Circuit code was designed by BASCOM language, this program was implemented on AVR microcontroller, and then amplifier circuit was examined. At the end of ...
Automatic Testing For Electronic Circuit Using Microcontroller
R.A. Adam1, H.H. Abuellhassan2, A.A. Mohammed3, A.A. Elbadawi4 1-4
Department of Physics, Faculty of Science and Technology, Alneelain University, Khartoum 11121 Sudan
Abstract The focus of this paper revolves around the application of the concept of Self-Testing, which facilitates the maintenance of electronic circuits and makes the system available to take advantage of its potential to facilitate the user diagnosing maintenance. Where the previous system was manually; here lies the difficulty of diagnosing faults for the user. The adoption of the system entirely on human element leads the errors and wasted time. The importance of this research is arriving to Self System, which serves the user, and eases of delete operation, addition and modulates with accuracy in work. Circuit code was designed by BASCOM language, this program was implemented on AVR microcontroller, and then amplifier circuit was examined. At the end of this paper the possibility of diagnosing faults in electronic circuits were well treated, and the goal has been reached; which provided the user time, effort and the cost of maintenance process was reduced.
Key words: Microcontroller, Self-testing, BASCOM language.
Introduction Incident or asymmetric error codes have extensively been studied, not only from theoretical interest but from application to computer systems or communication systems. Recently, attention has been focused on the detecting[1]. Efficient procedures for estimating fault detection capabilities of self-testing circuits designed using the circular self-test path technique are presented. Success in the competitive global markets of integrated circuits and electronics systems requires the design and fabrication of increasingly complex products coupled with ever-increasing quality requirements and ever-decreasing market windows of opportunity. Now a day, the integrated circuit testing was considered to add some value to a product and thus, the testing responsibilities could simply be passed on, from designers to engineers, leaving all testing considerations for the bad-end of the design or manufacturing process. Testing costs are often reported as representing anywhere from 10% to 50% or more of total product development costs[2]. Periodic testing of electronic devices on the field during application execution is becoming increasingly important. In addition, some of these applications are embedded and real-time, requiring the system to be operational for extended periods[3]. In such applications, field test must be cleverly interleaved with normal operation, such that the latter is not impacted, while at the same time guaranteeing the correct operation of the device, and identification of any malfunction or defects within a reasonable time. Software testing has been a hard nut in the testing area for its complex and time-consuming nature. Taking advantage of mature technologies in hardware testing, we proposed a new approach to developing a new dimension of software testing called build-in-self-test (BIST) for software, which has long been applied in hardware testing as well as design for testability[4]. This idea of testing methods from hardware is just to alleviate the burden of testing for software by transferring some testing work onto the programmer during programming so that the programmer and the tester can work together. In order to increase the number of test points, while still keeping low pin overhead, a built-in self-test (BIST) structure has been proposed for analog circuit fault diagnosis and it proposed to detect non-traditional faults. A built-in self-test (BIST) or built-in test (BIT) is a mechanism that permits a machine to test itself and allows access to some internal nodes so that the fault diagnosis process can be significantly simplified[5].
This correspondence demonstrates a new kind of error-checking scheme for multioutput combinational circuits and its use for a built-in testing method. Using this self-testing checker, a self-verification testing method, which takes advantage of the automatic fault-detection capability of a checker, is shown to be applicable to testing combinational circuits[6]. Many circuits tested dynamically, but sometimes we cannot see most of the control signals, data transfer, etc; which allow the system to operate. Also sometimes it impossible to examine directly the component, to simplify this automatic test was used. Automatic or Automated Test Equipment (ATE) is any apparatus that performs tests on a device, known as the Device Under Test (DUT) or Unit Under Test (UUT), using automation to quickly perform measurements and evaluate the test results. An ATE can be a simple computer, controlled digital, multimeter or a complicated system containing dozens of complex test instruments (real or simulated electronic test equipment) capable of automatically testing and diagnosing faults in sophisticated electronic packaged parts or on Wafer testing, including System-On-Chips and Integrated circuits. ATE is widely used in the electronic manufacturing industry to test electronic components and systems after being fabricated. Periodic testing of microprocessors is a viable low-cost alternative for a wide variety of embedded systems which cannot afford hardware or software redundancy techniques but can necessitate the detection of intermittent or permanent faults. Built -in self-test (BIST) can reduce the cost into two ways: Reduces test-cycle duration and Reduces the complexity of the test setup, by reducing the number of input and output signals that must be examined under tester control[7]. The aim of this research is to convert the manual traditional system for verifying faults to the automatic detection system[8]. This system provides services to users for being able to arriving to the specific fault in any time and also to avoid developing and buying more sophisticated and very expensive testers and to increase the testability of the self-testing algorithm which is used to allocate the defective components of a given analogue circuit. The maintenance of the devices and faults diagnosis manually may take a lot of time. Also the expert may forget or fall into big mistakes which may impede operation of the device completely. Combine a software tool running on a personal computer with a hardware development board based on a microcontroller for automatic testing.
The main objective of the study is development of testing system to overcome problems of wasting time and effort by designing smart software supported by champion hardware[9].
Methodology After building an electronic circuit which will be tested, it must be analysis by using bias points. Then the hardware should be equipped with suitable software and implement it on a microcontroller. When faced with having to troubleshoot a circuit, the first thing need is a schematic with the proper dc and signal voltages labeled. This schematic with voltages indicated at certain points. The schematic that was examined the (two-stage amplifier) Figure 1.
Figure 1: Two Stage Amplifier
In the error-checking logic employed, the output from the circuits being checked is partitioned into several groups. The predicted group parity is compared to that produced from the output in each group. This checking circuit can be implemented systematically.
The self-testing is implemented for some multioutput combinational circuits. The schematic for the two-stage amplifier was analyzed by biasing points and it has been found the correct voltages at each test point (TP).
Results and Discussion Four important test points were chosen in this work; (TP1=1.58V), (TP2=5.70V), (TP3=1.58V) and (TP4=5.70V).
Figure 2 Two Stage Amplifier with test points
Obviously TP1 was equal TP3 and TP2 was equal TP4, so that TP1 and TP2 were examined as example. According to circuit analysis TP1 could be between 0.7V and 2.5V, so any other value was not acceptable. On the other hand TP3 could be between 0V and 10V, so any other value was not acceptable. The concept of this ranges was accomplished by comparators, each TP has two comparators; one for the upper value and one for the lower value; which was the input of the microcontroller.
The AVR microcontroller was programmed using BASCOM language. The BASCOM language is practical and easy, so this allows to programming many options. Here the program about selftesting. The Self-Testing Code is: $regfile = "m32def.dat" $crystal = 8000000 ConfigLcdpin = Pin , Db4 = Portc.4 , Db5 = Portc.5 , Db6 = Portc.6 , Db7 = Portc.7 , E = Portd.3 , Rs = Portd.4 ConfigLcd = 20 * 4 Config Pina.0 = Input Config Pina.5 = Input Sw1 Alias Pina.0 Sw2 Alias Pina.5 Dim Sw1 As Bit Dim Sw2 As Bit Do Gosub Check_p1 Gosub Check_p2 Loop End
'end program
Check_p1: CLS If Sw1 = 1 Then Lcd "TP1 is not ok" Else Lcd "TP1 is ok"
Waitms 500 Return Check_p2: Cls If Sw2 = 1 Then Lcd "TP2 is not ok" Else Lcd "TP2 is ok" Waitms 500 Return The work which was discussed during this research was activated and produced a useful result. It saves time and cost, it makes possible for adding or deleting information. This work improves the method of diagnosis faults, easing the system use and it also diagnosing faults very well. The designed system achieved its objectives correctly. It is secured and depends on high technology.
Conclusion: In this work, a built-in self-testing (BIST) method was proposed to detect non-traditional faults. Many systems are too complex to be able to visualize all of the system details; so the BIST is a wonderful solution.
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