JPS6089993A - Method of detecting malfunction of printed board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Background and Objectives of the Invention] The present invention relates to a method for detecting an abnormality in a printed circuit board, and particularly to a method for detecting an abnormality in a printed circuit board, and in particular, detects an abnormality in a system using a microcomputer through a common bus among a group of logic boards in the system. This relates to an abnormality detection method for a printed circuit board connected to a device (hereinafter abbreviated as CPU).
Among the boards connected to U via a common bus, the data output circuit board is provided with an interface circuit in order to take in data from the common bus. When the CPU performs abnormality detection on a board-by-board basis, it writes data to the interface circuit of the target data output circuit board,
The data is read back and the data on both sides is verified to match.

However, this method has the disadvantage that it cannot detect an abnormality in the following cases. For example, if the connection between the target data output circuit board and the common bus is incomplete or disconnected, the CPU will not be able to access the data because the target board is abnormal. , since the data to be read will be undefined, it should be possible to detect a board abnormality by matching the data on both sides, but the data written by the CPU is normally charged on the common bus for a certain period of time due to the stray capacitance of the bus. If the CPU attempts to read data before the common bus is completely discharged, the data held in the common bus will be directly read, resulting in the inconvenience that an abnormality in the target board cannot be detected by matching.

FIG. 1 is a block diagram of a system using a microcomputer, in which a plurality of printed circuit board units 102 are connected to a common bus 101 of a CPU Uloo of the microcomputer.

In this type of configuration, the number of units 102 increases as the amount of data increases, and the number of units that perform data input/output processing largely depends on the amount of data. If an abnormality occurs in one of these many units, the CPU 100 immediately detects the abnormality, but according to the conventional method, the data input/output circuit unit for performing data input/output processing is In some cases, even if a failure such as a poor connection (contact) or no connection occurs, it may not be detected, and it takes a long time to recover from the abnormality.

The present invention has been made in view of the above, and its purpose is to provide a printed circuit board abnormality detection method that can reliably detect a printed circuit board abnormality in any abnormal state. .

[Summary of the invention]

A feature of the present invention is that when diagnosing a failure of a printed circuit board of a logic board group connected to a central processing unit of a system using a microcomputer via a common bus, The data written to the board via the data bus is compared and verified with the data written to the printed circuit board in 1. is inverted and read into the central processing unit via the data bus. According to the present invention, an abnormality in the printed circuit board is detected.

〔Example〕

An embodiment of the method of the present invention will be described in detail below with reference to FIG.

In the present invention, since the data written by the CPU of a system using a microcomputer to the data input/output circuit unit is always inverted from this data input/output circuit unit, abnormality detection is performed by performing these data comparison processes. That's what I do.

FIG. 2 is a block diagram of a data input/output circuit unit for explaining an embodiment of the printed circuit board abnormality detection method of the present invention. In FIG. 2, 200 is an address bus, 201 is a data bus, 202 is a decoder, 203 is a bidirectional driver/receiver circuit, and 204 is a data holding circuit. First, the CPU 100 in FIG. 1 is connected to the target external device. The address data of the data input/output circuit unit currently in use is sent to the address bus 200. The selected data input/output circuit unit takes in the address data, encodes it in the decoder 202, and uses it as a control signal inside the circuit. Next, the CPU 100 writes test data to the data input/output circuit unit via the data bus 201.

Here, a bidirectional driver/receiver circuit 203 is provided as an interface circuit between the data input/output circuit unit and the CPU 100, and the test data taken in by this circuit is driven and sent to the data holding circuit 204. The data holding circuit 204 inverts the received data and returns it to the bidirectional driver/receiver circuit 203 via the data bus 201 to the CPU 1.
Send to 00. Then, the CPU 100 compares the written test data with the inverted data and performs abnormality detection processing for the unit.

As described above, according to the embodiment of the present invention, the data input/output circuit unit internally reflects the data sent from the CPU 100 and returns it to the CPU 100.
100 compares the written data with the inverted data,
Since abnormality detection processing is performed for the unit, the abnormality can be reliably detected even in such an abnormal state, and the abnormality function can be improved. Moreover, early detection is possible.

Note that although the case of a data input/output circuit unit has been described above, it can also be applied to any printed circuit board connected to the CPU 100 via a common bus, and the same effect can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reliably detect an abnormality in a printed circuit board even in the above conditions, and there is an effect that an abnormality detection function can be improved and early detection can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a system using a microcomputer, and FIG. 2 is a block diagram of a data output circuit unit for explaining an embodiment of the printed circuit board abnormality detection method of the present invention. 100: CPU, 101: Common bus. 102: Unit, 200 Andres bus. 201: Data path, 202-digit decoder, 203: Bidirectional driver/receiver circuit. 204: Data holding circuit. 7- 1st mouthful 2nd drink

Claims (1)

[Claims] (1) When diagnosing the failure of a printed circuit board in a group of logical boards connected to the central processing unit of a system using a microcomputer via a common bus, the central processing unit The data written via the data bus and the data written to the printed circuit board are inverted and compared with the data read into the central processing unit via the data bus to detect an abnormality in the printed circuit board. A method for detecting an abnormality in a printed circuit board, characterized in that: