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Welcome ToOur presentationPresented by
Shahriar Reza Rusel
ID-011132065Samrin Ahmed Riya
ID-011142021Rayhan Ahamed
ID-011142141Rakib Hasan Suvo
ID-011142016Dept-CSE
A digital circuit. Sums the amplitudes of two input signals.
Representation of Adders: Binary-Coded-Decimal or Excess-3
Processor Use: Calculate addresses, table indices and similar operations.
What is ADDER ?
Types of Adder
Half ADDER: A computational device. Adds two binary digits . No carry as input. Produces a sum bit and
a carry bit.
Types of Adder
INPUTS OUTPUTSA B SUM CARRY0 0 0 00 1 1 01 0 1 01 1 0 1
Half Adder Circuit
Full Adder: A computational device. Adds three one-bit binary numbers. Produces a sum of two inputs and a carry value.
Types of ADDER (Cont...)
INPUTS OUTPUTSA B CIN COUT S0 0 0 0 00 0 1 0 10 1 0 0 10 1 1 1 01 0 0 0 11 0 1 1 01 1 0 1 01 1 1 1 1
Full Adder Circuit
Also Known as 8421 digit. A 4-bit binary adder. Adds two 4-bit digits having a BCD. Resulting format 4-bit output digit. Sum exceeding decimal value of 9, a carry’s generated.
What is BCD ADDER?
Conversion and Coding
(12)10
1100 00010010Conversion Coding(using BCD code for each digit)
A 4-bit BCD code’s used to represent 0 to 9 digits. Adding BCD numbers using BCD addition. Adding 6 with the sum while exceeding 9 and generating a carry. By adding 6 to the sum, make an invalid digit valid.
.
Maximum sum is 9+9 + 1 = 19
Max digit Carry from previous digits
Number C S3 S2 S1 S00 0 0 0 0 01 0 0 0 0 12 0 0 0 1 03 0 0 0 1 14 0 0 1 0 05 0 0 1 0 16 0 0 1 1 07 0 0 1 1 18 0 1 0 0 09 0 1 0 0 1
Number C S3 S2 S1 S010 1 0 0 0 011 1 0 0 0 112 1 0 0 1 013 1 0 0 1 114 1 0 1 0 015 1 0 1 0 116 1 0 1 1 017 1 0 1 1 118 1 1 0 0 019 1 1 0 0 1
BCD adder sum Binary sum
Number C S3 S2 S1 S0
10 1 0 0 0 011 1 0 0 0 112 1 0 0 1 013 1 0 0 1 114 1 0 1 0 015 1 0 1 0 116 1 0 1 1 017 1 0 1 1 118 1 1 0 0 019 1 1 0 0 1
K s3 s2 s1 s00 1 0 1 00 1 0 1 10 1 1 0 00 1 1 0 10 1 1 1 00 1 1 1 11 0 0 0 01 0 0 0 11 0 0 1 01 0 0 1 1
+6
If sum is up to 9 Use the regular Adder.
If the sum > 9 Use the regular adder and add 6 to the
result
Sum of two BCD digits exceeding 9. A carry is generated. Converting the invalid digit into valid digit. Carry generated by adding 6 to the invalid
BCD digit’s passed on to the next BCD digit.
Binary sum
Number K S3 S2 S1 S010 0 1 0 1 011 0 1 0 1 112 0 1 1 0 013 0 1 1 0 114 0 1 1 1 015 0 1 1 1 116 1 0 0 0 017 1 0 0 0 118 1 0 0 1 019 1 0 0 1 1
C = K +
Binary sum
Number K S3 S2 S1 S010 0 1 0 1 011 0 1 0 1 112 0 1 1 0 013 0 1 1 0 114 0 1 1 1 015 0 1 1 1 116 1 0 0 0 017 1 0 0 0 118 1 0 0 1 019 1 0 0 1 1
C = K + S3*S2+
Binary sum
Number K S3 S2 S1 S010 0 1 0 1 011 0 1 0 1 112 0 1 1 0 013 0 1 1 0 114 0 1 1 1 015 0 1 1 1 116 1 0 0 0 017 1 0 0 0 118 1 0 0 1 019 1 0 0 1 1
C = K + S3*S2+ S3*S1
4-bit Adder
4-bit Adder
0 0 s3 s2 s1 s0
S3 S2 S1 S0
Cin
K
0 1 1 00 1 1 1
1 1 0 1
0
1 1 0 1 1 1
1
0 0 1 1
1
0
1
Applications in Decimal Number Display. Systematic running of counters. Organized digital clocks.
http://www.electronics-tutorials.ws/combination/comb_7.html
http://www.encyclopedia.com/doc/1O11-binarycodeddecimal.html
http://www2.elo.utfsm.cl/~lsb/elo211/aplicaciones/katz/chapter5/chapter05.doc4.html
https://tams-www.informatik.uni-hamburg.de/applets/hades/webdemos/20-arithmetic/10-adders/bcd-adder.html
