JP2769166B2 - Electronic circuit inspection equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit inspection apparatus for evaluating the operation of an electronic circuit.

2. Description of the Related Art In order to evaluate a program of an electronic control device including a microcomputer or the like, it is necessary to evaluate the entire control device including a device to be controlled. In practice, a pseudo signal is input to an evaluation board in order to easily perform the evaluation, and the operation is evaluated by executing a program on a development support device called an in-circuit emulator (ICE).

FIG. 4 is a block diagram for explaining inspection of a conventional electronic circuit. The development support device 40 including the emulator board 41 includes an input device 42, a processing device 43, and a display device 44. The input device 42 is, for example, a keyboard for inputting a program or data. A program or the like input from the input device 42 is sent to the processing device 43.
The processing device 43 performs control of the entire development support device 40, assembling processing for converting a source program input from the input device 42 into a machine language, processing for evaluating a program executed on the emulator board 41, and the like. The display device 44 displays a result of processing executed on the emulator board 41 and the like. For example, a CRT device.

The emulator board 41 has a central processing unit (CPU) 41a
And a memory 41b for executing the program and inputting the execution state to the processing unit 43 instead of the control microcomputer (MPU) used in the electronic circuit 47. The program transferred from the processing device 43 is stored in the memory 41b via the bus line bl1. The CPU 41a executes processing according to a program stored in the memory 41b.

A pseudo signal which is an analog signal input to the electronic circuit 47 is generated by the pseudo signal generation circuit 45. As the pseudo signal, for example, a pulse signal having a different amplitude or a repetition period, a predetermined voltage signal, and the like are generated, and the generation conditions thereof are set in the input device 46.

The development support device 40 originally converts a pseudo signal input into digital data in accordance with the procedure stored in the memory 41b, instead of the microcomputer arranged in the electronic circuit 47, and then uses the digital data as a basis. The control operation is performed and a control signal is output to the control target 48.

The development support device 40 stores the processing executed in the emulator board 41, for example, a value obtained by converting a pseudo signal into digital data, the content of a control signal output to the control target 48 to the display device 44, thereby storing the data in the memory 41b. It is determined whether the stored program has been executed normally.

As described above, in developing a conventional program, a pseudo signal for evaluating a program is set in the input device 46, and a control signal is generated based on the pseudo signal. . In these processes, the development support device 40 causes the display device 44 to output the correlation between the input of the pseudo signal and the output of the control signal, for example, to evaluate whether or not the program is normally executed.

However, if the pseudo signal input to the electronic circuit 47 does not match the digital data to be evaluated, for example, if the repetition period, output timing, etc. do not match the numerical values to be evaluated, accurate program evaluation cannot be performed. It is necessary to operate again so that the target digital data is input to the development support device 40. In particular, when it is necessary to generate a large number of spurious signals, generating all of the spurious signals into a signal to be evaluated for a program requires time and effort and causes a reduction in program development efficiency. Becomes

Therefore, an object of the present invention is to solve the above-described problem, and provides an electronic circuit inspection apparatus that automatically corrects an analog signal input to the electronic circuit so that the analog signal becomes a predetermined digital signal. It is in.

Means for Solving the Problems The present invention is an electronic circuit inspection device that receives an analog signal and derives a digital signal corresponding to the analog signal, wherein an inspection signal used to give an analog signal to the electronic circuit is provided. A test signal generating means to be generated, a digital signal from the electronic circuit is given, a deviation detecting means to detect a deviation between this digital signal and an analog signal from the test signal generating means, and an output of the deviation detecting means Response means for correcting an analog signal from the test signal generating means, whereby a predetermined digital signal is derived from an electronic circuit in accordance with the analog signal from the test signal generating means. An electronic circuit inspection device.

In the present invention, the electronic circuit receives an analog signal and outputs a digital signal corresponding to the analog signal. The test signal generating means generates a test signal and supplies an analog signal to the electronic circuit based on the test signal. The deviation detecting means detects a deviation between the digital signal output from the electronic circuit and the analog signal from the inspection signal generating means.
Then, the correcting means corrects the analog signal from the inspection signal generating means based on the output from the deviation detecting means. By this correction, a digital signal corresponding to the analog signal from the inspection signal generating means is derived from the electronic circuit.

Embodiment FIG. 1 is a block diagram for explaining an electronic circuit inspection apparatus according to an embodiment of the present invention. The operation will be described below. The electronic circuit 1 is a circuit whose operation is inspected by an electronic circuit inspection device, and includes a CPU 1a, a memory 1b, a counter 1c, an input / output circuit (I / O) 1d, and the like. Done via line bl.
The condition of the signal waveform of the pseudo signal input to the electronic circuit 1 is as follows:
The information is set by the input device 2 realized by a keyboard or the like, and is input to the processing circuit 3.

