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Abc's Of Processor Design: Introductory Computer Architecture Using The Lis 4

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1997 Annual Conference


Milwaukee, Wisconsin

Publication Date

June 15, 1997

Start Date

June 15, 1997

End Date

June 18, 1997



Page Count


Page Numbers

2.51.1 - 2.51.13

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Paper Authors

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Ravi Pendse

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Everett L. Johnson

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

Session 2520


Everett L. Johnson, Ravi Pendse ASEE/Wichita State University

ABSTRACT At Wichita State University a three course sequence in the Digital Design area is offered. First year students are encouraged to take the first course. By their third semester it is possible for a student to enroll in the third course in the sequence. The third course entitled, Introduction to Computer Architecture, introduces the student to the art of designing a processor from scratch. This paper presents the design process and the application of the knowledge obtained in the first two courses in the sequence. The CAD tools used will be discussed as part of the bottom-up design process. Each module of the processor is designed and then integrated into the system as a ASIC cell. CAD tools are used to carry out simulation to verify the design process. The end result is a processor that can run a simple program making use of the CAD simulation tools. Extensions of the original design as special projects are presented.

INTRODUCTION Sometimes it is difficult to see the forest for the trees. The same type of vision obstruction occurs if computer architecture design is presented using a complex instruction set as the design model. Basic design steps are overwhelmed by the necessity to know the instruction set and perform the book keeping required to keep track of all the control and timing signals. At Wichita State University we developed and began using the LIS-4 (4-bit limited instruction set) architecture 15 years ago for use in an Introduction to Computer Architecture course. In 1987 this architecture was presented in a book on digital design [1]. This course is the third in a sequence of 3 undergraduate digital design courses The last 4 years we have made use of a computer aided logic design program called B2LOGIC which allows the students to build, test, and program the computer [2]. In the following sections we give an overview of the LIS-4 and the design as required by the students.


Figure 1 shows the basic architecture of the LIS-4. The architecture is a two bus architecture. The two buses are the output bus (BO) and the input bus (BI). The registers and their functions

Pendse, R., & Johnson, E. L. (1997, June), Abc's Of Processor Design: Introductory Computer Architecture Using The Lis 4 Paper presented at 1997 Annual Conference, Milwaukee, Wisconsin.

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