JPS63233452A - Data protecting device - Google Patents

Abstract

PURPOSE:To effectively suppress the runaway of a device and to prevent data in a RAM area from being damaged by writing a command jumping to a specified address in an unused area. CONSTITUTION:The command jumping to the specified address (e.g. zero address) is stored in the unused area of a memory 12. Even if runaway is generated, data in the memory area can be prevented from being damaged thereafter. Since the system data may be damaged during the runaway, a system data checking program 21 is executed when the address is returned to zero address by a zero address restoring program 23 at the time of runaway restoration and all data are initialized to correct values.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data protection device included in a microcomputer having a central processing unit (hereinafter referred to as a CPU) and a memory.

For example, today's electronic key telephone devices equipped with microcomputers not only connect to central office lines;
The structure is such that it can perform various additional functions.

In order to make these functions work, the user or the like selects and uses the desired functions by setting predetermined system data. in this case,
If the system data is set using hardware such as dip switches, setting complex system data with dozens or more functions requires the same number of dip switches as the number of functions. The number of switches would be large, making it impossible due to space considerations.

Therefore, the conventional 5 electronic button telephone devices equipped with complicated functions are constructed so that system data for operating the functions is stored in a microcomputer, and the desired functions are performed by setting the system data. There is.

Problems to be Solved by the Invention Incidentally, in such an electronic button telephone device, the CPU
There was no built-in device to protect the recorded system data even if the microcomputer, which has a computer and memory, goes out of control due to external noise, operational error, or the like.

Therefore, if the microcomputer goes out of control, the stored system data will be destroyed, and when the microcomputer returns to normal operation, it will no longer be able to operate normally, and recovery will take a lot of time and money. Ta.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a data protection device that can protect data stored in a memory.

Means for Resolving the Problems In order to achieve the above object, the data protection device of the present invention:
If a command to jump to a specific address is written in an unused area and the same system data is written in three or more locations in the RAM area, the above 3. authentic data determining means for reading and comparing each piece of system data that is older than the previous section and finding the correct data by majority vote; and initializing means for initializing a RAM area with the correct data found by the determining means; It is characterized by having the following.

--- When some microcomputers go out of control, they often jump to an unexpected address, but if a command to jump to a specific address is stored in an unused area of memory, as shown above, the runaway can occur. Even if the program starts, it will always return to a specific address, so runaway behavior can be effectively prevented.

Furthermore, there is a risk that data in the RAM area may be destroyed during a runaway, but in that case, not all data will be destroyed, and in most cases only a portion of the data will be destroyed. Therefore, if you write system data in multiple locations as in the present invention, read all of them, and take a majority vote, you can find undamaged data, and if you initialize with this data, you can protect your data. You can be sure of everything.

大-ノLJL FIG. 1 is a circuit block diagram of an electronic button telephone device equipped with a data protection device as an embodiment of the present invention.
This electronic button telephone device has three central office lines 001 to CO3.
The system consists of eight extension telephones STI to ST8. In the figure, 1 indicates a main device as a simple telephone exchange, 2 is an interface section with the above-mentioned office lines COI to CO3, 3 is a part of the office line control dial sender, and 4 is a CPU and memory which will be described later. 5 is a cross-point control unit; 6 is a tone sound oscillation unit including an oscillation source 6a; and 7 is a cross-point unit.

Of the above configuration, each component except for the system control unit 4 equipped with a data protection device as an embodiment of the present invention is already known and detailed explanation will be omitted.

The system control unit 4 includes a main CPU 1 and a memory 1.
It is composed of a microcomputer consisting of ROM 13 and RAM 14 as 2, and performs various functions such as controlling exchanges between central office lines C01 to CO3 and extension telephones STI to ST8, and mutual exchange control between telephones, for example, regulating outgoing calls. It also performs system functions.

FIG. 2 shows a memory map of the memory 12, in which a system data check program 21 and a normal processing program 22 are stored in the ROM area in order starting from address 0000, and the remaining unused area is A zero address return program 23 is stored. On the other hand, the RAM area contains the same system data A, B, and C.
are written in, for example, three locations 26, 27, and 28.