The conversion circuit 4 converts the analog voltage value output from the processing circuit 3 into a signal waveform set in the input device 2 and outputs the signal waveform. For example, when the conversion circuit 4 is a voltage / frequency conversion circuit, the conversion circuit 4 outputs a signal such as a square wave or a sine wave. When the conversion circuit 4 is a voltage / frequency conversion circuit that outputs a square wave, the counter 1c of the electronic circuit 1 counts the number of pulses of the input signal. The CPU 1 performs a control operation in accordance with a control program stored in the memory 1b based on the numerical value counted by the counter 1c, and outputs a control signal to the control target 5.

The value counted by the counter 1c is inverted by the data latch 6 via the input / output circuit 1d and is temporarily stored. The numerical value stored in the data latch 6 is
And whether the condition set in the input device 2 is matched is determined by a process described later. If not, the correction process is performed.

Next, the operation of the processing circuit 3 will be described. The data set in the input device 2 is transmitted to the data conversion circuit 3a.
Is input to The data conversion circuit 3a performs conversion for matching the unit system between the set value in the input device 2 and the analog signal output from the conversion circuit 4. The output signal can be corrected in the processing circuit 3 regardless of the unit system of the analog signal output from the conversion circuit 4 by the data conversion in the data conversion 3a. The output of the data conversion circuit 3a is input to the addition circuit 3b, added to the output of the integration circuit 3c, and sent to the digital / analog conversion circuit 3d. The digital / analog conversion circuit 3d converts the digital amount into an analog amount, that is, an analog voltage value.
Output to

The count value counted by the counter 1c is input to the input circuit 3e via the data latch 6. Input circuit 3e
Is an input buffer circuit. The output of the input circuit 3e is sent to the data conversion circuit 3f, where data conversion is performed. This data conversion is a conversion process for matching the unit system of the count value counted by the counter 1c with the unit system of the setting data in the input device 2. The data converted by the data conversion circuit 3f is compared with the set data set by the input device 2 in the comparison circuit 3g, and their deviation is input to the integration circuit 3c, and the deviation amount is integrated, that is, integrated. . The correction value integrated in the integration circuit 3c is added to the output value of the data conversion circuit 3a in the addition circuit 3b, and is corrected in the processing circuit 3 so that the set value set in the input device 2 is counted by the counter 1c. .

FIG. 2 is a flowchart for explaining the processing of this embodiment. Hereinafter, the processing of each step will be described. At step n1, the set value input at the input device 2 is input to the processing circuit 3. In step n2, an output initial value is calculated and determined based on the set value input to the data conversion circuit 3a. This output initial value is a digital value corresponding to a numerical value set in the input device 2. When the output initial value is determined in step n2, step n3
In, an output value to be output to the digital / analog conversion circuit 3d is calculated. The output value is obtained by adding the output initial value and the correction value from the integration circuit 3c as shown in the first equation.

Output value = output initial value + correction value (1) When the output value is calculated in step n3,
At n4, the output value is sent to the conversion circuit 4, and the conversion circuit 4 generates a pseudo signal. When a pseudo signal is generated, the pseudo signal is output to the electronic circuit 1 in step n5.

When the pseudo signal is output to the electronic circuit 1 at step n5, the count value counted by the counter 1c is input to the processing circuit 3 via the data latch 6, and the comparison circuit 3g
Calculates the deviation value Δx. When the deviation Δx is calculated in step n6, the process proceeds to step n7, where it is determined whether or not the deviation Δx is zero. 0
If not, the process proceeds to step n8, and it is determined whether or not the absolute value of the deviation value Δx is within a predetermined allowable value K. If the absolute value of the deviation Δx is not within the allowable value, the process proceeds to step n9, and the number of corrections already performed is
It is determined whether it is 200 times or more. If the number is less than 200, the process proceeds to step n10, where the calculation of the correction value in the adding circuit 3b is performed.

When the absolute value of the deviation Δx falls within the allowable value K by the above correction processing, the process proceeds from step n8 to step n11, and
It is determined whether or not the number of corrections already performed within the allowable range is five or more. If the number of corrections is less than five, the above-described correction processing is further performed.

If the deviation value Δx is 0 in step n7, if the number of corrections is 200 or more in step n9, or if the number of corrections is 5 or more in step n11, the correction process ends and the process proceeds to step n12. . At step n12, the operation result of the electronic circuit 1, for example, the counter 1c
Is input. In step n13, the calculation result input in step n12,
The set values set in the input device are output to, for example, a display device.

FIG. 3 is a block diagram of an electronic circuit inspection apparatus according to another embodiment of the present invention. 3, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

Data conversion circuit 7a, addition circuit 7b, integration circuit 7c, digital / analog conversion circuit 7d and input circuit 7e of processing circuit 7
Is a data conversion circuit 3a, an addition circuit 3b, an integration circuit 3c, a digital / analog conversion circuit 3d and an input circuit in FIG.
Since the same operation as 3e is performed, the description is omitted.

