comparators & code converter ppt
DESCRIPTION
Comparators & Code Converter PptTRANSCRIPT
Alpha Breathing
Evocation
2
Code Converters
3
4
BCD-to-Excess-3 Code Converter - Specificaiton
The excess-3 code for a decimal digit is the binary combination correspondingto the decimal digit plus 3. For example, the excess-3 code for decimal digit 5is the binary combination for 5 + 3 = 8, which is 1000.
Each BCD digit is four bits with the bits, from most significant to leastsignificant, labeled A, B, C, D. Each excess-3 digit is four bits, with the bits,from most significant to least significant, labeled W, X, Y, Z.
ABCD
WXYZ
BCDdigit
Excess-3digit
BCD-toExcess-3
5
BCD-to-Excess-3 Code Converter - Formulation
6
BCD-to-Excess-3 Code Converter - Optimization
7
BCD-to-Excess-3 Code Converter - Optimization
8
BCD-to-Seven-Segment Decoder - Specification
Digital readouts found in many consumer electronic products often use LightEmitting Diodes (LEDs). Each digit of the readout is formed from seven LEDsegments. Each segment can be illuminated by a digital signal. A BCD-to-
seven-segment decoder is a combinational circuit that accepts a decimal digit inBCD and generates the appropriate outputs for the segments of the displayfor the decimal digit. The seven outputs of the decoder (a,b,c,d,e,f,g)select the corresponding segments in the display. BCD-to-seven-segmentdecoder has four inputs, A, B, C, and D for the BCD digit and seven outputs,a through g, for controlling the segments.
9
BCD-to-Seven-Segment Decoder - Formulation
10
BCD-to-Seven-Segment Decoder - Optimization
a= A’C + A’BD + B’C’D’ + AB’C’
b= A’B’ + A’C’D’ + A’CD + AB’C’
c= A’B + A’D + B’C’D’ + AB’C’
d= A’C^D’ + A’B’C + B’C’D’ + AB’C’ + A’BC’D
e= A’CD’ + B’C’D’
f= A’BC’ + A’C’D’ + A’BD’ + AB’C’
g= A’CD’ + A’B’C + A’BC’ + AB’C’
FOUR BIT BINARY TO GRAY CODE CONVERTER –DESIGN
11
INPUT ( BINARY) OUTPUTS (GRAY CODE)
B3 B2 B1 B0 G3 G2 G1 G0
0 0 0 0 0 0 0 0
0 0 0 1 0 0 0 1
0 0 1 0 0 0 1 1
0 0 1 1 0 0 1 0
0 1 0 0 0 1 1 0
0 1 0 1 0 1 1 1
0 1 1 0 0 1 0 1
0 1 1 1 0 1 0 0
1 0 0 0 1 1 0 0
1 0 0 1 1 1 0 1
1 0 1 0 1 1 1 1
1 0 1 1 1 1 1 0
1 1 0 0 1 0 1 0
1 1 0 1 1 0 1 1
1 1 1 0 1 0 0 1
1 1 1 1 1 0 0 0
MSB0
+1
+1
+0
+1
0 1 0 1 1
Binary code
Gray code
Simplification using K-maps
12
Logic Diagram
13
FOUR BIT GRAY CODE TO BINARY CONVERTER –DESIGN
14
INPUT ( GRAY CODE) OUTPUTS (BINARY )
G3 G2 G1 G0 B3 B2 B1 B0
0 0 0 0 0 0 0 0
0 0 0 1 0 0 0 1
0 0 1 0 0 0 1 1
0 0 1 1 0 0 1 0
0 1 0 0 0 1 1 1
0 1 0 1 0 1 1 0
0 1 1 0 0 1 0 0
0 1 1 1 0 1 0 1
1 0 0 0 1 1 1 1
1 0 0 1 1 1 1 0
1 0 1 0 1 1 0 0
1 0 1 1 1 1 0 1
1 1 0 0 1 0 0 0
1 1 0 1 1 0 0 1
1 1 1 0 1 0 1 1
1 1 1 1 1 0 1 0
MSB1
+0
+1
+0
+0
1 1 0 0 0
Gray code
Binary code
Puzzles
15
16
19
MIND MAP
20
Summary
Code Converters
Truth tableK-MapExcitation EquationLogic Diagram
22