JPH10228787A - Input/output module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occurrence of abnormal writing and reading of a non- volatile storage circuit by switching an object of writing operation to the other data region successively and processing them when the number of times of writing exceeds or a writing error occurs in one data region. SOLUTION: When the number of times of writing in a data region is within a limit, a control circuit 1a writes data in a data region of a selected partition, when the number of times of writing exceeds the limit or a writing error occurs, it is retrieved whether a usable partition exists or not in a non-volatile storage circuit 2. When it exists, contents of partition control region are rewritten so that a usable partition is selected. Also, When the number of times of writing exceeds the limit or a writing error occurs at the time of writing operation, an object of writing operation is successively rewritten to the prescribed partition and the like and processed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input / output module used in a distributed control device, and more particularly, to an EEPROM (Electrically Erasable Programmable Programmable Programmable Program) in the input / output module.
The present invention relates to an input / output module that reduces the occurrence of write errors and read errors in a nonvolatile storage circuit such as an capable ROM.

[0002]

2. Description of the Related Art A conventional input / output module is mounted on a distributed controller and exchanges data with external devices. For example, consider an input / output module that communicates with an external device via a field bus.

FIG. 4 is a block diagram showing an example of such a conventional input / output module. In FIG. 4, reference numeral 1 denotes a control circuit such as a CPU (Central Processing Unit);
Is a nonvolatile storage circuit such as an EEPROM, 3 is an interface circuit with a distributed control device, 4 is an interface circuit with a field bus, and 100 and 101 are input / output signals from the distributed control device and the field bus.

An input / output signal 100 from the distributed control device is connected to the interface circuit 3, and the input / output of the interface circuit 3 is connected to the control circuit 1.

On the other hand, an input signal 10 from the field bus
1 is connected to the interface circuit 4, and inputs and outputs from the interface circuit 4 are connected to the control circuit 1. Further, input / output from the nonvolatile storage circuit 2 is also connected to the control circuit 1.

Here, the operation of the conventional example shown in FIG. 4 will be described. In the non-volatile storage circuit 2, setting conditions necessary for the operation of the input / output module itself, information on the distributed control device side, information necessary for communication with the field bus such as a device configuration connected to the field bus, and the like are stored in the higher order. Stored from a distributed controller.

Further, since the nonvolatile memory circuit 2 can retain the stored information even if the power supply voltage is lost due to the power OFF of the distributed control device or the like, the work of detaching the input / output module from the distributed control device can be performed. Also do not lose stored information.

For example, an input / output signal 1 from a distributed control device
When 00 is input to the control circuit 1 via the interface circuit 3, the control circuit 1 generates a transmission signal based on the signal in accordance with a signal format and transmission procedure suitable for the field bus, and inputs and outputs the transmission signal via the interface circuit 4. Signal 1
01 is supplied to the field bus.

In the transmission signal generation processing, the setting conditions in the nonvolatile storage circuit 2, information necessary for communication with the field bus, and the like are sequentially read out and processed.

The distributed controller rewrites data in the nonvolatile memory circuit 2 as necessary, for example, when the configuration of a device connected to the field bus is changed.

As a result, input / output processing between the distributed control device and the field bus can be performed based on the information stored in the nonvolatile storage circuit 2.

[0012]

However, the nonvolatile memory circuit 2 generally has a limit on the number of times of writing. If the number of times of writing exceeds the limit, the possibility of abnormal writing or reading increases.

In the conventional example shown in FIG. 4, there is a problem that if a write error or a read error of the nonvolatile memory circuit 2 occurs, the operation itself of the input / output module and the communication with the field bus will fail. was there.
Accordingly, an object of the present invention is to realize an input / output module that can reduce the occurrence of a write error and a read error in a nonvolatile memory circuit.

[0014]

In order to achieve the above object, according to a first aspect of the present invention, there is provided an input / output module having a nonvolatile memory circuit therein for use in a distributed control device. Two interface circuits for exchanging data with an external device, the non-volatile storage circuit provided with a plurality of data areas, and controlling the two interface circuits and exceeding the number of write times or a write error in one of the data areas And a control circuit for sequentially switching the target of the write operation to another data area when the occurrence of the error occurs.

In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the nonvolatile memory circuit includes a plurality of data areas and a number of times of writing to the plurality of data areas. It is characterized by comprising a data management area to be stored and a partition management area to store information of the data area to be written.

In order to achieve the above object, a third aspect of the present invention is characterized in that in the first aspect of the present invention, the nonvolatile memory circuit is an EEPROM.

In order to achieve the above object, a fourth aspect of the present invention is characterized in that, in the first aspect of the present invention, the nonvolatile memory circuit is a flash memory.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration block diagram showing one embodiment of an input / output module according to the present invention.

In FIG. 1, 2, 3, 4, 100 and 10
Reference numeral 1 denotes the same reference numeral as in FIG. 4, and reference numeral 1a denotes a control circuit. The connection relationship is almost the same as that of FIG.

The operation of the embodiment shown in FIG. 1 will be described with reference to FIGS. FIG. 2 is an explanatory diagram showing a configuration of a storage area in the nonvolatile memory circuit 2, and FIG. 3 is a flowchart illustrating an operation of the embodiment.

As shown in FIG. 2, the non-volatile memory circuit 2 has four memory cells as shown by "a", "b", "c" and "d" in FIG.
The area indicated by "a" in FIG. 2 is a nonvolatile memory circuit management area, and the areas "b", "c", and "d" in FIG. 2 are data segments.

