JPH08220198A - Battery backup memory unit and backup function testing method - Google Patents

Abstract

PURPOSE: To confirm a backup function without interrupting the use of a memory by providing a means for controlling the power supply for two systems of memories having each backup power supply, and a memory checking means, and a setting means. CONSTITUTION: The use of a memory circuit 15 (or 16) cannot be suspended since external memory access can be accepted during the power breaking operation, the read data checking operation, and data copying operation of a backup function test due to the function of a memory access settlement circuit 14. Also, the most recent data can be written into a memory circuit which is not to be tested and the most recent data are written into a memory circuit to be tested excluding the initial certain timing of backup function testing operation, the memory data of both systems can be completely matched by data copy operation. When a test is suspended due to a trouble, the systems are not switched and hence the other system can be used, thus also preventing data from being reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery backup memory unit which retains stored contents even when main power is cut off by backing up a memory with a battery and a backup function test method therefor.

[0002]

2. Description of the Related Art As a battery backup memory unit of this type which has been conventionally used, a structure shown in a block diagram of FIG. 3 is generally adopted. That is,
The battery backup memory unit is composed of a memory circuit 32 having a backup power supply 33 and an interface control circuit 31 for connecting an external memory access to the memory circuit 32. The external memory access is accepted by the interface control circuit 31. And the memory circuit 32 is accessed.

The memory circuit 32 is normally supplied with power from the main power source of the external circuit, but when the power is cut off or the memory unit is disconnected from the external circuit, the memory circuit 32 is automatically switched to the backup power source from the battery of the backup power source. Powered,
Prevents the memory from disappearing.

Normally, the backup function test means of the backup power supply 33 is not provided.

As an example in which the backup function test means is provided, there is a memory unit read / write device disclosed in Japanese Patent Laid-Open No. 4-257908. The invention disclosed in the above publication is provided with means for turning on / off power supply to a memory unit in which a memory and a backup power supply are mounted in the same package, and after writing specific data to a specific address. The backup function is checked by turning off the power supply for a certain period of time and then turning it on again to read the data at the specific address and confirm the data.

[0006]

A backup power source is generally provided in case of an emergency such as power failure or erroneous operation, but it is often not started for a long time. It is a problem that the backup function is not checked because the backup function does not work and important stored contents may be erased.

As one of means for solving this problem, there is a backup function test method disclosed in the above-mentioned Japanese Patent Laid-Open No. 4-257908. In this method, the power supply is cut off for a certain period of time in order to perform the function test. However, there is a problem that the use of the memory must be interrupted during that time.

In a system that operates continuously for a long time,
It is virtually impossible to suspend the use of memory for the backup function check. On the other hand, there is a contradiction that it is necessary to check the backup function because the backup power supply start-up interval becomes extremely long and the probability of failure increases as the system operates continuously for a long time. SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery backup memory unit and a backup function test method that overcome the above drawbacks and can confirm the backup function without interrupting the use of the memory.

[0009]

A battery backup memory unit of the present invention is a battery backup memory unit having a memory having a backup power source and an interface control means for connecting a memory access from the outside to the memory. Power supply control means for individually controlling the supply of main power supplied to each of the memories having two systems and each having a backup power supply, and memory check means for checking the backup function of the memories. Arbitration means for arbitrating read / write operations performed in response to external access to the two systems of memory and read / write operations required for the check function and the copy function by the memory check means. However, the memory check means is preset. Starting the backup function test operation of the memory according to the conditions, of the two systems memory,
The main power supply of the memory of one system to be tested is shut off for a predetermined time via the power supply control means, the read data of the memory to be tested is read after the power supply is restored, and the backup function is checked. Read the read data from the non-test target memory that has been continuously responding to the memory access, copy the memory to the test target memory, and then perform the same operation for the other 1 system memory to perform 2 system It has a function to check the backup function of the memory.

