CN118214418A

CN118214418A - Analog-to-digital conversion AD574 testing device and method based on single chip microcomputer

Info

Publication number: CN118214418A
Application number: CN202410291565.3A
Authority: CN
Inventors: 黄磊; 杨彬彬; 周骋; 胡伟
Original assignee: State Run Wuhu Machinery Factory
Current assignee: State Run Wuhu Machinery Factory
Priority date: 2024-03-14
Filing date: 2024-03-14
Publication date: 2024-06-18

Abstract

The invention relates to the technical field of AD574 test, in particular to a test device and a test method of AD574 based on analog-to-digital conversion of a singlechip, wherein the test device comprises an industrial personal computer; the singlechip is connected with the industrial personal computer through an RS232 serial port; the decoding control circuit is connected with the singlechip; an analog voltage input circuit; and the analog switch circuit is connected with the analog voltage input circuit and the AD574 to be tested. The invention provides the test device and the test method for the AD574 based on the analog-to-digital conversion of the singlechip, which can realize the screening and fault detection of the components of the AD574, greatly reduce the waste in the production process, save the resources and reduce the cost; and the structure is simple, the work is reliable, the applicability is strong, and the practicability is good.

Description

Analog-to-digital conversion AD574 testing device and method based on single chip microcomputer

Technical Field

The invention relates to the technical field of AD574 test, in particular to a single-chip microcomputer-based analog-to-digital conversion AD574 test device and a test method.

Background

The AD574 is used as an analog-to-digital conversion chip, often used as an analog signal acquisition medium in airborne equipment and used for analog-to-digital conversion, and the accuracy directly influences a post-circuit, namely a CPU (central processing unit) and the like to make a correct instruction, so that the chip is generally used as a peripheral of the CPU. The general airborne equipment has a self-checking function, can carry out self-checking on all functions after being electrified, and can give an alarm when errors occur. The AD 574-based analog-to-digital conversion circuit includes, in addition to the main AD574 chip, many types of resistor, capacitor, crystal oscillator, operational amplifier, and other components, and generally performs self-test as a whole, but only self-test can determine whether there is a problem, but specifically which component has a problem and what problem is, and cannot be determined by self-test of on-board equipment, so that the chip needs to be further detached from the product for separate test. In addition, the self-checking program of the airborne equipment is mastered by a manufacturer, and the self-checking program can not be changed by a repair manufacturer to perform fault location; on the other hand, the self-checking may only detect one state, but more than one state in actual working, if the chip is good in the self-checking state and fails in normal working, the on-board product may report a series of fault codes, and the operator cannot analyze where to go out from a plurality of fault codes.

In actual product repair, there are two cases where such chips need to be tested separately off-board the entire on-board equipment for screening and fault diagnosis: 1. the chip may be damaged, and whether the chip is damaged or not and can be used next is further determined; 2. when the chip needs to be replaced, when a new chip is acquired, the acquired chip needs to be confirmed to be normal in function.

The single test is mainly to adopt a singlechip to control the time sequence logic of the AD574, and the program can be written by itself, so that the flexibility is high, and the functions of all pins of the AD574 can be traversed once, thereby realizing the function test of the device.

However, the existing screening is generally to perform appearance inspection on the internal circuit of the chip by optical detection means, and the functional test on the complex chip is lacking. Or special equipment for purchasing is needed to test the chip, the cost is relatively high, the volume is large, the equipment is generally fixed, the power wiring is relatively complex, and the equipment is not practical and portable.

Disclosure of Invention

In order to solve the technical problems, the invention provides a test device and a test method for analog-to-digital conversion AD574 based on a singlechip.

The technical problems to be solved by the invention are realized by adopting the following technical scheme:

a test device for analog-to-digital conversion AD574 based on a single chip microcomputer comprises:

the industrial personal computer adopts an upper computer test program as a man-machine interaction tool and is used for setting a test state and displaying a test result;

The singlechip is connected with the industrial personal computer through an RS232 serial port and is used as a processor for running a program, processing information and controlling each module to work cooperatively;

The decoding control circuit is connected with the singlechip and used for decoding an address line, a data line and a control output which are output by the singlechip and controlling the AD574 to be detected by the decoded control output;

the analog voltage input circuit is used for respectively conditioning eight paths of analog voltages so as to meet the requirement of test voltages;

The analog switch circuit is connected with the analog voltage input circuit and the AD574 to be tested, is controlled by the singlechip and the decoding control circuit and is used for selecting one analog voltage from eight analog voltages as the voltage to be tested.

Preferably, the industrial personal computer comprises analog-to-digital conversion time sequence control function software, serial port interrupt function software and serial port transmission function software.

Preferably, the singlechip comprises a singlechip, a MAX708 watchdog chip and a MAX232 serial port protocol chip.

