JPH03136153A - Microcontroller - Google Patents

Abstract

PURPOSE:To restore a system to the normal operation without the malfunction even at the time of the occurrence of data abnormality during power down by providing means for generation and storage of redundant data and providing a data checking means and a protecting means. CONSTITUTION:When the system is restored from power down, redundant data is read out from a redundant data storage means 7, and a comparing and checking means 8 compares data stored in a data storage means 5 and redundant data with each other to discriminate whether error occurs in this data or not. That is, when redundant data is generated, each data stored in the data storage means 5 is obtained and is compared with redundant data, and data is judged to be normal in the case of coincidence but the occurrence of error is judged in the case of disaccord. If the occurrence of abnormality (error) is judged, the system is reset to repeat the operation from initialization. Thus, the malfunction of the system is prevented to restore the system to the normal operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microcontroller designed to prevent malfunctions.

[Conventional technology]

FIG. 3 is a functional block diagram showing an example of a conventional microcontroller (MCU). In the figure, 1 is a clock generation circuit that supplies a system clock, 2 is a control means that controls the system in synchronization with the system clock, and 3 is a clock generation circuit that supplies a system clock.
is a system stop means that temporarily reduces power consumption by stopping the system clock. Further, 4 is a data processing means for calculating and processing data, and 5 is a data storage means for storing data.

Next, the operation will be explained. FIG. 4 is a flowchart showing the operation of the microcontroller shown in FIG.

When the system is started (step 10), the data processing means 4 initializes data (step 1), and then the control means 2 and the data processing means 4 sequentially execute programs.

During a series of processes, when there is no more process to be executed, the control means 2 causes the system stop means 3 to stop the system clock in order to reduce power consumption (step 13), and enters the power down mode. At this time, the data obtained within the system is stored in the data storage means 5. Then, when it becomes necessary to restart the program due to some external factor and the clock generation circuit 1 is activated accordingly and starts supplying the system clock, the control means 2 and The data processing means 4 sequentially executes the program (step 1
7). At this time, data stored in the data storage means 5 is used. Furthermore, when all the programs are completed, the operation ends (step 18).

[Problem to be solved by the invention]

Conventional microcontrollers are configured as described above, so if there is a data abnormality (error) in the data storage means 5 due to external noise etc. during power down, the erroneous error will be detected after returning from power down. There was a problem that the system would malfunction because the data would be used to continue processing.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a microcontroller that can prevent system malfunctions when restarting operation after power down.

[Means to solve the problem]

In the present invention, a microcontroller is provided with a system stop means for temporarily stopping the system during a period when data processing by the own system is unnecessary, thereby temporarily reducing the power consumption of the system: redundant data creating means for creating redundant data for data to be stored in data storage means in the microcontroller when the system is temporarily stopped by the system stopping means; redundant data for storing the redundant data; storage means; by using the redundant data read from the redundant data storage means when the temporary suspension of the system is released;
data investigating means for investigating whether an error has occurred in the data in the data storage means during the period of temporary suspension; when the error has occurred in the data;
A system protection means is provided for protecting the system from malfunction by restoring the system to a normal data state.

[Effect]

The redundant data creation means of the present invention provides redundancy to data before the system enters a temporary stop state, that is, a power down mode. Then, after returning from the power down mode, the data investigation means uses the redundant data to investigate whether there is any data abnormality (error). If there is an abnormality, the system protection means allows the system to return to normal operation without malfunction.

〔Example〕

FIG. 1 is a functional block diagram of a microcontroller showing one embodiment of the present invention. In the figure, 1 to 5 are the third
This is substantially the same as the conventional one shown in the figure. 6 to 9 are means newly provided according to the characteristics of the present invention, and among these, 6 is a redundant data creation means for creating a redundant part (redundant data) in order to provide redundancy to the original data; 7 is redundant data storage means for storing this redundant data. Further, 8 is a data comparison investigation means for comparing original data and redundant data, and 9 is a system protection means for restoring the system to normal operation.

Next, the operation will be explained. FIG. 2 is a flowchart of this embodiment. After the start of step 10, initial settings similar to those of the conventional example are performed in step 11, and then data processing is performed.

When data processing in this system is no longer required, redundant data for checking is created for each data to be stored in the data storage means 5 by the redundant data creation means 6 (step 12).

Although various types of redundant data can be used, for example, redundant data based on the checksum method is used. That is, the lower 8 bits of the sum of each data to be stored in the data storage means 5 are made redundant data.

The redundant data created in this way is stored in the redundant data storage means 7. Then, power down processing similar to the conventional example is performed (step 13).

When the system returns from the power down mode in step 14, redundant data is read from the redundant data storage means 7. Then, the comparison investigation means 8 determines whether an error has occurred in the data stored in the data storage means 5 by comparing this data with the redundant data (step 15). That is, when the redundant data is created according to the checksum method, the lower 8 bits of the sum of each data stored in the data storage means 5 are obtained and compared with the redundant data. If they match, the data is normal; if they do not match, it is determined that an error has occurred.

If the data is normal, proceed to steps 16 to 17 and continue processing according to the program, but if it is determined that an abnormality (error) has occurred, step 1
Return to step 1 to reset the system and repeat the operation from the initial settings. This is done by the system protection means 9 of FIG. 1, thereby preventing malfunctions of the system.

In the above embodiment, the checksum method is used in response to a software configuration, but in the case of a hardware configuration, a parity bit or the like may be created as redundant data. In addition, when the redundant data is data that only allows error detection, the initial settings return the system to a normal data state, but when creating data that also allows error correction as redundant data, it can be used to perform error correction. If you do this, there is no need to return to the initial settings. In any case, system malfunctions can be prevented.

〔Effect of the invention〕

As described above, according to the present invention, the microcontroller is provided with a means for creating and storing redundant data, as well as a data investigation means and a protection means. Even if an abnormality occurs, the system does not malfunction and can return to normal operation.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of a microcontroller according to an embodiment of the present invention, FIG. 2 is a flowchart showing an example of the operation of this embodiment, FIG. 3 is a functional block diagram showing an example of a conventional microcontroller, and FIG. The figure is a flowchart showing an example of the operation of a conventional microcontroller. In the figure, 2 is a control means, 3 is a system stop means, and 4 is a control means.
5 is a data processing means, 5 is a data storage means 6 is a redundant data creation means, 7 is a redundant data storage means, 8 is a data comparison and investigation means, and 9 is a system protection means. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) In a microcontroller, the microcontroller is equipped with a system stop means that temporarily stops the system during a period when data processing by the own system is unnecessary, thereby temporarily reducing the power consumption of the system. redundant data creation means for creating redundant data for data to be stored in data storage means in the microcontroller when the system is temporarily stopped by the system stop means; and redundant data storage for storing the redundant data. means, when the temporary suspension of the system is released, the redundant data read from the redundant data storage means is used to update the data in the data storage means during the period of the temporary suspension. a data investigation means for investigating whether an error has occurred; and a system protection means for protecting the system from malfunction by restoring the system to a normal data state when the error has occurred in the data. A microcontroller characterized by: