Flexible prototype board design for ADC/DAC control: Application to mini-projects

This paper describes a practical approach to the development of mini-design projects for junior and senior electrical engineering students. The mini-projects utilize the design of a prototype board for controlling an 8 or 12-bit analog-to-digital controller (ADC) and an 8 or 12- bit digital-to-analog controller (DAC). The work emphasizes the judicious use of the input/output (I/O) capabilities of an Intel-based personal computer (PC) for providing a very flexible and useful ADC/DAC controller circuit. The controller, which functions as an elementary data acquisition board, is built on an off-the-shelf prototype breadboard, which is installed on an EISA1 (Extended Industry Standard Architecture), 8MHz @ 8/16/32 bits data bus, 32 bit address, bus slot on the PC. The design allows for flexible use of the signals of the EISA bus for various design applications such as a simple digital proportional-integral-derivative (PID) control system and an ultrasonic ranger and RC Servo control circuit. The various design applications can constitute a series of mini-projects that can be tailored to several courses such as senior project, junior design etc... The ADC/DAC controller was used with a variety of application circuits at UDC. After a description of the controller board, the paper highlights the example of the design of a controller of an Ultrasonic Sonar Transducer and an RC Servo for range sensing application. The paper describes also the versatility of the design as well as its cost effectiveness. It illustrates the ease with which the design can allow students to use their computing skills as well as their hardware design skills. The paper also proposes the implementation of the controller design with a VHDL-based, complex programmable logic circuit (CPLD).