Preferably, the single chip microcomputer comprises an address line and a data line which are multiplexed by AD 0-AD 7 and are connected with the decoding control circuit, the analog switch control circuit and the address line and the data line of the AD574 to be detected, a control pin 21 connected with a pin 28 on the AD574 to be detected, a control pin 22 connected with a pin 3 on the AD574 to be detected, and a control pin 23 connected with the decoding control circuit.

Preferably, the decoding control circuit is composed of a latch 74HC373 chip, and latches control signals of two control pins A0 and RC.

Preferably, the latch 74HC373 chip includes pin 11 connected to control pin 23, pin 19 connected to pin 4 on the AD574 to be tested, and pin 18 connected to pin 5 on the AD574 to be tested.

Preferably, the analog voltage input circuit is formed by a DG508 chip, and the DG508 chip includes a pin 1, a pin 15, and a pin 16 connected to the analog switch circuit.

Preferably, the analog switch circuit includes a pin 2 connected to a pin 1 on the analog voltage input circuit, a pin 10 connected to a pin 15 on the analog voltage input circuit, and a pin 7 connected to a pin 16 on the analog voltage input circuit.

A test method of analog-to-digital conversion AD574 based on a single chip microcomputer is applied to the test device of analog-to-digital conversion AD574 based on the single chip microcomputer, and comprises the following steps:

(1) After an upper computer test program in the industrial personal computer starts to test, carrying out a singlechip handshake test;

(2) After the handshake of the singlechip is successful, setting A0=0 and RC=0 for a control pin corresponding to the AD574 to be tested;

(3) The decoding control circuit generates corresponding control output to control the AD574 to be detected;

(4) Setting an analog voltage path, and setting CS=0 for a control pin corresponding to the AD574 to be tested;

(5) The decoding control circuit generates corresponding control output to control the AD574 to be tested and the analog switch control circuit;

(6) The AD574 to be tested starts 12-bit data conversion;

(7) The singlechip inquires whether an STS pin of the AD574 to be tested is 1, if so, the analog-to-digital conversion is incomplete, the standby is needed, and if so, the analog-to-digital conversion is completed, and if so, the analog-to-digital conversion is performed downwards in sequence;

(8) Control pins corresponding to the AD574 to be tested are set to A0=0, RC=1 and CS=0;

(9) The decoding control circuit generates corresponding control output to control the AD574 to be detected;

(10) The singlechip receives high 8-bit data converted by the AD574 to be detected through a data line and stores the data;

(11) Control pins corresponding to the AD574 to be tested are set to a0=1, rc=1, and cs=0;

(12) The decoding control circuit generates corresponding control output to control the AD574 to be detected;

(13) The singlechip receives low-4-bit data converted by the AD574 to be detected through a data line and stores the data;

(14) The singlechip integrates the high 8-bit data and the low 4-bit data, and uploads the result to the upper computer test program through the serial port;

(15) The upper computer test program compares whether the received data is correct, if the received data is correct, the report test is correct, and if the received data is incorrect, the report test is wrong.

The beneficial effects of the invention are as follows:

the invention provides the test device and the test method for the AD574 based on the analog-to-digital conversion of the singlechip, which can realize the screening and fault detection of the components of the AD574, greatly reduce the waste in the production process, save the resources and reduce the cost; and the structure is simple, the work is reliable, the applicability is strong, and the practicability is good.

Drawings

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

FIG. 1 is a block diagram of the apparatus of the present invention;

FIG. 2 is a schematic diagram of a monolithic circuit according to the present invention;

FIG. 3 is a schematic diagram of a single-chip microcomputer according to the second embodiment of the present invention;

FIG. 4 is a schematic diagram of a decode control circuit according to the present invention;

FIG. 5 is a schematic diagram of an analog voltage input circuit of the present invention;

FIG. 6 is a schematic diagram of an analog switch circuit of the present invention;

FIG. 7 is a schematic diagram of an AD574 circuit to be tested;

Fig. 8 is a flow chart of the present invention.

Detailed Description

In order that the manner in which the invention is attained, as well as the features and advantages thereof, will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings.

As shown in FIG. 1, a test device for analog-to-digital conversion AD574 based on a single chip microcomputer comprises an industrial personal computer, the single chip microcomputer, a decoding control circuit, an analog voltage input circuit, an analog switch circuit and the AD574 to be tested.

As shown in fig. 7, which is a schematic circuit diagram of an AD574 to be tested, the AD574 to be tested uses a base which is convenient to plug on a hardware circuit, and effective electrical connection can be ensured only by installing the AD574 to be tested on a test socket without repeated disassembly in the test process, the AD574 to be tested is controlled by the control output of the decoding control circuit, the output voltage of the analog switch circuit is subjected to analog-to-digital conversion, and the analog-to-digital conversion result is transmitted to the singlechip for processing through a data line.

The industrial personal computer adopts an upper computer test program as a man-machine interaction tool, is connected with the singlechip through an RS232 serial port and is used for setting a test state and displaying a test result.

The industrial personal computer comprises analog-digital conversion time sequence control function software, serial port interrupt function software and serial port transmission function software.

