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Published byJoel Richards Modified over 9 years ago
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Digitale basistechniek lesplan DatumTheoriePrakticumThuis 7 januariCombinational LogicTutorial Quartus II Herhaling Tutorial 12 JanuariCombinational LogicHalfadderFulladder 14 JanuariFunctions of Combinational Logic 2 bit decoderBCDto7seg 19 JanuariFunctions of Combinational Logic 2-1 mux1-2 demux 21 JanuariFlip-Flops and related devices Gated d- latch(8.3) Example 8.12 26 JanuariCounters en Statemachines Frequency divider8.11) 28 JanuariCounters en Statemachines 4 bit synch counter, verkeerslicht 2 februariHerhalingVerkeerslicht 2 4 februariOefententamen 9 februariTentamen
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Bepaling van het eindcijfer Het eindcijfer wordt bepaald door: 1 Voldoende Praktikum. (O/V) Tentamencijfer.
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Introduction to Logic Gates Logical gates –Inverter –AND –OR –NAND –NOR –Exclusive OR (XOR) –Exclusive NOR (XNOR) Draw Logic Circuit Analysis of Logic Circuit
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Introduction to Logic Gates Universal gates NAND and NOR –NAND gate –NOR gate Execution using NAND gate Execution using NOR gate Positive & Negative Logic SOP Expression Execution POS Expression Execution Integrated Logic Circuit Family
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Logic Gates
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Inverter gate The use of inverter: complement
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Logic Gates AND gate
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Logic Gates OR gate
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Logic Gates NAND gate
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Logic Gates NOR gate
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Logic Gates Exclusive OR (XOR) gate
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Logic Gates Exclusive NOR (XNOR) gate
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Draw Logic Gates When Boolean expression is obtained, we can draw logic gates Example: –F1 = xyz’ (use three input AND gate)
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Draw Logic Gates
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Logic Circuit Analysis When logic circuit is given, we can analyze the circuit to obtain logical expression Example: –What is the Boolean expression for F4
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Logic Circuit Analysis What is the Boolean expression for F5
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Universal Gates: NAND & NOR Gate AND/OR/NOT is enough to build any Boolean function Even though, other gates is also used because: –Very useful (no choice) –Save transistor’s number –Self sufficient (can build any gate from it) NAND/NOR: save, self sufficient XOR: useful (e.g. execute parity bit)
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NAND Gate NAND gate is self sufficient (i.e.can build any gate from it) Can be used for building AND/OR/NOT gate Build NOT gate using NAND gate
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NAND Gate Build AND gate using NAND gates Build OR gate using NAND gates
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NOR Gate NOR gate is also self sufficient Can be used for building AND/OR/NOT gate Build NOT gate using NOR gate
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NOR Gate Build AND gate using NOR gates Build OR gate using NOR gates
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Build using NAND gate It is not impossible to build Boolean expression using NAND gates Steps –Obtain sum-of-product Boolean expression E.g: F3 = xy’ +x’z –Use DeMorgan theorem to get expression using two level NAND gate E.g: F3 = xy’ +x’z = (xy’+x’z)” = ((xy’)’.(x’z)’)’
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Build using NAND gate
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Build using NOR gate It is not impossible to build Boolean expression using NOR gates Steps –Obtain product-of-sum Boolean expression E.g: F6 = (x+y’).(x’+z) –Use DeMorgan theorem to get expression using two level NAND gate E.g: F3 = (x+y’).(x’+z) =((x+y’).(x’+z))’’ = ((x+y’)+(x’+z)’)’
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Build using NOR gate
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Positive & Negative Logic In logic gate, most of the time –H (High Voltage, 5V) = logic 1 –L (Low Voltage, 0V) = logic 0 This is called positive logic However, if it is inverted, it is negative logic –H (High Voltage, 5V) = logic 0 –L (Low Voltage, 0V) = logic 1 Depends, some similar gate need different Boolean function
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Positive & Negative Logic Signal which is set to logic 1 is said to be active and true Signal which is set to logic 0 is said to be not active and false The name of active high signal is always written in non-compliment form The name of active low signal is always written in non-compliment form
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Positive & Negative Logic
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Construction of SOP Expression Sum-of-product expression can be built using –Two level logic gate AND-OR –Two level logic gate AND-NOT Logic AND-OR gate
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Construction of SOP Expression NAND-NAND circuit (with transformation circuit) –Add two balls –Change OR with NAND with inverted input and ball on it’s compliment input
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Construction of POS Expression Product-of-sum expression can be built using –Two level logic gate AND-OR –Two level logic gate AND-NOT Logic AND-OR gate
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Construction of POS Expression NOR-NOR circuit (with transformation circuit) –Add two balls –Change AND with NOR with inverted input and ball on it’s compliment input ”:
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