JPS6269172A - Test instrument for integrated circuit - Google Patents

Abstract

PURPOSE:To identify the presence or absence of error and to enable the restart of error display and error count programs after occurence of the error, by monitoring the execution time of a self-diagnosing program. CONSTITUTION:A programming is made so that a self-checking program is started at the time that a clock pulse is inputted at the input terminal 2 of a microprocessor, and the self-diagnosing program is stored in a program memory. If an execution termination signal of the self-diagnosing program is not outputted at a terminal 4 at the time point that a time measurement signal is outputted at the output terminal 3 of a timer, it is decided that an error has occured, and an error signal is outputted at a terminal 5 through an inverter circuit and an AND circuit. The error signal is inputted to an error counter and an error display circuit to count and displays the error. The error signal is inputted at terminals 1, 2 through an OR circuit, and enables the timer reset and the restart of a self-diagnosing program.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a test device K that is capable of displaying errors, counting errors, and resuming execution of a self-diagnosis program in a functional test using a self-diagnosis method for a microprocessor. It is.

[Conventional technology]

In a commonly performed functional test of a microprocessor, various instructions are executed while checking whether the logic of all output terminals matches expected values. Although this method allows functional testing with a high defect detection rate, it requires a large testing device and is not suitable for simple testing.

On the other hand, the conventional self-diagnosis method for microprocessor function testing is extremely superior in terms of the cost of the test machine, the weight of the test machine, and the ease of handling, but it has the disadvantage of being impractical. If an error occurs during execution of the self-diagnosis program, it may jump to an unintended program address or execute the wrong command. There are many cases where you can't go back. That's why the error occurred.'
x It is not possible to notify the outside world of the microprocessor or to restart the self-diagnosis program.

As mentioned above, in the conventional self-diagnosis function test, it is not possible to display the error, count the number of steps, or restart the program after an error occurs, so it is not practical.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a complete test device that enables error display, error counting, and program restart after an error occurs, which are problems in microprocessor function tests using conventional self-diagnosis methods.

[Summary of the invention]

The present invention is characterized in that the presence or absence of errors is completely identified by observing the execution time of the self-diagnosis program in the best possible test using the self-diagnosis method of the microprocessor. According to the present invention, even if an error occurs, the conventional method cannot notify the outside of the microprocessor of the presence or absence of an error, and nine points can be solved. [Embodiment] FIG. 1 shows an embodiment of the present invention. The clock pulses generated by the clock generation circuit are input to all timers and the -r microprocessor. The measurement time of the timer is set to the execution time of the self-diagnosis program required if no error occurs. 1 is a reset input terminal of the timer, and ko is a reset input terminal or an interconnected input terminal of the microgrossing device.

Programming is performed so that execution of the self-diagnosis program starts when a pulse is input to λ. The program memory is a memory that stores a self-diagnosis program. 3 is an output terminal for a time measurement signal of a timer, and ≠ is an output terminal for an execution end signal of a self-diagnosis program. !
is an error signal output terminal. If the end signal is not output to the terminal No. 3 while the time measurement signal is output to the terminal No. 3, it is determined that an error has occurred, and the inverter circuit and AN
The D circuit generates error detection at the evening terminal.

This error signal is input to an error counter and an error display circuit to count and display errors. Input the measurement signal to terminal 2 through the 0 circuit, reset the timer and restart the self-diagnosis program. The time relationship of each signal is as shown in FIG.

In the circuit of the embodiment shown in FIG. 1, it is necessary to make the pulse width of the end signal a little wider than the pulse width of the time measurement signal.

The switch r is used to manually start execution of the self-diagnosis program.

If you want to run the self-diagnosis program only seven times, there is no need to return the time measurement signal to the reset signal.

General ((If an error occurs, the execution time of the self-diagnosis program will naturally change because the program jumps to an unintended program address or executes the wrong command.) In order to change the flow of the program, it is desirable to intentionally change the execution item number of the program using a jump instruction or the like when all errors are detected in the self-diagnosis program.

The maximum number of errors that can be counted within the execution time of the self-diagnosis program is one. Therefore, the self-diagnosis program can be divided into a plurality of blocks to improve the error detection ability. In this case, it is necessary to set the program blocks to be executed by seven blocks each time the microprocessor reset signal is input. It is also necessary to change the setting time of the timer in accordance with the execution time of each block by changing the timer to a brise scale. Alternatively, by adding an extra instruction to a block that lacks execution time, the execution time of all blocks can be made the same, and the set time of the timer can be fixed.

The above explanation has been about microprocessor tests, but the basic idea can also be applied to tests of various computers and various processors.

〔Effect of the invention〕

As explained above, the test device of the present invention improves the conventional test device based on the self-diagnosis method for microprocessors, which was extremely impractical, by adding only a few parts, and is capable of displaying errors, counting errors, and detecting errors when they occur. Since it is now possible to restart the program, it has become possible to obtain satisfactory performance as a simple test device.

[Brief explanation of drawings]

FIG. 7 shows an embodiment of the present invention. (al is the test circuit, (
bl is the timing of each signal. /...Timer reset input terminal, λ...Microprocessor reset input terminal or interwoven input terminal, 3...Timer time measurement signal output terminal, Hiro...Self-diagnosis program execution end signal output Terminal!
...Error signal output terminal, 6.At the start of execution of the self-diagnosis program, 7.Signal when an error occurs, g.
...Manual start switch for self-diagnosis program.

Claims (1)

[Claims] In a functional test using a microprocessor self-diagnosis method, a self-diagnosis program is programmed to change the execution order of the programs if an error occurs during execution of the self-diagnosis program, and a microprocessor means for outputting an end signal to the outside of the program; time measuring means for measuring time from the start of execution of the program and outputting a time measurement signal when the execution time of the program has elapsed when no error occurs; means for counting an error when an end signal is not output at the time the time measurement signal is output;
1. An integrated circuit testing device comprising means for resetting a time measurement circuit and restarting execution of a self-diagnosis program after outputting a time measurement signal.