c a n w e im p le m e n t e 1 a n d e 2 diferent

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Unformatted text preview: to J o e lle P in e a u ! ) C a n w e im p le m e n t E 1 a n d E 2 ? • Diferent speed and size!! P ro b le m : – E1 needs a 3-input OR gate. – E2 needs a 3-input AND gate. • S o lu tio n : M a k e it b y g r o u p in g g a te s A B • OR C OR Output A B C = OR Output A n d s im ila r ly fo r A N D g a te s . C O M P - 1 0 2 : C o m p u te r s a n d C o m p u tin g 13 ( th a n k s to J o e lle P in e a u ! ) M o r e c o m p l i c a te d g a te s : N A N D • NAND = Not AND • T h is c o r r e s p o n d s to a n A N D g a te fo llo w e d b y a N O T g a te . – Output = NOT ( A AND B ) A B Output C O M P - 1 0 2 : C o m p u te r s a n d C o m p u tin g 14 ( th a n k s to J o e lle P in e a u ! ) Text M o r e c o m p l i c a te d g a te s : N O R • NOR = Not OR • T h is c o r r e s p o n d s to a n O R g a te fo llo w e d b y a N O T g a te . – Output = NOT ( A OR B ) A B Output C O M P - 1 0 2 : C o m p u te r s a n d C o m p u tin g 15 ( th a n k s to J o e lle P in e a u ! ) M o r e c o m p l i c a te d g a te s : E X - O R • E X -O R = E X c lu s iv e O R • T h is c o r r e s p o n d s to a n O R g a te , e x c e p t th a t th e o u tp u t is F A L S E w h e n b o th in p u ts a r e T R U E . A B Output C O M P - 1 0 2 : C o m p u te r s a n d C o m p u tin g 16 ( th a n k s to J o e lle P in e a u ! ) C o m b i n i n g l o g i c g a te s • Logic gates can be combined to produce complex logical expressions. E.g.: ACTIVITY = (V1 AND V2) OR (V1 AND V3) OR (V2 AND V3) V1 V2 V3 • AND OR OR Output AND AND Logic gates can also be combined to substitute for another type of gate. C O M P - 1 0 2 : C o m p u te r s a n d C o m p u tin g 17 ( th a n k s to J o e lle P in e a u ! ) E x a m p le A B A B OR NOT Output NOT AND Output NOT Is there a unique set of blocks to represent a given expression? No! (Hint: Just write out the truth table for each set of gates, and see whether they are the same.) C O M P - 1 0 2 : C o m p u te r s a n d C o m p u tin g 18 ( th a n k s to J o e lle P in e a u...
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