Then, in the remaining unused area of the RAM area, the same memory as that stored in the unused area of the ROM 13 is stored.
An address return program 23 is stored.

This electronic button telephone device is used in the same way as known ones, but is it system-based? The system data check program 21 stored in the ROM 13 is executed when the 111 section 4 starts up or returns from a runaway state. That is, although the system data stored in the memory is hacked up at the time of startup, the system data check program 21 is executed in order to determine whether the system data has been accurately held when the program is executed. Furthermore, when returning from a runaway, the system data may have been destroyed during the runaway, so when the return to address 0 program 23 returns to address 0,
The system data check program 21 is executed.

The operation of the system data check program 2I will be explained based on the flowchart shown in FIG. First, task T1 reads the first data. The first data is system data A, but this system data A
are also stored in two other locations, 27°2.8, so those system data A are read in task T2. Thereafter, a comparison is made in task T3 to see if all the read system data A are the same. As a result of the comparison, if there is different system data A, step to task T4, take a majority vote on system data A, replace and write the system data A that has the largest amount in all the read locations, and initialize. Let's do it. Then, the program advances to task T5 and determines whether all system data has been checked. If all system data has been checked, this program ends and the function as an electronic button telephone device resumes normal operation. Started automatically. If there is system data left to check,
The process advances from task T5 to task T6, reads the next system data B, and executes tasks T2 to T5. The above operation is repeated for all system data. Note that if all the system data read in task T3 is the same, there is no need to replace the data.
Avoids task T4 and advances to task T5.

As described above, in this embodiment, even if the microcomputer runs out of control into an area that is conventionally unused, it jumps to a specific address in this unused area, which is address O in this embodiment. Since the command is memorized, subsequent destruction of the memory area can be prevented. This is especially effective when running out of control, as it often flies to unused areas. In addition, even if a system data storage location is corrupted, only a small amount of system data will be destroyed, and a large amount of other system data will remain in a normal state. 21, the correct data is found and all data are initialized to correct values.

Note that the number of locations in which the same system data is stored may be stored in at least three locations since the decision is made by majority vote, but it is sufficient to determine the number of locations depending on the configuration state of the system.

In addition, the O address return program 2 stored in the RAM 14
3 was provided at the end of all system data, but the first location 26 and the second location 27, and the second location 27 and 3
It can be easily provided between the system data at point 28.

Furthermore, in the system data check program 21,
Although all the read memory areas were initialized using the system data found by majority vote, R of only the part where different and smaller data was stored was initialized.
It may be configured to initialize the AM area.

Highlights ■ Prevention As mentioned above, in the data protection device of the present invention, a command to jump to a specific address is written in all unused areas of the memory, and the data to be stored is stored in three or more locations. Since the same data is written to
Even in the event of a runaway, the data will be destroyed to a minimum, and other data will be protected.

In addition, the data written in the three or more locations is read and compared, and a majority vote is taken to find the correct data, and the system is initialized with this correct data. Even if it is destroyed, all data is replaced with correct data, so the functions of the microcombiner continue to operate normally.

Furthermore, the microcomputer that incorporates this data protection device does not require any special operations from the outside, so even if the data goes out of control, the data will be automatically restored and the system will remain in its original state. be done.

Therefore, waste of time and money caused by runaway operation is eliminated.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of an electronic button telephone device equipped with a data protection device as an embodiment of the present invention, FIG. 2 is a memory map stored in a memory, and FIG. 3 is a flowchart of the comparison and replacement means. be. DESCRIPTION OF SYMBOLS 1... Main device, 4... System control part, 11... Main CPU, 12... Memory,
Engineering 3...ROM, 14...RAM. 21... System data check program, 23.
...O address return program, 26.27.28...System data. Patent applicant: Sanyo Electric Co., Ltd. Agent: Patent attorney Tsukasa Nakajima Figure 2, Figure 3

Claims (1)

[Claims] (1) Memory in which a command to jump to a specific address is written in an unused area and the same system data is written in three or more locations in the RAM area, and when the microcomputer recovers from a runaway or starts up. , authentic data determination means that reads and compares each system data written in the three or more locations and finds the correct data by majority vote; and R based on the correct data found by the determination means.
A data protection device comprising: initialization means for initializing an AM area;