify the work and shorten the writing time of the data, thereby shortening the exclusive time of the central processing unit for the rewriting.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a data rewriting device according to the present invention, and FIG. 2 is a flowchart for explaining a data rewriting operation by the data rewriting device shown in FIG. 10...Central processing unit (MPU), 11...Main body side RAM, 12.13-...Unit side RAM, lla
. 11 b, 12 a, 12 b---force'y
9 value (7) 9.12c... Pointer information. Figure 1

Claims (4)

[Claims] (1) At least two pieces of data consisting of a predetermined number of bytes and having different upper bytes and pointer information for specifying desired data from among the data are stored in advance in a first storage means, and a second storage means is stored in advance. Pre-store first data consisting of a predetermined number of bytes before a write instruction in the means, writing second data consisting of a predetermined number of bytes in the second storage means in response to a predetermined write instruction, rewriting the pointer information to the upper byte of the second data according to a change between the upper byte of the first data and the upper byte of the second data; A data rewriting method characterized by writing to a lower byte of data in the first storage means specified by pointer information. (2) At least two pieces of data consisting of a predetermined number of bytes and having different upper bytes and pointer information for specifying desired data from among the data are stored in advance in the first storage means, and the second storage means Pre-store first data consisting of a predetermined number of bytes before a write instruction in the means, writing second data consisting of a predetermined number of bytes in the second storage means in response to a predetermined write instruction, rewriting the pointer information to the upper byte of the second data according to a change between the upper byte of the first data and the upper byte of the second data; and the lower byte of the stored first data. and the lower byte of the second data, the lower byte of the second data is written into the lower byte of the data in the first storage means specified by the pointer information. How to rewrite data. (3) a first storage means for storing in advance at least two pieces of data consisting of a predetermined number of bytes and having different upper bytes and pointer information for specifying desired data from the data; and an instruction means for instructing data writing. and a first data consisting of a predetermined number of bytes before the write instruction, and a second data consisting of a predetermined number of bytes in accordance with the write instruction.
a second storage means for storing the data; a detection means for detecting a change between the upper byte of the stored first data and the upper byte of the second data; and byte writing means for rewriting the pointer information into the upper byte of the second data and writing the lower byte of the second data into the lower byte of the data in the first storage means specified by the pointer information. A data rewriting device characterized by: (4) a first storage means for storing in advance at least two pieces of data each having a predetermined number of bytes and having different upper bytes and pointer information for specifying desired data from among the data; and an instruction means for instructing data writing. and a first data consisting of a predetermined number of bytes before the write instruction, and a second data consisting of a predetermined number of bytes in accordance with the write instruction.
a second storage means for storing the stored data; a first detection means for detecting a change between the upper byte of the stored first data and the upper byte of the second data; a second detection means for detecting a change between a lower byte of the first data and a lower byte of the second data; and in response to the detection by the first detection means, the pointer information is transferred to the second data. Byte writing means for writing the lower byte of the second data into the lower byte of the data in the first storage means designated by the pointer information in response to detection by the second detection means. A data rewriting device characterized by comprising: