Review: MultiplexerAnnouncementsAgendaReview: MultiplexerSangkyum Kim (Sang)2/16/2007Announcements HW2 due extended by today (2/16) at 5pm. HW 3 is released Due at 5:00pm on 2/21/2007 (Wed) No late homework accepted Check your EWS account Non-engineering students taking Engineering classes are NOT given EWS accounts by defaultAgenda Multiplexer revisit Quiz Homework3 A 2n-to-1 multiplexer takes:nselect lines2ndata input lines makes:1outputMultiplexer - General We can actually implement a function with 3 variables with just one 22-to-1 mux, instead of an 23-to-1.n variables Æ 2n-1-to-1 multiplexerEfficient implementation How to use AND gates and OR gates to implement an 8-1 multiplexer. An NAND gates implementation of an 8-1 multiplexer.What’s inside? Can you use decoders and basic gates to make a multiplexer?Selector 1Selector 0Input 3Input 2Input 1Input 0OutputDecoderÆMultiplexerYou can write the expression for multiplexer(s) by truth tableTruth TableK-MapExpressionQuiz – Quiz 7: Question 2You can also find the expression for multiplexer(s) directly using boolean algebra.h = z’y’ + zxf = (z’)’y + z’h= zy + z’(z’y’ + zx) = zy + z’y’g = y’h’ + yx’= y’(z’y’ + zx)’ + yx’= y’(z+y)(z’+x’) + yx’= y’zx’ + yx’ = x’y + x’zQuiz – Quiz 7: Question 2 Use multiplexer in the efficient way without using invertors.What can you do to change the situation?Use other variables as the selectors.Quiz – Quiz 7: Question 3 The same question as before!Quiz – Quiz 7: Question
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