JP2000066918A - Scanning test device for circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to execute a test in system operation by widely developing a scanning test for a circuit board in a computer system. SOLUTION: The circuit board scanning test device is provided with plural circuit boards 1, 2 connected to a bus, selectors 3, 4 connected to respective circuit board 1, 2 and allowed to deter-mine whether the boards 1, 2 are to be tested or not in accordance with a test signal from an external controller 7 and a circuit for providing test pattern signals from the controller 7 to respective boards 1, 2 and sending output signals corresponding to the test pattern signals from the boards 1, 2 to the controller 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for testing a circuit board in a computer system, and more particularly to an apparatus for performing a scan test on a circuit board.

[0002]

2. Description of the Related Art A computer system is composed of many circuit boards, and it is necessary to constantly check that these circuit boards operate normally. This circuit board is
Also includes those configured as modules. Therefore, conventionally, a test is performed for each of a plurality of circuit boards incorporated in the computer system by using the time when the computer system is stopped.

In a computer system having a modular configuration, a test is performed by mounting a module using a special bridge IC or a test module.

[0004]

As described above, the conventional circuit board test is not performed during the operation of the computer system. In addition, in order to perform a scan test in a system using a plurality of substrates as modules, it is necessary to mount a special bridge IC on the module. Therefore, the configuration of the scan chain is limited, and only one module can be accessed on the same bus.

The present invention has been made in view of the above points, and has as its object to develop a circuit board scan test in a computer system more widely.

[0006]

According to the present invention, a plurality of circuit boards coupled to a bus are provided. Each of the circuit boards is provided in accordance with a test signal from an external controller. And a selector for determining whether or not to perform the test, and a test pattern signal from the external controller to the circuit board, and an output signal from the circuit board according to the test pattern signal sent to the external controller. Provided is a circuit board scan test apparatus provided with a circuit.

[0007]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention. In this figure, 10
Is a circuit board on which modules 1 and 2 are assembled.
Selectors 3 and 4 are connected to the modules 1 and 2, respectively, and the modules 1 and 2 are connected to each other by a bus 5.

[0008] Output signals from the tests of the modules 1 and 2 are taken out from one of the selectors 3 and 4 to the external controller 7 via the parallel / serial converter 6.

In this test, the following operation is performed. First, the test pattern signals TCLK and TMS are directly supplied to the modules 1 and 2 from the external controller 7 storing the scan test program. Then, based on this, the modules 1 and 2 supply the operation control signal SEL of the selectors 3 and 4 to the selectors 3 and 4, and also supply the operation control signal SEL to the external controller via the parallel / serial converter 6. When the module 1 or 2 receives the test signal TDI from the external controller 7 via the selectors 3 and 4, the module 1 returns the test output TDO to the external controller 7 via the selectors 3 and 4.

FIG. 2 shows the contents of the data chain selecting operation of the selectors 3 and 4. Selector 3, 4
Switches the boundary scan chain. Switching is performed in accordance with the level (H, L) of the selection signal SEL from the modules 1 and 2. If H, the test signal TDI is sent to the output terminal as it is as TDO. The module test signal MOD-TDI is sent to the external controller 7 as the module test signal MOD-TDI.

[0011] Briefly, the selectors 3 and 4 operate according to the level of the selection signal SEL.
To return the test signal from the external controller to or from the external controller with or without the module.

FIG. 3 shows a test input / output operation of each of the modules 1 and 2. In this example, a temporary BSDL file having a uniform specification is formed in each module. Therefore, each module has a bypass instruction, ID
The read command is equal, and the ID code length is also equal and is H bits. Each module has three registers IR and a bypass register Bypass (not shown).
-R and ID-R for identification data.
The type of module and the mounting position in which slot the module is mounted can be known from the identification data of DR.

It is necessary to detect whether or not the module is mounted in a hardware manner, and it is necessary to select a scan chain when the module is not mounted based on the detection result. ) Is provided.

If the type of the module is determined by reading the ID code in this way, test data is created using a BSDL file corresponding to the type, and a normal test is performed.

FIG. 4 is a block diagram showing the configuration of the second embodiment of the present invention. This embodiment corresponds to a boundary scan test, and the selectors 3 and 4 switch the boundary scan chain.
The chains are switched according to the select signals SEL from the modules 1 and 2.

In this embodiment, the service processor 8 controls the data scan execution timing. The service processor 8 has a control unit and a memory. The control unit probes a module on the bus 5 by a microprogram stored in the memory to know the type and mounting position of the module.

When the modules 1 and 2 are mounted on the circuit board 10, select signals are given from the modules 1 and 2 to the selectors 3 and 4, whereby the selectors 3 and 4 select a scan chain. Next, the service processor 8 accesses the bus 5 based on the microprogram to obtain the mounting position of the module and a unique identification ID. The service processor 8 sends the mounting position and the unique identification ID to the external controller 7. External controller 7
Creates test data based on this and performs a scan test.

[0018]

As described above, according to the present invention, a selector determines whether or not to test a plurality of circuit boards coupled to a bus in accordance with a test signal from an external controller. Since the test pattern signal is supplied to the external controller from the circuit board in accordance with the test pattern signal, a scan test of the circuit board in the computer system can be more widely developed. That is, creation of a test module becomes unnecessary, manual switching of scan chains becomes unnecessary, and a special bridge IC becomes unnecessary. Then, a test between boards through a bus can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of a selector in the embodiment of FIG.

FIG. 3 is an explanatory diagram showing an operational relationship between a module and an external controller in the embodiment of FIG. 1;

FIG. 4 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

[Explanation of symbols]

 1, 2 module 3, 4 selector 5 bus 6 parallel / serial converter 7 external controller 8 service processor 10 circuit board

Claims (2)

[Claims] A plurality of circuit boards coupled to a bus; a selector provided for each of the circuit boards, for determining whether or not to test the circuit board in response to a test signal from an external controller; A circuit board scan test apparatus comprising: a circuit that supplies a test pattern signal from the external controller to the board and sends an output signal from the circuit board to the external controller in accordance with the test pattern signal. 2. The circuit board scan test apparatus according to claim 1, further comprising: a service processor configured to generate a signal for testing the circuit board by receiving the test pattern signal from the external controller. Scan test equipment for circuit boards.