JPS60140439A - Self-diagnostic method of printed circuit board - Google Patents

Abstract

PURPOSE:To execute the self-diagnosis of a printed board in a short time by storing a diagnostic program in a ROM of a microcomputer in advance or replacing it with a ROM storing a diagnostic program to execute the diagnostic program. CONSTITUTION:In one set of microcomputers coupled together, one is used as a master microcomputer and the other is a subordinate microcomputer, the subordinate computer is controlled by the master computer with the diagnostic program stored in advance in the ROM to diagnose the normality of the data bus between both the microcomputers and the computers themselves. When a test command from the outside of the printed circuit board 6 is inputted to the microcomputer 1, a call signal is given to the microcomputer 2. The data bus is switched into the output mode, call response data is set to the bus and the input of the call response data is requested to the microcomputer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a self-diagnosis method for a printed circuit board, and more particularly to a self-diagnosis method for a printed circuit board equipped with a plurality of organically coupled microcomputers.

[Prior art]

The basic configuration of a microcomputer is centered around the CPU.
Contains OM, RAM, input/output boards, and data buses and control paths connecting them.

Multiple microcomputers are mounted on one printed circuit board, and they are organically combined by allowing duplication, such as one microcomputer being combined with multiple microcomputers, for one or more purposes. In a printed circuit board that has the intelligence to function, input signals undergo complex logical operations, time delay operations, and the like.

Therefore, if an abnormality occurs such as a failure in the data bus and control bus between the microcomputers of each set of interconnected microcomputers, or poor contact between the microcomputers, it is difficult to find the location of the failure.

Diagnostic devices for finding these faults are known, but they require specialized devices depending on the microcomputer being used, and the microcomputer program used for diagnosis. The problem is that it takes a lot of time to find the location of a failure because it requires a lot of follow-up.

[Purpose of the invention]

An object of the present invention is to store in advance a diagnostic program for a partner microcomputer to be mutually coupled in the ROM of a microcomputer, or
It is an object of the present invention to provide a self-diagnosis method for a printed circuit board that does not require a dedicated diagnostic device and can find a failure point in a short time by replacing the OM and executing the diagnostic program.

[Structure of the invention]

A self-diagnosis method for a printed circuit board according to the present invention mounts a plurality of microcomputers that are organically combined with each other on a single printed circuit board with overlap allowed, and
One of the microcomputers in each group starts up, calls the other, transfers diagnostic data, and determines whether or not there is a predetermined response to the diagnostic data.
The apparatus is configured to determine a bus between a set of said microcomputers and the health of each said microcomputer.

[Explanation of Examples]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of failure diagnosis in the embodiment shown in FIG.

As shown in FIG. 1, the microcomputer l.

. . . , 5 are mounted on one printed circuit board 6.

Microcomputer 1 is microcomputer 2, ~
, 5 and bus 12. ~, 15, Microcombi-
5 is a microcomputer 1.3°4 and a bus 15.5
3.54, each of which is configured to serve one or more purposes. However, bus 12
．． ~s 15 v 53 t 54 each include a data bus and a control bus.

〒ICROCOMBITA 1, 3. . . . , 5 are connected to the column circuit through external terminals 11 w 13 s 14 + 15, respectively.

In the present invention, each set of microcomputers are connected to each other, with one being a main microcomputer and the other being a subordinate microcomputer.
Control is performed according to a diagnostic program stored in advance in the OM to diagnose the health of the data bus and control bus between both microconbeaters and both microconbeaters.

As an example, a diagnostic operation between the microcomputer 1 and the microcomputer 2 as shown in FIG. 2 will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart for explaining the operation of the microcomputer 1, and FIG. 4 is a flowchart for explaining the operation of the microcomputer 2. In FIG.

Since the microcomputer 2 has no input/output terminals outside the printed circuit board 6, the microcomputer 1 is set on the main side.

When a test instruction is input to the microcomputer 1 from the external circuit of the printed circuit board 6, the microcomputer 1 sends a calling signal to the microcomputer 2 (71).

When microcomputer 2 recognizes the calling signal (
ss), switches the data bus to the output mode (86), sets the paging response data on the data bus (87), and requests the microcon beater 1 to input the paging response data (88).

When the microcomputer l receives a call response data input request (72), it inputs the call response data, analyzes the data, and when the analysis result determines that the call has been accepted, it outputs a call signal (73). Then, the call is canceled (74).

Subsequently, a response signal for canceling the call is sent to the microcomputer 2 (75).

When microcomputer 2 receives a response to cancel the call (89), it switches the data bus to input mode (90).
%Call response data input request is canceled (91).

When microcomputer 1 recognizes that the input request for call response data has been released (76), it switches the data bus to output mode (77) and sets diagnostic data on the data bus (78). L (79) requests input of diagnostic data.

When the microcontroller 2 recognizes that it has received a request to input diagnostic data, it accepts (92)% of the diagnostic data, analyzes it, and sends the analysis result back to the microcomputer 1 (93).

When the microcontroller recognizes the response of the analysis result (80)%, it releases the diagnostic data input request (81).
.

When the microcomputer 2 recognizes the release of the diagnostic data input request (94), it sends a response to the microcomputer 1 indicating the recognition (95), releases the recognition response signal (96), and ends the diagnosis.

When the microcomputer 1 recognizes the response from the microcomputer 2 indicating that the diagnostic data input request has been canceled (82), it switches the data bus to the input mode (82).
83) Finish % diagnosis.

In addition, all judgment operations are carried out after a predetermined period of time has elapsed, which is set for each case.If "NO" occurs, the subsequent operations are interrupted, and the microcomputer 1 detects a fault from the output terminal to the external display circuit. Send a signal.

In addition, if the printed circuit board 6 does not have an external input terminal for inputting test instructions, by replacing the ROM with a ROM that stores a diagnostic program in advance, the program will automatically proceed and the results will be sent to the bus of the main microcomputer. You can omit starting the test instructions by outputting them. In that case, the test results can be determined by using a general-purpose measuring device such as a synchroscope to check the microcomputer bus designated in advance for outputting the test results.

〔Effect of the invention〕

As described above, the self-diagnosis method for a printed circuit board according to the present invention involves storing in advance a diagnostic program for a partner microcomputer to be mutually coupled in the ROM of a microcomputer, or a ROM storing a diagnostic program.
By replacing this with the diagnostic program and running the diagnostic program, the failure location can be found in a short time without the need for a dedicated diagnostic device, which has the effect of improving adjustment and maintenance efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing an example of failure diagnosis in the embodiment shown in FIG. 1, and FIG. 3 shows the operation of the main microcomputer in FIG. FIG. 4 is a flowchart for explaining the operation of the microcomputer shown in FIG. 2. In the figure, 1. ~, 5... Microcomputer, 6... Printed circuit board, 12. ~,15
,53゜54... bus. Yasushi I Betsu 2nd 3rd Concave 4th

Claims (1)

[Claims] A plurality of microcomputers organically coupled with each other are mounted on a single printed circuit board, and one of the microcomputers in each set of mutually coupled microcomputers starts up and activates the other. The printer is characterized in that the bus between the set of microcomputers and the health of each of the microcomputers is determined based on whether or not there is a predetermined response to the diagnostic data. How to self-diagnose a circuit board.