The difference between the other embodiment shown in FIG. 3 and the embodiment shown in FIG. 1 is that the output of the input circuit 7e is input to the negative input terminal of the comparison circuit 7g and the input is input to the positive input terminal of the comparison circuit 7g. The point is that the reference value is input via a reference value generation circuit 7h that generates a reference value corresponding to the set value set in the device 2. The reference value is a detection value in the electronic circuit 1 corresponding to the set value set in the input device 2. Accordingly, the processing circuit 7 performs a correction operation so that the numerical value detected by the electronic circuit 1 becomes the same as the reference value.

Next, in order to describe the configuration shown in FIG. 3 in more detail, specific numerical values will be described. The control target 5 is, for example, an internal combustion engine.
A signal simulating the state of rotation at 00 rpm is sent to the electronic circuit 1.
Will be described.

The speed of the internal combustion engine is 3000 rpm, 3000 revolutions per minute.
3000/60 = 50 rotations per second. Now, assuming that a signal of one pulse is input to the electronic circuit 1 for each rotation angle of 1 degree, since one rotation is 360 degrees, the repetition frequency to the electronic circuit 1 is set to 3000 [rpm] in order to set the established value to 3000 [rpm]. That is, the repetition frequency of the output pulse of the conversion circuit 4 needs to be 18000 Hz as determined by the second equation.

When the conversion characteristic expression of the conversion circuit 4 is expressed by the third expression, the input voltage of the conversion circuit 4 needs to be 1.8 V in order to make the repetition frequency of the output pulse of the conversion circuit 4 18000 Hz.

Output pulse repetition frequency [Hz] = 10 ⁴ × input voltage [V] (3) If the conversion characteristic equation of the digital / analog conversion circuit 7d is the fourth equation, the digital / analog conversion circuit 7d
In order to set the output voltage to 1.8 V, the input digital value to the digital / analog conversion circuit 7d needs to be 720. This digital value becomes the output initial value. Therefore,
The data conversion circuit 7a is set to 300 [rpm] by the input device 2.
To a digital value of 720.

Output voltage [V] = set value × 0.0025 [V] (4) Next, when the electronic circuit 1 counts the number of revolutions of the internal combustion engine, the minimum bit (LSB) of the counter 1c is 5 [rpm]. Then, the value counted by the counter 1c is the fifth
It is the value calculated by the formula.

Count value = number of rotations / 5 (5) Therefore, the set value at input value 2 is 3000 [rpm].
, The count value in the counter 1c is 600
Should be.

However, even when the output initial value 720 is output from the data conversion circuit 7a, the count value of the counter 1c does not become 600 due to an error due to processing in the electronic circuit 1 (an error due to analog / digital conversion, for example). A deviation value Δx is generated. Therefore, a correction value for canceling the deviation value Δx is calculated by the sixth equation.

For example, when Δx = 10, that is, when the count value of the counter 1c is 610, the correction value is 12 from Expression 6. By adding this correction value to the output initial value in the adding circuit 3e, the deviation value generated in the counter 1c is corrected to be zero.

Actually, in order to prevent over-correction, a value of about 0.3 is selected for 1.2 which is a coefficient of the sixth equation, and fine adjustment is performed by a plurality of correction processes.

As described above, according to the present invention, the analog signal input to the electronic circuit and the digital signal detected in the electronic circuit are automatically corrected so as to coincide with each other. Can be performed more accurately, the work time for program evaluation can be reduced, and work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an electronic circuit inspection apparatus according to one embodiment of the present invention, FIG. 2 is a flowchart for explaining the processing of this embodiment, and FIG. FIG. 4 is a block diagram for explaining an electronic circuit detection apparatus according to an embodiment of the present invention, and FIG. 4 is a block diagram for explaining a conventional electronic circuit inspection. 1 ... Electronic circuit, 2 ... Input device, 3 ... Processing circuit, 4
…… Conversion circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01R 31/28-31/3193 G01R 31/26 G01R 31/00 H03M 1/00-1/88

Claims (1)

(57) [Claims] 1. An inspection apparatus for an electronic circuit which receives an analog signal and derives a digital signal corresponding to the analog signal, wherein: an inspection signal generating means for generating an inspection signal used to supply the electronic circuit with the analog signal. A digital signal from the electronic circuit is provided, a deviation detecting means for detecting a deviation between the digital signal and an analog signal from the test signal generating means, and a test signal generation in response to an output of the deviation detecting means. Means for correcting an analog signal from the means, whereby a predetermined digital signal is derived from the electronic circuit in accordance with the analog signal from the test signal generating means. apparatus.