JPS58111764A - Testing method of printed board - Google Patents

Abstract

PURPOSE:To enable debugging with an IC kept packaged by having a test signal inputted into the IC after a hold signal is inputted into a hole terminal of the IC to make the output terminal thereof electrically inactivated with a high impedance. CONSTITUTION:An IC 11 with a hold terminal is packaged on a printed board 10 and has a plurality of terminals 12 comprising a normal input/output terminal, a power source terminal and the like and a testing hold terminal 13. A test signal from a tester 14 and a hold signal are fetched through an IC connection probe 15. In the debugging of the board 10, the power source of the board 10 is turned off and a probe 15 is set to terminals 12 and 13 to input the hold signal into the terminal 13. Then, when the power source is closed to the board 10, all the output terminals of the IC are made inactivated electrically with a high impedance. Under such a condition, when a test signal of the tester 14 is inputted into the terminal 12, debugging can be done without causing competition between the test signal and output signals of the IC 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed circuit board testing method that allows hardware debugging of a printed circuit board on which an integrated circuit (hereinafter referred to as an IC) is mounted to perform debugging with the IC mounted thereon. It is something.

Conventionally, in order to debug a printed circuit board, as shown in FIG. Debugging is performed by removing the tester C2, inserting a test probe 4 into the tester C socket 3, and supplying each test signal from an external test device (hereinafter referred to as a tester) 5 via the probe 4. A method was taken.

By the way, currently, in the assembly work of mass-produced products, automatic insertion machines are used for components such as ICs, and are extremely efficient, but automatic insertion machines cannot be used for IC sockets. When pouring solder onto a printed circuit board, the flux may seep into the pins of the IC socket, causing poor contact.

To do this, it is necessary to perform several types of automatic soldering and cleaning, then manually perform retrofit work, and then after manual soldering, a work process is required in which the flux adhering to the solder surface of the printed circuit board is cleaned. Therefore, even if there is only one C-socket in the printed circuit board, the increase in man-hours associated with it cannot be ignored.

In this way, when using a tester to debug the hardware on a printed circuit board, if the test signal from the tester is input to the board via the IC socket on the board, the number of man-hours required for mounting the IC socket will increase. Also, there is a need for a test method that allows debugging without using an IC socket and with the IC mounted directly on a printed circuit board, since poor contact may occur due to flux or the like.

The present invention has been made in view of these points, and its purpose is to enable debugging by directly inputting test signals from a tester to the terminals of an IC mounted on a printed circuit board, without inputting them through an IC socket. The purpose of this invention is to provide a method for testing printed circuit boards.

In order to achieve such an object, the present invention provides an integrated circuit board mounted on a printed circuit board that receives test signals from a tester.
A hold terminal is provided at C, and a hold signal is inputted to the hold terminal prior to the test signal from the tester to make the output terminal of the IC high impedance and electrically inactivated, and then the test signal is input to the hold terminal. It is designed to be input directly to the IC.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is an explanatory diagram showing a printed circuit board testing method according to the present invention. In the same figure, reference numeral 10 denotes a printed circuit board similar to the conventional one, on which various ICs (not shown) and a hold terminal C11 which inputs signals from a tester to be described later are mounted. has a plurality of terminals 12 connected to normal input/output terminals, a power supply terminal, etc., and a hold terminal 13 for testing.
By inputting a hold signal from a tester, which will be described later, all the output terminals among the plurality of terminals 12 are set to high impedance. 14 is a tester that outputs various test signals and hold signals necessary for debugging the hardware on the printed circuit board 10, and signals such as test signals and hold signals from this tester 14 are connected to the circuit C. glove 15
taken out through. Then, during the test, the IC connection probe 15 is held at each terminal 12 of the terminal C11.
By connecting the hold terminal 13 to the hold terminal 13, the hold signal is constantly inputted to the hold terminal 13 from the hold signal output terminal 16 of the tester 14 via the probe 15, and each test signal is also input to each terminal 12. The signal is input from the output terminal 17. In addition,
15a is a cable of the ICeC inheritance lobe 15.

Therefore, when debugging a printed circuit board, after turning off the power to the printed circuit board 10, the IC connection probe 15 to which the hold signal from the tester 14 is output is connected to each terminal 12 of the hold terminal C11 and the hold terminal 1.
3 and input this hold signal to the hold terminal 13. When the printed circuit board 10 is powered on, the circuit C11 receives a hold signal from the tester 14, and all of its output terminals become high impedance and are electrically inactivated. In this state, if a test signal is inputted from the tester 14 via the probe 15 to each terminal 12 of the IC1i with a hold terminal, only the test signal from the tester 14 will be inputted to each terminal of this IC11. , tester 14
There is no risk of conflict between the test signal of the IC and the output signal of the IC with a hold terminal, causing runaway of the circuit on the printed circuit board or destruction of the circuit elements.

After the tester 14 has finished debugging the circuit on the printed circuit board 10, the power to the printed circuit board 10 is turned off.
Thereafter, the IC connection probe 15 is removed and debugging is completed.

In this way, the IC 11 with a hold terminal is configured as the mounted IC on the printed circuit board 10, and the hold signal is inputted to the hold terminal 13 of the device C11 prior to the test signal from the tester 14, and the output terminal of the device C11 is controlled. By setting the impedance to zero, this circuit C11 enters a hold state, and the test signal of the tester 14 and the output signal of the circuit C1l with a hold terminal do not conflict, and the printed circuit board 1
The printed circuit board can be debugged with the hold terminal C11 mounted on the board.

As explained above, according to the test method of the present invention, when debugging the hardware of a printed circuit board, signals from the tester are input directly through the terminals of the IC mounted on the board without going through the C socket. This eliminates the increase in man-hours and contact failures caused by flux, which are required in the conventional IC socket mounting process, thereby simplifying product assembly work and improving quality.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing a conventional printed circuit board testing method.
FIG. 2 is an explanatory diagram showing an embodiment of the printed circuit board testing method according to the present invention. 10...Printed circuit board, 11...C with hold terminal (integrated circuit), 13...Hold terminal, 1
4...External test equipment X15...IC connection probe, 16...Hold signal output terminal. =7-

Claims (1)

[Claims] In a printed circuit board configured with multiple integrated circuits mounted, a hold terminal is provided on the integrated circuit that inputs the signal from the external test equipment, and the signal from the external test equipment is input to the terminal including the hold terminal of this integrated circuit. Connect the probe to be tested, input a hold signal to the hold terminal prior to the test signal from the external test equipment, make the output terminal of the integrated circuit high impedance, electrically inactivate it, and then apply the test signal. A method for testing a printed circuit board, characterized in that debugging is performed by inputting information to the integrated circuit.