JPH04123440U - micro computer - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent malfunctions in microcomputers caused by incorrect settings of program counter values. [Structure] In the program counter value monitoring block 3, the counter value of the program counter 2 and the program area input from the program area range information storage circuit 4 are compared and verified, and the counter value of the program counter 2 is A search is made to see if it is within the program area. If the counter value is outside the program area range, the program counter setting circuit 5 outputs arbitrary address information corresponding to the value within the program area range to the program counter 2. ,
Set to program counter 2. As a result, the microcomputer 1 performs normal operation based on the value of the program corresponding to the arbitrary address information, and abnormal operation of the microcomputer is prevented.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to microcomputers, particularly microcomputers. , a device that monitors abnormalities in program counter values due to program errors, etc. The present invention relates to a microcomputer having the following functions.

0002

[Conventional technology]

In a conventional microcomputer, the microcomputer Check whether the program counter value is outside the range of the program area. The current situation is that these systems do not have any kind of monitoring function.

0003

[Problem that the idea aims to solve]

In the conventional microcomputer mentioned above, the program counter value is No monitoring function is provided to check whether the value is outside the program area. Therefore, an abnormality in the program counter value may occur due to a program error (program error). When setting a value outside the RAM area range), the microcomputer operates normally after that. The disadvantage is that it cannot work.

0004

[Means to solve the problem]

The microcomputer of this invention stores program area range information in advance. A program area range information storage circuit and a program area storage circuit that stores program address information. program counter and program address information in the program counter. A program counter value setting circuit for setting the program counter, and a program counter value setting circuit for setting the program counter. and the program area range information storage circuit input from the program area range information storage circuit. The counter value is outside the program area range by comparing with the RAM area range information. When the value is reached, the program counter value is transferred to the program area. Program counter value monitoring block that forcibly changes the counter value to a predetermined value within the range. It consists of a

[0005]

【Example】

Next, the present invention will be explained with reference to the drawings.

[0006] FIG. 1 is a block diagram showing one embodiment of the present invention. As shown in Figure 1, the book The microcomputer 1 of the embodiment includes a program counter 2 and a program counter 2. Counter value monitoring block 3, program area range information storage circuit 4, and program and a time counter setting circuit 5. Note that in Figure 1, the original Other components included in the microcomputer 1 are not specifically covered by this invention. Since it is not related, it is completely omitted and not listed. Also shown in Figure 2 is a flowchart showing the operation of the present invention.

[0007] In FIG. 1, program counter 2 is the program counter of microcomputer 1. This is a counter that holds address information for program memory. A predetermined program memory address is set by the data setting circuit 5 via the internal bus 101. Dress information is set. On the other hand, the program area range information storage circuit 4 contains Information defining the range of the program area in the computer 1 is stored. In the program counter value monitoring block 3, the program counter The counter value input from the counter 2 via the internal bus 101 and the program area range The program area input from the surrounding information storage circuit 4 via the internal bus 101 is The counter value input from program counter 2 after comparison is verified. The counter value is searched to see if it is within the program area, and if the counter value is outside the program area. If the value is , it instructs program counter 2 to correct the address information. A control signal shown is output and input to the program counter setting circuit 5. In the program counter setting circuit 5, in response to the control signal, the program counter setting circuit 5 receives the control signal. To deal with incorrect settings of values outside the program area range, the program counter 2 Arbitrary address information (in the program area) for program memory is output. , is sent to the program counter 2 via the internal bus 101, and the arbitrary address is sent to the program counter 2 via the internal bus 101. response information is set. As a result, the microcomputer 1 Normal operation starts from the program value corresponding to the address information.

[0008] As mentioned above, FIG. 2 is a flowchart showing the operation of the present invention. Through the judgment process in step 21, the program counter value is determined to be within the program area range. If the value is outside the range, the program counter is Arbitrary address information is set in the counter 2 by the program counter setting circuit 5. be done.

[0009]

[Effect of the idea]

As explained above, the present invention is a program counter in a microcomputer. In an abnormal situation where the value of the parameter is outside the program area, the above By changing the value of the program counter, you can Avoid abnormal situations in the above program values that occur, and This makes it possible to continue executing the program from the microcomputer. This has the effect of preventing abnormal operation of the device.

[Brief explanation of drawings]

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

FIG. 2 is a diagram showing a flowchart of operations in this embodiment.

[Explanation of symbols]

1 Microcomputer 2 Program counter 3 Program counter value monitoring block 4 Program area range information storage circuit 5 Program counter setting circuit

Claims (1)

[Scope of utility model registration request] 1. A program area range information storage circuit that stores program area range information in advance, a program counter that stores program address information, and a program counter that sets program address information in the program counter. A value setting circuit compares and verifies the counter value in the program counter with the program area range information inputted from the program area range information storage circuit, and when the counter value becomes a value outside the program area range. A microcomputer comprising: a program counter value monitoring block that forcibly changes the program counter value to a predetermined counter value within the program area range.