JPH0370056A - Self-diagnostic device for rom - Google Patents

Abstract

PURPOSE:To exactly and surely execute a check and to improve the reliability of a computer system by successively reading out the internal data of a ROM, adding the read data and executing a self-diagnosis part, which decides whether the internal data are normal or abnormal, according to an addition result by a hardware. CONSTITUTION:When a control means 165 is turned to a check mode, a computer system 10 is held in a reset mode. An address generating means 162 successively designate addresses from the initial address to the final address of a ROM 11 with the operation of the control means 165 and the internal data, which are read out from the ROM 11 by this address designation, are added by an adding means 164. In the control means 165, this addition result is compared with a value determined in advance and it is decided whether the internal data of the ROM 11 are normal or abnormal. Thus, the internal data of the ROM 11 can be checked in the manner to the hardware and the internal data can be exactly and surely checked.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a ROM self-diagnosis device of a computer system used for controlling computer-related devices and other electrical equipment, and an object thereof is to be able to reliably check the internal data of the ROM. address generating means for sequentially specifying addresses of a ROM constituting a computer system from an initial address to a final address; and an adding means for adding internal data read out from the ROM when addressed by the address generating means. , controls the address generating means and the adding means, puts the computer system in the reset mode when in the ROM check mode, and calculates the R from the addition result of the adding means.
and a control means for determining whether the OM is normal or abnormal.

(Industrial Application Field) The present invention relates to a ROM (Re) of a computer system used for controlling computer-related devices and other electrical equipment.
The present invention relates to a self-diagnosis device (ad only memory), and particularly to a self-diagnosis device that checks whether data stored in a ROM is correct.

[Conventional technology]

In electrical equipment with a built-in computer system, is the computer system IJ? A program for wholesale is usually stored in a ROM.

In addition, in order to improve the reliability of the operation of electrical equipment that incorporates such a computer system, or from the perspective of needing to know about failures, it is desirable to be able to self-diagnose whether the internal data in the ROM is stored correctly. It will be done.

Conventionally, such a ROM self-diagnosis method involves storing a self-diagnosis program in the ROM and executing this program on a microprocessor.
It determines whether internal data is normal or abnormal.

The most typical diagnostic method using a program is the thumb check method. In the case of an 8-bit ROM, this is done by sequentially reading out the data in the ROM from address O to the final address under program control, adding the read data one byte at a time, and adding all the contents. The value of the lower 16 bits of the result is compared with a preset value, and based on the comparison result, it is determined whether the internal data of the ROM is corrupted or incorrect.

[Problem to be solved by the invention]

However, in the conventional ROM diagnostic method as described above, the program for the thumb check is stored in the ROM, so the internal data of the ROM can only be checked if the program for the check is normal. However, if the program for checking is abnormal, there is a problem in that accurate data checking of the ROM cannot be performed.

The present invention has been made in view of the above points, and is a ROM
An object of the present invention is to provide a ROM self-diagnosis device that can reliably check the internal data of a ROM.

[Means to solve the problem]

A ROM self-diagnosis device according to the present invention includes an address generating means for sequentially specifying addresses of a ROM constituting a computer system from an initial address to a final address;
Adding means for adding internal data read from M;
control means that controls the address generation means and the addition means, puts the computer system in a reset mode when the ROM is in a check mode, and determines whether the ROM is normal or abnormal based on the addition result of the addition means; It is what it is.

[For production]

Once the control means is in check mode, the computer system is held in reset mode. As the control means operates, the address generating means sequentially addresses the ROM from the initial address to the final address, and the internal data read from the ROM by this addressing is added by the adding means. By comparing this addition result with a predetermined value in the control means, it is determined whether the internal data of the ROM is normal or abnormal.

Therefore, in the present invention, by checking the internal data of the ROM using hardware, the internal data can be checked accurately and reliably.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is an overall configuration diagram showing an embodiment of a ROM self-diagnosis device according to the present invention.

In the figure, a computer system used to control electrical equipment includes a central processing unit (hereinafter referred to as CPU) 10 and a program memory (hereinafter referred to as ROM) 11, as is well known.
, data memory (hereinafter referred to as RAM) 12 and CPU1
0 and an input/output interface 13 for exchanging data between the CPU 10 and an external device.
The RAM 12 and the input/output interface 13 are connected by an address bus 14 and a data bus 15.