Information such as the number of data segments and the size of data segments is stored in the nonvolatile memory circuit management area indicated by "A" in FIG.

On the other hand, the three data segments indicated by "b", "c" and "d" in FIG. 2 have the same configuration, and the individual data segments are further referred to as "e" and "e" in FIG.
It is divided into four as shown by "f", "g" and "h".

In FIG. 2, "e" is a partition management area,
"F", "G", and "H" in FIG. 2 are partitions. The partition management area stores information on the currently used partition.

Further, "f", "g" and "h" in FIG.
The partition shown in FIG. 2 is divided into a data management area shown by "R" in FIG. 2 and a data area shown by "NU" in FIG. The number of times of writing to the data area of the corresponding partition is stored in the data management area indicated by “R” in FIG.

Next, an actual write operation will be described with reference to FIG. When the write operation to the nonvolatile storage circuit 2 starts, the control circuit 1a reads the data management area of the selected partition based on the information stored in the partition management area, as shown in FIG.

Then, as shown in FIG. 3B, the control circuit 1a determines whether or not the number of times of writing to the data area stored in the data management area exceeds a writing limit.

If the number of times of writing to the data area does not exceed the writing limit, the control circuit 1a writes data to the data area of the selected partition as shown in FIG. As shown in d), it is determined whether or not a write error has occurred. If no write error has occurred, the write operation ends normally.

On the other hand, when the number of times of writing to the data area exceeds the write limit in FIG. 3B, or when a write error occurs in FIG. 3D, as shown in FIG. Then, the control circuit 1a searches the nonvolatile memory circuit 2 to see if there is a usable partition.

In FIG. 3E, if there is a usable partition, the control circuit 1a changes the contents of the partition management area so that the usable partition is selected as shown in FIG. 3F. At the same time, the process shown in FIG. 3A is performed.

If there is no usable partition in FIG. 3E, the operation of the input / output module will fail, so that the input / output module is disabled as shown in FIG. 3G. The write operation ends abnormally.

For example, in FIG.
In the case of the partition indicated by "f", if the number of times of writing is exceeded or a writing error occurs during the writing operation, the control circuit 1a sets the target of the writing operation to "g" in FIG.
The processing is switched to the partition shown in FIG.

Similarly, when the number of times of writing or the writing error occurs during the writing operation in the partition indicated by "g" in FIG.
The target of the write operation is sequentially switched to the partition shown in the middle "h" and the processing is performed.

When the number of times of writing is exceeded or a writing error occurs in one data area provided with a plurality of data areas, the target of the writing operation is sequentially switched to another data area to perform processing. Thus, the number of times that data can be written to the nonvolatile memory circuit 2 substantially increases. In other words, it is possible to extend the life of the input / output module.

As a result, when the number of times of writing is exceeded or a writing error occurs in one data area provided with a plurality of data areas, the target of the writing operation is sequentially switched to another data area to perform processing. This makes it possible to reduce the occurrence of write errors and read errors in the nonvolatile memory circuit 2.

In the embodiment and the like shown in FIG. 1, the input / output module used in the distributed control device is illustrated, but the present invention can be applied to other devices using a nonvolatile memory circuit.

As for the configuration in the nonvolatile memory circuit 2, the same number of data management areas are provided for a plurality of data areas as shown in FIG. The number of times may be managed collectively.

Further, an apparatus having a limited number of times of writing,
It is easy to apply the present invention to memory management or the like of a device that wants to avoid a writing error or the like.

As a nonvolatile memory circuit, EEPR
Although the OM is exemplified, a flash memory or the like having a limited number of times of writing may be used.

Although the limit of the number of times of writing is used as the criterion of the number of times of writing, the present invention is not limited to this.
It is possible to further improve the reliability.

[0041]

As is apparent from the above description,
According to the present invention, the following effects can be obtained. When a plurality of data areas are provided, when the number of times of writing is exceeded or a writing error occurs in one of the data areas, a write operation target is sequentially switched to another data area and the processing is performed, so that a writing error of the nonvolatile memory circuit is performed. In addition, an input / output module capable of reducing the occurrence of read errors can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing one embodiment of an input / output module according to the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a storage area in a nonvolatile storage circuit.

FIG. 3 is a flowchart illustrating the operation of the embodiment.

FIG. 4 is a configuration block diagram illustrating an example of a conventional input / output module.

[Explanation of symbols]

 1, 1a control circuit 2 nonvolatile memory circuit 3, 4 interface circuit 100, 101 input / output signal

Claims (4)

[Claims] 1. An input / output module used in a distributed control device and having a nonvolatile memory circuit therein, comprising: two interface circuits for exchanging data with the distributed control device and an external device; and a plurality of data areas. Controlling the non-volatile storage circuit and the two interface circuits, and sequentially switching the target of a write operation to another data area when one of the data areas has exceeded the number of write operations or a write error, and performing processing. An input / output module comprising a circuit. 2. A nonvolatile memory circuit comprising: a plurality of data areas; a data management area for storing the number of times of writing to the plurality of data areas; and a partition for storing information of the data area to be subjected to a write operation. 2. The input / output module according to claim 1, comprising a management area. 3. The input / output module according to claim 1, wherein said nonvolatile memory circuit is an EEPROM. 4. The input / output module according to claim 1, wherein said nonvolatile storage circuit is a flash memory.