JPH0820490B2 - Automatic test control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A test method of a printed board having both bidirectional and unidirectional interfaces and having an interface conversion function by a program control method. Prepare a printed circuit board with the transmission / reception relationship of the directional interface replaced, place a test program on it, and connect it so that it faces the printed circuit board under test for diagnosis and testing. This makes it possible to provide a small and inexpensive test apparatus by utilizing the interface function and program control function of the printed board.

[Field of Industrial Application] The present invention relates to a test method for a printed board having a micro program control function.

At present, a printed board having a function of converting a data transfer method between two interfaces is realized by the micro program control method, and is widely used for connecting an input / output device in a small computer or the like.

The present invention relates to a test system for automatically testing such a printed board.

[Prior Art] Conventionally, in order to test a printed board as described above,
It was common to use either of the following two methods.

FIG. 3 and FIG. 4 are diagrams for explaining the prior art.
Printed board under test (UUT) as shown in Fig. 3 (a)
Has a bidirectional interface A and a unidirectional interface B, and has a function of performing interface conversion of data transfer between both interfaces under program control.

(1) Test the printed circuit board (UUT) under actual operation. That is, the CPU (central processing unit) is connected to the bidirectional interface A, and the DEV (input / output device) is connected to the unidirectional interface B. As shown in FIG.
Alternatively, as shown in FIG. 3 (b), the test is carried out as an “imazuru” formula.

(2) Test using a dedicated printed board tester or a general-purpose printed board tester. That is, as shown in FIG. 4 (a), an input pattern is generated to generate a printed board under test (UU).
By inputting to T), recording the output pattern and comparing this with the expected value, by the so-called function tester,
Alternatively, as shown in FIG. 4 (b), a probe inputs a signal from the lead of each functional component onto the printed board,
Test using a so-called in-circuit tester, which measures the output from the lead.

[Problems to be Solved by the Invention] The conventional test methods (1) and (2) have the following problems.

In the method (1), in the method shown in FIG. 3 (a), it is necessary to install a plurality of product CPUs, and a large floor area is required, which increases the test cost.
Further, in the method shown in FIG. 3 (b), the cable connection becomes complicated, and there is a risk of causing an erroneous operation or an erroneous test due to human error. Further, the output from the interface B requires a pass / fail judgment by a person through a print result or a display result, and it is impossible to perform the pass / fail judgment completely.

The method (2) requires expensive tester equipment,
In addition, in this test, it is possible to detect manufacturing defects and fixed failures of parts, but it is not possible to detect timings, malfunctions, etc. due to actual operating conditions.After this test step, connect to the CPU to confirm normality. Is being done.

The present invention is intended to provide a new automatic test system that solves such problems.

[Means for Solving Problems] FIG. 1 shows a principle block diagram of the automatic test system of the present invention.

In FIG. 1, reference numeral 1 denotes a printed board to be tested, which has a bidirectional interface A section and a unidirectional interface B section, and stores a ROM for storing an interface conversion program and data and a microprogram control for executing microprogram control. It is provided with a circuit (or a microprocessor and peripheral circuits) and has a function of performing conversion between both interfaces under microprogram control (or microprocessor control).

The reference numeral 2 denotes a test printed board, and in terms of hardware, transmission and reception of the unidirectional interface B section of the printed board 1 under test are simply replaced in reverse.
A test program is placed on the built-in ROM instead of the interface conversion program in the printed board 1 under test. The test program is a program for generating a test signal and comparing a response signal to the test signal with an expected value to check whether they match.

The printed board 1 under test and the printed board 2 for test are opposed to each other in a one-to-one manner and are connected by a bidirectional interface A and a unidirectional interface B, respectively.

[Operation] The test printed board 2 has a function as a tester for the printed board 1 under test by loading the test program in its built-in ROM.

That is, a command is input to the printed board 1 to be tested through the interface A, a response signal thereof is taken in through the interface B, and is compared with an expected value for inspection. The expected value is when the test signal is input to a normal printed circuit board.
It is a signal value of a normal response signal to be output.

As described above, the conventional method is "dripping" of the printer or the display, and the normality is checked by visually checking the data of the paper output by the printer or the display data.
Since the expected value of the interface output is checked via the actual interface at the actual speed, it is possible to perform a deep diagnostic test.

In addition, the hardware function of the printed circuit board to be tested can be used almost as it is, and it can be used as a tester. Compared with the conventional method, no human intervention (cable connection, CPU operation, visual inspection) is required, so unattended test is possible. It will be possible.

[Example] The gist of the present invention will be specifically described with reference to an example shown in FIG.

In FIG. 2, reference numeral 1 is a ratio test printed board, which is a bidirectional interface A section 11 and a unidirectional interface B12.
And an interface conversion unit 13 that performs interface conversion by a microprogram.

Interface conversion is performed by the central processing unit 3 shown by a broken line.
Of the I / O device 4 and the unidirectional interface of the input / output device 4, which is also indicated by the broken line, and involves format conversion, code conversion, and timing conversion.

The interface conversion unit 13 has a ROM that stores an interface conversion program and conversion data, and an SRAM that is loaded with necessary programs and data and that performs microprogram control together with peripheral circuits (not shown).

2 is a test printed board, and in terms of hardware,
The difference from the printed circuit board 1 to be tested is that the unidirectional interface B section 12 is replaced with a unidirectional interface B section 22 to replace the transmission / reception relationship, and the other configurations are the same.

In the ROM of the test circuit section 23, a test program and data are mounted instead of the program and data of the printed board 1 under test, and the required program and data are loaded into the SRAM to provide a function as a tester. It will be.

In this embodiment, the same part as the program of the printed board 1 to be tested is used to generate the expected value at the time of the test.

The test printed board 1 and the test printed board 2 are connected to each other through both interfaces.

The test printed board 2 uses the interfaces A and B, and the CPU (central processing unit) shown by the broken line in FIG.
The simulation function 3 and the DEV (input / output device) 4 simulation function are realized.

[Effects of the Invention] As described above, according to the present invention, the hardware function of the printed circuit board under test can be used as it is, it is small and inexpensive, and it is easy to deal with the interface change etc. by the program modification. It is possible to provide an automatic test apparatus having high property, and its practical effect is great.

[Brief description of drawings]

 FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, and FIGS. 3 and 4 are conceptual diagrams of a conventional test method. In the drawings, 1 is a printed board to be tested, 2 is a printed board for test, 3 is a central processing unit, and 4 is an input / output device.

Claims (1)

[Claims] 1. A bidirectional interface, a unidirectional interface, storage means for storing an interface conversion program, and a microprogram control circuit for loading a program stored in the storage means to perform microprogram control. A printed board to be interface-converted from a signal input from the bidirectional interface by microprogram control and output from the unidirectional interface; a bidirectional interface having the same configuration as the bidirectional interface; and a unidirectional interface. A unidirectional interface in which the transmission / reception relationship is reversed, storage means for storing a test program for generating a test signal and comparing a response signal to the test signal with an expected value to check whether they match or not; Micro program system The control circuit is connected to a test printed circuit board having a microprogram control circuit of the same configuration so as to face each other through the bidirectional interface and the unidirectional interface in a one-to-one relationship, and the memory of the test printed circuit board is stored. The test program stored in the means is loaded into the microprogram control circuit of the test printed board and activated to send a test signal through the bidirectional interface of the printed board under test.
Receiving a response signal from the printed board under test through the unidirectional interface of the test printed board, comparing the test signal with an expected value obtained by interface conversion by the test program, and checking whether or not they match. The automatic test control method is characterized in that the printed circuit board under test is tested by