Further, in FIG. 1, a self-diagnosis section indicated by the general reference numeral 16 is for checking the internal data of the ROM 11 of the computer system in terms of hardware.

The ROM II self-diagnosis section 16 is connected to the ROM 11 via an address bus 161 and connected to an address generation circuit 162 that sequentially specifies the address of the ROM II from address O to the final address, and to the ROMI 1 via a data bus 163. , an 8-bit adder 164 that sequentially adds internal data read from ROMII every time an address is specified by the address generation circuit 161, and an operation timing command is sent to the address generation circuit 162 and the adder 164. At the same time, a read command is given to the ROMII, and based on the result of addition up to the final address of the ROMII by the adder 164, the internal data of the ROM11 is determined to be normal.
It is comprised of a control circuit 165 that compares and determines abnormalities.

Next, the operation of this embodiment configured as described above will be explained.

First, when the power-on reset signal to the control circuit 165 is OFF, the control circuit 165 is set to an active state, thereby outputting a reset signal to the CPU10 to maintain the CPU10 in the OFF or F state. When the control circuit 165 outputs an operation timing command (clock) CLK to the address generation circuit 162, the address generation circuit 162 outputs an address signal. This address signal is updated every time an operation timing command is received from the control circuit 165, thereby specifying the address of the ROM II from address O to the final address.

The address signal is sent to the ROMII via the address bus 161.
When added to ROMII, the address of the ROMII where the data is stored is specified, and based on the read command signal 165a output from the control circuit 165, the data of the specified ROMII is read out and added in 8-bit units via the data bus 163. 164. Adder 164
Then, according to the timing command 165a from the control circuit 165, the data sequentially read from the ROM II for each address specification is sequentially added up to the final address. At this time,
Overflow that occurs due to addition is ignored.

When the internal data of the ROMII is added up to the final address by the adder 164, the addition result is taken into the control circuit 165 and compared with a preset value to determine whether the internal data of the ROMII is normal or abnormal. Note that the setting values to be compared are stored in advance in an empty area of the ROM 11.

If the above comparison result is normal, the control circuit 165
Cancels the reset to PUl0. When it is determined that there is an abnormality, the control circuit 165 outputs an abnormality signal 165C, which activates a lamp or buzzer (not shown) to inform the operator that the ROM 1l is abnormal.

In this embodiment as described above, since the internal data of the ROMII can be checked by hardware using the self-diagnosis section 16 of the hardware configuration, the thumbnail data for checking processing by the CPU10 of the computer system can be changed from the conventional system. The check program is no longer required, so the ROMII
This solves the problem of not being able to accurately check the internal data of the ROM due to an abnormality in the thumb check program even though the internal data of the computer is normal. reliability can be improved.

In the above embodiment, a computer system having one ROM has been described, but a single self-diagnosis section can also perform a data check on a computer system incorporating a plurality of ROMs. In this case, a switching means may be added to the self-diagnosis section of the above embodiment, and each ROM may be switched and connected to a single self-diagnosis section by this switching means.

〔Effect of the invention〕

As explained above, according to the present invention, the internal data of the ROM is sequentially read and added, and the self-diagnosis section that determines whether the internal data is normal or abnormal based on the addition result is configured to be performed by hardware. Checking internal data becomes accurate and reliable, improving the reliability of the computer system.

[Brief explanation of drawings]

FIG. 1 shows the entire configuration of an embodiment of a ROM self-diagnosis device according to the present invention. In the figure, 10 is a CPU, 11 is a ROM, 16 is a self-diagnosis section, 162 is an address generation circuit, 164 is an adder, and 165 is a control circuit.

Claims (1)

[Claims] (1) In a computer system that controls electrical appliances, an address generating means for sequentially specifying an address of a ROM constituting the computer system from an initial address to a final address; an addition means for adding internal data to be read; and controlling the address generation means and the addition means, putting the computer system in a reset mode when the ROM is in a check mode, and determining whether the ROM is normal based on the addition result of the addition means. A self-diagnosis device for a ROM, comprising: a control means for determining an abnormality; and a control means for determining an abnormality.