JPH0612339A - Memory check method - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize a memory check method that enables detection of a defective memory by a single initial check even when a large capacity and a large number of data memories are used. [Configuration] The microcomputer 201 writes and reads a value such as “FF” or “OO” over the entire area of the data memory 202, and checks whether the written value and the read value are equal. If there is a defective memory, the written value and the read value will not match. When a mismatch occurs, the microcomputer stores the address in the dedicated register 208 and further sets the register 209 indicating that the mismatch has occurred. Then, the microcomputer checks the next address. When the check of all areas is completed, the microcomputer 201 displays the mismatch of the values in the memory to the outside and stops the system operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of checking a memory in a microcomputer system, and more particularly to a method of detecting a failure of the memory and notifying it to the outside.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration example of a conventional microcomputer system. This system consists of the following elements or circuits.

A microcomputer (hereinafter abbreviated as "microcomputer") 201 for performing arithmetic processing.

A readable / writable data memory 20 for storing data for arithmetic processing of the microcomputer 201.
2.

An address decoder 203 for generating a memory selection signal 207.

An input / output circuit 204 for displaying the operating state to the outside and for setting the state from the outside.

An internal bus 205 that connects the elements or circuits.

The data memory 202 includes a microcomputer 201.
The instructions and data necessary for the processing of the microcomputer system are stored. Therefore, the memory circuit is required to have high reliability. Therefore, the initial check of the data memory 202 is usually performed at the start of the operation of the microcomputer system. FIG. 4 shows the procedure of the initial check processing of the memory in the conventional method. In other words, the microcomputer 201 is "FF" over the entire area of the data memory 202
Writing and reading of test data such as or "OO" is executed, and it is checked whether the written value is equal to the read value. When a memory failure occurs, the written value and the read value do not match, so the microcomputer 2
In 01, after the failure of the memory was displayed to the outside through the input / output circuit 204, the operation of the system was stopped.

[0009]

However, the conventional processing procedure is premised on that a memory failure is an extremely rare phenomenon. Therefore, there is no problem even if the memory failure is displayed to the outside immediately after the memory failure occurs and the system is stopped. However, as the number of bits in one memory increases, the probability of memory failure increasing. Moreover, as the processing capacity of the microcomputer is improved, the amount of data required is also increasing. for that reason,
In a microcomputer system having a large capacity and using a large number of memories, there is a high possibility that a plurality of memories will simultaneously fail. In such a state, at the time of the initial check at the start of system operation, if the system is stopped due to a single memory failure, even if the memory in which the failure was detected for the first time is replaced, In another memory, a mismatch between the written value and the read value will occur. Therefore, it takes a considerable time for the system to become normal.

An object of the present invention is to solve the above-mentioned problems and to make it possible to detect all defective memories by a single initial check even when a large capacity and a large number of data memories are used. It is to realize the memory check method.

[0011]

The gist of the present invention is to immediately stop the operation even if the written value and the read value do not match at the time of the initial check of the data memory at the start of the operation of the system. Instead, set the register that indicates that a mismatch has occurred, store the address where a mismatch has occurred in a dedicated register, move to the next address check, and check the entire memory area. There is a change in the processing procedure.

That is, the above object of the present invention is to provide a value written by the microcomputer in the initial check of the data memory executed at the start of the operation of the microcomputer system including the microcomputer, the data memory and other peripheral circuits. If a mismatch occurs in the read values, record the address where the mismatch occurred,
This is achieved by a memory check method characterized by notifying the occurrence of a mismatch and its address to the outside after performing all the checks of the data memory that is the target of the initial check.

[0013]

FIG. 2 shows an example of the configuration of a microcomputer system according to the present invention. In addition to the conventional system, a register 208 for recording the address when a data mismatch occurs and a register 209 for indicating that a mismatch has occurred are added.

FIG. 1 shows an embodiment of the procedure of the initial check processing of the memory according to the present invention. That is, the data memory 2
The microcomputer 201 writes and reads a value such as "FF" or "OO" over the entire area 02, and checks whether the written value and the read value are equal. If there is a defective memory, the written value and the read value will not match. When a mismatch occurs, the microcomputer stores the address in the dedicated register 208 and further sets the register 209 indicating that the mismatch has occurred. Then, the microcomputer checks the next address. When the check of all areas is completed, the microcomputer 201 displays the mismatch of the values in the memory to the outside and stops the system operation.

[0015]

According to the present invention, even if there are a plurality of defective data memories in the system, all abnormal memories can be identified by a single initial check.

[Brief description of drawings]

FIG. 1 shows a processing procedure of a memory check method according to the present invention.

FIG. 2 shows an internal configuration example of an embodiment of a microcomputer system according to the present invention.

FIG. 3 shows an example of an internal configuration of an example of a conventional microcomputer system.

FIG. 4 shows a processing procedure of a conventional memory check method.

[Explanation of symbols]

 201 Microcomputer 202 Data memory 203 Address decoder 204 Input / output circuit 205 Internal bus 207 Memory selection signal 208 Mismatch occurrence address register 209 Mismatch occurrence display register

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[Procedure amendment]

[Submission date] February 16, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

According to the present invention, even if there are a plurality of defective data memories in the system, all abnormal memories can be identified by a single initial check.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 shows a processing procedure of a memory check method according to the present invention.

FIG. 2 shows an internal configuration example of an embodiment of a microcomputer system according to the present invention.

FIG. 3 shows an example of an internal configuration of an example of a conventional microcomputer system.

FIG. 4 shows a processing procedure of a conventional memory check method.

[Description of Reference Signs] 201 Microcomputer 202 Data memory 203 Address decoder 204 Input / output circuit 205 Internal bus 207 Memory selection signal 208 Mismatch occurrence address register 209 Mismatch occurrence display register

Claims (1)

[Claims] 1. A mismatch between a value written by a microcomputer and a value read by the microcomputer occurs in an initial check of a data memory executed at the start of operation of a microcomputer system including a microcomputer, a data memory and other peripheral circuits. In this case, the memory check method is characterized in that the address where the mismatch occurs is recorded, all the checks of the data memory subject to the initial check are executed, and then the occurrence of the mismatch and the address are notified to the outside.