ITI 1100 Lecture Notes - Lecture 9: Binary Number, And Gate

• School: University of Ottawa
• Department: Information Technology
• Course: ITI 1100

Document Summary

Lecture 9 - gate level minimization (chapter 4 part 2) Three inputs, x, y, z, are decoded into eight outputs, d0 through d7. Each output di represents one of the minterms of the 3 input variables. Di = 1 when the binary number xyz = i. The output variables are mutually exclusive; exactly one output has the value 1 at any time, and the other seven are 0. We can use active-low decoders to implement arbitrary functions as a product of maxterms. For example, here is an implementation of the function f(x,y,z) = m(4,5,7), using an active-low decoder. The ground symbol connected to en represents logical 0, so this decoder is always enabled. We need an and gate for a product of sums. Building a 3-to-8 decoder with two 2-to-4 decoders. We can use enable inputs to string decoders together.