DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING, THE UNIVERSITY OF NEW MEXICO ECE-238L: Computer Logic Design Fall 2013.

Transcription

1 N iput DPARTMNT OF LCTRICAL AND COMPUTR NGINRING, TH UNIVRSITY OF NW MXICO C-8L: Coputer Logi Deig Fll MULTIPLXRS (MUXS) Note - Chpter Thi logi iruit elet oe o iput igl orr the elete iput to the output lie. Boole equtio or MUX-to-, MUX-to-, MUX8-to-: = + = + + e g h = e + + g + h Norll, ultipleer h iput, oe output, eletor ith it. N- But, i ultipleer h iput, here i ot poer o, the uer o it o the eletor i give :. = log N Multipleer ith le A ele iput provie u ith etr level o otrol. I the ultipleer i ele, the iruit jut ork. I the ultipleer i ot ele, o iput i lloe ito the output, the ultipleer output eoe (i the output i tive-high) or (i the output i tive-lo). The ele iput e either tive-high or tive-lo: ACTIV HIGH NABL ACTIV LOW NABL X X X X Itrutor: Diel Llo

2 N iput DPARTMNT OF LCTRICAL AND COMPUTR NGINRING, TH UNIVRSITY OF NW MXICO C-8L: Coputer Logi Deig Fll Bu Multipleer Uull e t iput igl to oti ore th oe it. I the igure, eh iput igl oti it. Thi u ultipleer e uilt ultipleer, eh tkig re o ol oe it or ll the iput. I() - I() - I(N-) - N- - I() I() I() - I() - - I(N-) N- I(N-) - N- = log N We hve N iput thereore the eletor h it. Note tht the eletor i the e or ll the ultipleer. I() I() I(N-) N- = log N Logi Ciruit ith MUX Multipleer e ue to ipleet Boole Futio. The eletor e thought the iput vrile, the iput it re ie vlue tht re pe oto the output orig to the eletor. Thi ultipleor ith ie iput ipleet logi utio. The utiolit o thi iruit i iilr to tht o Look-Up Tle (LUT), hih i ROM-like iruit hoe vlue re otie reig the. FPGA ipleet Boole utio uig LUT. I the eple, -to- LUT i LUT ith iput, i.e., it oti ree. 8-to- MUX utio to e ipleete = = -to- Look-up Tle Itrutor: Diel Llo

3 DPARTMNT OF LCTRICAL AND COMPUTR NGINRING, TH UNIVRSITY OF NW MXICO C-8L: Coputer Logi Deig Fll DMULTIPLXRS A eultipleer peror the oppoite opertio o the ultipleer. DCODRS Geerll pekig, eoer re iruit tht tror the iput ito output olloig erti rule, provie tht the uer o output i greter th or equl to the uer o iput. Here, e iu tr eoer or hih peii iput/output rule eit. Thee eoer hve iput output. We ho eple o: -to- eoer, -to-8 eoer, -to- eoer ith ele. The output i tivte he the eil vlue o the iput i equl to. DCODR DCODR DCODR X X DCODR ith ele Logi Ciruit ith Deoer Deoer e ue to ipleet Boole utio. Note tht eh output i tull iter: utio to e ipleete Itrutor: Diel Llo

4 DPARTMNT OF LCTRICAL AND COMPUTR NGINRING, TH UNIVRSITY OF NW MXICO C-8L: Coputer Logi Deig Fll Ipleetig Deultipleor ith Deoer B utiliig the ele iput o eoer our iput igl, e eetivel ipleet eultipleor uig eoer: X X NCODRS Geerll pekig, eoer re iruit tht tror the iput ito output olloig erti rule, provie tht the uer o output i loer th the uer o iput. Here, e iu tr eoer or hih peii iput/output rule eit. Thee eoer hve iput output. The opertio i etl the oppoite i the e o the eoer: heever iput i tivte, the the ie pper t the output (i ir or). NCODR NCODR Priorit oer: Str eoer: e hek hether peii iput i tivte or the output to hve vlue. Wht hppe he ore th oe iput i tivte? A olutio i to rete etr output tht i tivte to iite th uepete oitio h ourre. Aother ore iteretig olutio i to rete priorit eoer, tht i i ore th oe iput i tivte, the e ol p ttetio to the iput it o the highet orer. For eple i, the e ol p ttetio to, i, e ol p ttetio to. Thi reult i the olloig truth tle or -to- priorit eoer: PRIORITY NCODR Wht hppe he o iput i tivte? Here e ru out o output it i to repreet thi e. Thu, e ilue etr output tht it i he o iput tivte, otherie. Itrutor: Diel Llo

5 DPARTMNT OF LCTRICAL AND COMPUTR NGINRING, TH UNIVRSITY OF NW MXICO C-8L: Coputer Logi Deig Fll PRACTIC XRCISS. Ipleet the olloig utio uig i) eoer ii) ultipleer:.. Uig ONLY -to- MUX, ipleet 8-to- MUX.. Ipleet 6-to- MUX uig i) ol NAND gte, ii) ol NOR gte.. Veri tht the olloig iruit e o out o ive -to- eoer ith ele repreet -to-6 eoer ith ele. Tip: Crete the truth tle Uig ol -to- MUX, ipleet the XOR XNOR gte. 6. Uig ol -to- MUX, ipleet the olloig utio. 7. Coplete the olloig tiig igr: DCODR P P P Uko P P P P PRIORITY NCODR P Itrutor: Diel Llo