In the backup function test method of the present invention, the number of memory units backed up by the battery is 2
A backup function test method performed by a system-provided memory unit, which shuts off the main power supply of one system memory to be tested among two systems of memory for a predetermined time,
After the power is restored, the read data of the test target memory is read into the memory check unit to check the backup function, and after the check is completed, the read data of the non-test target memory that has continuously responded to external memory access during the test period is read. The data is read and copied to the memory to be tested, and then the same operation is performed for the other one-system memory to check the backup function of the two-system memory.

[0011]

If there is an abnormality in the backup function of the battery backup memory unit, the data in the memory will be lost when the main power supply is cut off for the test, so the abnormality is detected by the memory check operation.

During the above-mentioned memory check, even if the main power supply of the memory of one system is cut off, the power can be continuously supplied to the memory of the other system. External access becomes possible, and read / write operations can be performed using a memory of another system that is not the test target. The write data at this time is copied from the non-test target system to the test target system by the memory copy operation. External access is possible even during the memory check period after the main power is restored, the read operation uses the non-test target system, and the write operation is performed for both systems. At this time, arbitration is performed so that external access does not conflict with the memory check operation.

With the above operation, the backup function can be tested without interrupting the use of the memory.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a flow chart of the embodiment of the present invention.

The battery backup memory unit of the present invention comprises an interface control circuit 11 and a memory control circuit 12.
Of the # 0 system memory circuit 15 and the # 1 system memory circuit 16 and the backup power supplies 18 and 19 for backing up the memory circuits 15 and 16 respectively. The memory access arbitration circuit 14 is connected to an external circuit, and receives an external access command.
Interface control circuit 11 that receives the necessary signals by connecting to the # 0 system memory circuit 15 or the # 1 system memory circuit 16 via the memory bus 17, and autonomously in accordance with preset conditions. Then, the memory check operation is started, and the power supply control circuit 13 is instructed to shut off the external power supply of the memory circuits 15 and 16 of the # 0 system or # 1 system to be subjected to the memory check for a preset time, and then the target after the recovery. Memory read data is transferred to the memory bus 17
Of the memory control circuit 12 for copying the read data of the non-target memory to the target memory after checking, and for checking the contents and checking the contents if there is a failure, and the memory circuits 15 and 16 from the outside. A power supply control circuit 13 for individually controlling the supply of main power supplied to each in accordance with a command from the memory control circuit 12, and an interface control circuit 1.
Memory access arbitration circuit 14 for arbitrating and arbitrating execution of read / write operations to two systems of memory circuits 15 and 16 according to commands of 1 and memory control circuit 12, and interface control circuit 11 and memory control circuit 12 as two series of memories. The memory bus 17 is connected to the circuits 15 and 16.

Next, the operation of the battery backup memory unit of the present invention for external access will be described. The memory access from the outside is accepted by the interface control circuit 11. The interface control circuit 11 sends a memory access request to the memory access arbitration circuit 14. The memory access arbitration circuit is the memory control circuit 12
After arbitrating with the memory access request from, the memory access permission is returned.

In response to this, the interface control circuit 11 accesses the # 0 system memory circuit 15 and the # 1 system memory circuit 16 via the memory bus 17. At this time, the memory circuits of both systems operate during the write operation, but the memory circuits of the act system operate during the read operation. This act / standby designation is performed from the memory control circuit 12 via the memory bus 17.

Next, the test operation of the backup function test method of the present invention will be described with reference to FIG. The backup function test operation of the memory control circuit 12 is autonomously activated in accordance with a preset condition (S1), and the memory circuit to be tested is put into the in-testing state (standby and write protected) via the memory bus 17. The non-test target memory circuit is set to act (S2).

Next, the power supply control circuit 13 is instructed to shut off the external power supply of the memory circuits 15 and 16 of the # 0 system or # 1 system to be subjected to the memory check, and supply the power after a preset time elapses. It is restored (S3).

After recovery, the memory circuit to be tested is set to the operating state (standby and write enabled), and the memory circuit to be non-tested continues to act (S4).

After that, read data check of all addresses of the memory circuit of the system to be tested is performed. Memory control circuit 1
2 requests the memory access arbitration circuit 14 for memory access. The memory access arbitration circuit 14 arbitrates the memory access request from the interface control circuit 11, and then returns the memory access permission.

