Combinational logic design case studies

19-Apr-99


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Table of Contents

Combinational logic design case studies

General design procedure for combinational logic

Calendar subsystem

Formalize the problem

Choose implementation target and perform mapping

BCD to 7-segment display controller

Formalize the problem

Implementation as minimized sum-of-products

Implementation as minimized S-o-P (cont'd)

PLA implementation

PAL implementation

Production line control

Sketch of problem

Formalize the problem

Logical function unit

Formalize the problem

Arithmetic circuits

Number systems

Sign and magnitude

1s complement

1s complement (cont'd)

2s complement

2s complement (cont’d)

2s complement addition and subtraction

Why can the carry-out be ignored?

Overflow in 2s complement addition/subtraction

Overflow conditions

Circuits for binary addition

Full adder implementations

Adder/subtractor

Ripple-carry adders

Ripple-carry adders (cont’d)

Carry-lookahead logic

Carry-lookahead logic (cont’d)

Carry-lookahead implementation

Carry-lookahead implementation (cont’d)

Carry-lookahead adder with cascaded carry-lookahead logic

Carry-select adder

Arithmetic logic unit design specification

Arithmetic logic unit design (cont’d)

Arithmetic logic unit design (cont’d)

Arithmetic logic unit design (cont’d)

Summary for examples of combinational logic

Author: Gaetano Borriello

Email: cse370-webmaster@cs.washington.edu

Home Page: http://www.cs.washington.edu/education/courses/cse370/99sp/