JPH1068762A - Semiconductor circuit device with built-in a/d converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and rapidly inspect the error in A/D conversion, by outputting the error between the A/D converted digital data and the ideal digital data to the external not through the output command. SOLUTION: The input terminals 1, 4 and an output terminal 7 of a microcomputer 8 are connected with a digital tester. When the analogue voltage for one code, is input to the input terminal 1 from the digital tester simultaneously with the start of the inspection, an A/D converter 2 converts the same to the digital data, and outputs the same to a comparator 6 through a data register 3. The comparator 6 compares the digital data with the ideal digital data input through the input terminal 4 to determine the error, and inputs the same to a digital tester through the output terminal 7. The digital tester judges the quality of a microcomputer 8 including the A/D converter 2, on the basis of the input data error. The operation is repeated, and the measurement is stopped in a stage when no good is judged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor circuit device having an A / D converter capable of converting an analog signal into a digital signal.

[0002]

2. Description of the Related Art Conventionally, an A / D converter inspection circuit disclosed in JP-A-2-67974 is known.

FIG. 2 is a diagram showing a configuration of a conventional microcomputer having a built-in A / D converter. In FIG. 2, 1 is an input terminal for inputting an analog voltage for one code, 2 is an A / D converter for converting the analog voltage input to the input terminal 1 into digital data,
Reference numeral 3 denotes a data register for storing digital data converted by the A / D converter 2, reference numeral 7 denotes an output terminal for outputting the digital data stored in the data register 3 to the outside of the microcomputer, and reference numeral 8 denotes the A / D converter.
This is a microcomputer including the D converter 2 and the like.

[0006] The inspection method of the microcomputer 8 having the A / D converter constructed as described above will be described below.

First, a digital tester (not shown) is used to
The analog voltage for the code is input from the input terminal 1 and A /
The D converter 2 converts the analog voltage for one code into digital data, and stores the converted digital data in the data register 3. The stored digital data is output from the output terminal 7 to the outside of the microcomputer 8 according to an output command, and stored in the memory of the digital tester. A / D
In order to determine the quality of the microcomputer 8 having a built-in converter, it is necessary to perform A / A conversion on a plurality of codes or all codes extracted from the inputtable analog voltage range.
In order to make a determination after measuring the digital data after D conversion, it is necessary to repeat the above operation a plurality of times. After all the measurements are completed, the digital tester judges the quality. Therefore, the same inspection time is required irrespective of non-defective products.

[0006]

In this A / D converter, it is required that a digital tester can easily and quickly check an A / D conversion error.

[0007] The present invention satisfies the above-mentioned requirement, and converts digital data obtained by converting an input analog voltage for one code by an A / D converter and ideal digital data corresponding to the input analog voltage for one code. An error is obtained by comparison, and the error is output from an output terminal without passing through an output instruction, and a pass / fail decision is made at any time by a digital tester. An object of the present invention is to stop the measurement at the stage where it is determined that the product is defective while repeating such an operation a plurality of times, to determine the defective product without performing all the measurements, and to perform the inspection easily and at high speed.

[0008]

According to the present invention, an analog voltage for one code is inputted from a digital tester from one input terminal in FIG.
The analog voltage for one code is converted into digital data by the / D converter, and the converted digital data is stored in the data register 3. The ideal digital data corresponding to the analog voltage for one code from one digital tester
An error is obtained by comparing the digital data converted by the A / D converter 3 and the ideal digital data 4 by the comparator 6 and the error obtained by the comparator 6 is obtained. 7 without going through output instructions
Are output at any time by the output terminal of the digital camera, and the output error is determined by the digital tester as needed. At the same time, a conversion end signal of the A / D converter 2 is output from the output terminal 5 and is sensed by the digital tester to input 1 from the input terminal 1.
The analog voltage for the code is changed to the analog voltage to be input next, and the next measurement is performed.

Thus, the error between the digital data converted by the A / D converter and the ideal digital data corresponding to the analog voltage for one code is output from the output terminal without an output command, and the digital tester outputs the error at any time. Make a pass / fail decision. The measurement is stopped when it is determined that the product is defective while the operation is repeated a plurality of times, and the defective product can be determined without performing the entire measurement, thereby facilitating the inspection easily and quickly. The effect is obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention provides an A / D converter for converting an input analog voltage into digital data, and a digital data converted by the A / D converter. A data register for storing the data, and a comparator for comparing the digital data converted by the A / D converter with the ideal digital data input from the digital tester to determine an error; This is a microcomputer having a built-in A / D converter configured to output an error between the data and the ideal digital data to the outside of the microcomputer without passing through an output command and to judge the quality at any time. This has the effect that inspection can be performed easily and at high speed.