In response to this, the memory control circuit 12 makes a read access to the memory circuit to be tested via the memory bus 17. The read data is received and checked by the memory control circuit 12. There are various check methods, but the validity check is generally used. This read access is repeated for each address to check the data of all addresses (S5).

If a failure is found in the backup function as a result of the memory data check in S5 (S6), an alarm is displayed on the memory unit or an alarm is output to an external circuit, and the test is interrupted (S7).

Next, the data copy operation is performed. The memory control circuit 12 sends a memory access request to the memory access arbitration circuit 14. Memory access arbitration circuit 14
Arbitrates for a memory access request from the interface control circuit 11, and then returns a memory access permission.

In response to this, the memory control circuit 12 performs read access to the non-test target memory circuit via the memory bus 17, and at the same time performs write access to the test target memory circuit to perform memory copy. This operation is repeated for each address to perform memory copy of all addresses (S8).

After the test of one system is completed, the system is switched (S9) and the test of the other system is performed (S1).
0) The test of both lines is completed (S11).

Due to the function of the memory access arbitration circuit 14, the memory access from the outside is accepted even during the power-off operation of the backup function test, the read data check operation and the data copy operation, so that the use of the memory circuit is interrupted. Never. In addition, the latest data is always written to the non-test target memory circuit, and the latest data is written to the test target memory circuit except in the initial period of the backup function test operation. , The memory contents of both systems can be completely matched.

When the test is interrupted due to a failure, the system is not switched, so that the system can continue to be used in another system and the data is not lost.

[0029]

As described above, according to the battery backup memory unit and the backup function test method of the present invention, the operation of the backup function can be tested without interrupting the use of the memory.

As a result, it is possible to prevent accidents such as loss of stored data at the time of power failure.

Also, for example, when the memory unit is removed and the data is handed over by connecting to the totalizing device, the data for one day collected by the battery backup memory unit mounted in the cash register is deleted. You can deliver the memory unit without worry.

Furthermore, since the system has two series of memory circuits and a backup power source, even if a failure occurs in one system, the other system is normal and there is no fear of losing stored data.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of an embodiment of the present invention.

FIG. 3 is a block diagram of a conventional example.

[Explanation of symbols]

 11 interface control circuit 12 memory control circuit 13 power supply control circuit 14 memory access arbitration circuit 15 # 0 system memory circuit 16 # 1 system memory circuit 17 internal memory bus 18 # 0 system backup power supply 19 # 1 system backup power supply 31 interface control circuit 32 memory circuit 33 backup power supply S1 to S11 step of processing procedure

Claims (2)

[Claims] 1. A battery backup memory unit having a memory having a backup power supply and an interface control means for connecting a memory access from the outside to the memory, wherein the memory has two systems, each having a backup power supply, Power control means for individually controlling the supply of main power supplied to each of the two systems of memory, a memory check means for checking the backup function of the memory, and an external device for the two systems of memory. The read / write operation performed according to the access, and the read / write operation required for the check function and the copy function by the memory check means, and an arbitration means for arbitrating the memory check means. Back up the memory according to the preset conditions. Start function test operation,
Of the two systems of memory, the main power supply of the one system memory to be tested is shut off for a predetermined time via the power supply control means, and after the power is restored, the read data of the memory to be tested is read to check the backup function. Then, after checking, read the read data of the non-test target memory that has continuously responded to external memory access during the test period, copy it to the test target memory, and then to another one system memory. Repeat the same procedure for the above 2
A battery backup memory unit having a function of checking a backup function of a system memory. 2. A backup function test method performed by a memory unit provided with two systems of memory units backed up by a battery, wherein the main power source of one system memory to be tested among the two systems memory is After shutting down for a predetermined time, after reading the power supply, the read data of the memory under test is read into the memory check means to check the backup function, and after the check is completed, the memory access from outside is continuously supported during the test period. Read the read data from the non-test target memory, copy it to the test target memory, and then perform the same operation for the other 1-system memory to check the backup function of the memory of both systems. Characteristic backup function test method.