2014 Project Lead The Way Inc Digital Electronics Universal Gate NOR This presentation will demonstrate The basic function of the NOR gate How an NOR gate can be using to replace an ID: 448385
Download Presentation The PPT/PDF document "Universal Gate – NOR" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Universal Gate – NOR
©
2014 Project Lead The Way, Inc.
Digital ElectronicsSlide2
Universal Gate – NORThis presentation will demonstrate…The basic function of the NOR gate.How an NOR gate can be using to replace an AND gate, an OR gate or an INVERTER gate.How a logic circuit implemented with AOI logic gates could be re-implemented using only NOR gatesThat using a single gate type, in this case NOR, will reduce the number of integrated circuits (IC) required to implement a logic circuit.
AOI Logic
NOR Logic
More ICs = More $$
Less ICs = Less $$
2Slide3
NOR GateXYZ
0
0
1
0
1
0
1
0
0
1
1
0
X
Y
3Slide4
NOR Gate as an Inverter GateXZ0
1
1
0
X
(Before Bubble)
Equivalent to Inverter
4Slide5
NOR Gate as an OR GateXYZ
0
0
0
0
1
1
1
0
1
1
1
1
X
Y
NOR Gate
“Inverter”
Equivalent to OR Gate
5Slide6
NOR Gate as an AND GateXY
Z
0
0
0
0
1
0
1
0
0
1
1
1
Equivalent to AND Gate
X
Y
NOR Gate
“Inverters”
6Slide7
NOR Gate Equivalent of AOI Gates
INVERTER
OR
AND
7Slide8
Process for NOR ImplementationIf starting from a logic expression, implement the design with AOI logic.In the AOI implementation, identify and replace every AND,OR, and INVERTER gate with its NOR equivalent.Redraw the circuit.Identify and eliminate any double inversions. (i.e. back-to-back inverters)Redraw the final circuit.8Slide9
NOR ImplementationExample:Design a NOR Logic Circuit that is equivalent to the AOI circuit shown below.
9Slide10
NOR ImplementationSolution – Step 2
Identify and replace every AND,OR, and INVERTER gate with its NAND equivalent.
10Slide11
NOR ImplementationRedraw Circuit.
Solution – Step 3
11Slide12
NOR ImplementationIdentify and eliminate any double inversions.
Solution – Step 4
12Slide13
NOR ImplementationSolution – Step 5
Redraw Circuit.
13Slide14
Proof of Equivalence
14Slide15
AOI vs NORIC TypeGates
Gate / IC
# ICs
74LS04
1
6
1
74LS08
2
4
1
74LS32
1
4
1
Total
Number of ICs →
3
IC
Type
Gates
Gate / IC
# ICs
74LS02
7
4
2
Total
Number of ICs →
2
15