According to a second aspect of the present invention, a first input terminal for inputting an analog voltage and ideal digital data corresponding to the analog voltage input to the first input terminal are input. Input terminal, an A / D converter for converting an analog voltage input to the first input terminal into digital data, digital data converted by the A / D converter, and the second input terminal.
A / D comprising: a comparator for obtaining an error based on ideal digital data input to an input terminal of the A / D converter; and an output terminal for outputting the error obtained by the comparator. This is a semiconductor circuit device having a built-in converter.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a configuration diagram of a microcomputer having a built-in A / D converter. In FIG.
1 is an input terminal for inputting an analog voltage for one code from a digital tester (not shown), 2 is an A / D converter for converting analog data input to the input terminal 1 into digital data, 3 is A A data register 4 for storing digital data converted by the / D converter 2; an input terminal 4 for inputting ideal digital data corresponding to an analog voltage for one code input at the input terminal 1 from a digital tester; A / D converter 2
And an output terminal 6 for outputting the conversion end signal to the outside of the microcomputer, and a comparator 6 for comparing the digital data converted by the A / D converter 2 with the ideal digital data input to the input terminal 4 to obtain an error. Reference numeral 7 denotes an output terminal for outputting an error obtained by the comparator 6 at the time of inspection to the outside of the microcomputer, and reference numeral 8 denotes a microcomputer having the A / D converter 2 and the like built therein.

Next, at the time of inspection, A /
The operation of the microcomputer including the D converter will be described. When inspecting the quality of the microcomputer 8 incorporating the A / D converter, at least the input terminals 1, 4 and the output terminal 7 are connected to a digital tester.

When the test is started, the digital tester inputs an analog voltage for one code to the input terminal 1,
Then, ideal digital data corresponding to the analog voltage for one code input to the input terminal 1 is input to the input terminal 4.

The A / D converter 2 converts analog data input to the input terminal 1 into digital data. The converted digital data is input to the comparator 6 via the data register 3, and when the data conversion is completed, A /
A conversion end signal is output from the D converter 2 to the output terminal 5. The ideal digital data input to the input terminal 4 is also input to the comparator 6.

The comparator 6 compares the digital data converted by the A / D converter 2 with the ideal digital data input to the input terminal 4 to determine an error. The error obtained by the comparator 6 is input to the aforementioned digital tester via the output terminal 7. Then, based on the output of the output terminal 7, the digital tester
The quality of the microcomputer 8 incorporating the / D converter is determined.

Normally, analog voltages for a plurality of types of codes are determined in advance, and depending on whether or not the determined plurality of types of codes are cleared, the final value of the microcomputer 8 incorporating the A / D converter is determined. Is determined.

[0018]

As described above, according to the present invention, the error between the A / D-converted digital data and the ideal digital data is output to the outside of the microcomputer without passing through an output command, and the digital tester is used to determine whether the error is good or bad at any time. Is determined.
While the operation is repeated a plurality of times, the measurement is stopped when it is determined to be defective, and the defective product can be determined without performing the entire measurement, and the A / D conversion inspection can be performed easily and at high speed. Effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a microcomputer including an A / D converter according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a microcomputer incorporating a conventional A / D converter.

[Explanation of symbols]

 1 Analog voltage input terminal for one code 2 A / D converter 3 Data register 4 Ideal digital data input terminal 5 Conversion end signal output terminal 6 Comparator 7 Digital data output terminal

Claims (2)

[Claims] 1. An A / D converter for converting an analog voltage into digital data, a data register for storing digital data converted by the A / D converter, and a digital data converted by the A / D converter And a comparator for comparing the data with the ideal digital data input from the digital tester to obtain an error. The error between the A / D-converted digital data and the ideal digital data is output to the outside without an output command. A semiconductor circuit device having a built-in A / D converter configured to output an output and to judge the quality at any time so that the inspection can be performed easily and at high speed. 2. A first input terminal for inputting an analog voltage and a second input terminal for inputting ideal digital data corresponding to the analog voltage input to the first input terminal.
Input terminal, an A / D converter for converting an analog voltage input to the first input terminal into digital data, and digital data converted by the A / D converter and the second input terminal. A comparator for calculating an error based on the input ideal digital data,
An output terminal for outputting an error obtained by the comparator; and a semiconductor circuit device having a built-in A / D converter.