The analog-to-digital conversion time sequence control function software is used for converting the analog voltage of the channel n into digital quantity and storing the conversion result into variables ADHI and ADL0.

The serial port interrupt function software and the serial port sending function software are used for receiving commands sent by the upper computer and sending analog-to-digital conversion results to the upper computer.

The singlechip is used as a processor and is used for running programs, processing information and controlling each module to work cooperatively. The circuit of the singlechip is shown in fig. 2 and 3, and consists of the singlechip, a MAX708 watchdog chip and a MAX232 serial port protocol chip. Wherein AD 0-AD 7 are multiplexed address lines and data lines, and are connected with the decoding control circuit, the analog switch control circuit and the address lines and data lines of AD574 to be tested; control pin 21 (STS), control pin 22 (CS 1), and control pin 23 (LE) are included for controlling the cooperation of the other circuits. The control pin 21 (STS) is connected to pin 28 on the AD574 to be tested, the control pin 22 (CS 1) is connected to pin 3 on the AD574 to be tested, and the control pin 23 (LE) is connected to the decoding control circuit.

The decoding control circuit is connected with the singlechip, and is used for decoding the address line, the data line and the control output which are output by the singlechip, and controlling the AD574 to be detected by the decoded control output. As shown in fig. 4, the decoding control circuit is composed of a latch 74HC373 chip, and latches control signals of two control pins A0 and RC. The latch 74HC373 chip includes pin 19 (AO) connected to pin 4 on the AD574 to be tested, and pin 18 (RC) connected to pin 5 on the AD574 to be tested.

The analog voltage input circuit is used for respectively conditioning eight paths of analog voltages so as to meet the requirement of test voltages. The analog voltage input circuit is composed of a DG508 chip, as shown in fig. 5, and the DG508 chip includes a pin 1, a pin 15, and a pin 16 connected to an analog switch circuit.

The analog switch circuit is controlled by the decoding control circuit, is connected with the analog voltage input circuit and the AD574 to be tested, and is used for selecting one path of analog voltage from eight paths of analog voltages as the voltage to be tested, and as shown in fig. 6, the analog switch circuit comprises a pin 2 connected with a pin 1 on the analog voltage input circuit, a pin 10 connected with a pin 15 on the analog voltage input circuit, and a pin 7 connected with a pin 16 on the analog voltage input circuit.

(6) The AD574 to be tested starts 12-bit data conversion;

The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A test device of AD574 based on singlechip's AD conversion, characterized in that: comprising the following steps:

2. The test device for analog-to-digital conversion AD574 based on the single chip microcomputer according to claim 1, wherein: the industrial personal computer comprises analog-digital conversion time sequence control function software, serial port interrupt function software and serial port transmission function software.

3. The test device for analog-to-digital conversion AD574 based on the single chip microcomputer according to claim 1, wherein: the singlechip comprises a singlechip, a MAX708 watchdog chip and a MAX232 serial port protocol chip.

4. The test device for analog-to-digital conversion AD574 based on the single chip microcomputer as set forth in claim 3, wherein: the singlechip comprises an address line and a data line which are multiplexed by AD 0-AD 7 and are connected with the decoding control circuit, the analog switch control circuit and the address line and the data line of the AD574 to be detected, a control pin 21 connected with a pin 28 on the AD574 to be detected, a control pin 22 connected with a pin 3 on the AD574 to be detected, and a control pin 23 connected with the decoding control circuit.

5. The test device for analog-to-digital conversion AD574 based on the single chip microcomputer as set forth in claim 4, wherein: the decoding control circuit is composed of a latch 74HC373 chip and latches control signals of two control pins A0 and RC.

6. The test device for analog-to-digital conversion AD574 based on single chip microcomputer as set forth in claim 5, wherein: the latch 74HC373 chip includes pin 11 connected to control pin 23, pin 19 connected to pin 4 on the AD574 to be tested, and pin 18 connected to pin 5 on the AD574 to be tested.

7. The test device for analog-to-digital conversion AD574 based on the single chip microcomputer according to claim 1, wherein: the analog voltage input circuit is composed of a DG508 chip, and the DG508 chip comprises a pin 1, a pin 15 and a pin 16 which are connected with the analog switch circuit.

8. The test device for analog-to-digital conversion AD574 based on the single chip microcomputer as claimed in claim 7, wherein: the analog switch circuit comprises a pin 2 connected with a pin 1 on the analog voltage input circuit, a pin 10 connected with a pin 15 on the analog voltage input circuit, and a pin 7 connected with a pin 16 on the analog voltage input circuit.

9. A test method of analog-to-digital conversion AD574 based on a single chip microcomputer is characterized by comprising the following steps: a test device for applying the single-chip microcomputer-based analog-to-digital conversion AD574 according to any one of claims 1 to 8, comprising the steps of:

(6) The AD574 to be tested starts 12-bit data conversion;