basic addition review basic adders and the carry problem carry propagation speedup speed/cost...
Post on 04-Jan-2016
216 Views
Preview:
TRANSCRIPT
Basic Addition
• Review Basic Adders and the Carry Problem
• Carry Propagation Speedup
• Speed/Cost Tradeoffs
• Two-operand Versus Multi-operand Adders
Half Adders
Adder Equations
Full Adder
F (A,B,C) = A B C G = AB + AC + BC
A B
S
CiCoCin
A B
Cout
Sum
Sum = A B Cin
Cout = AB + Cin A + Cin B = AB + Cin (A + B)
Full Adder (FA)
4-Bit Ripple Carry Adder
A B
S
CiCo
A B
S
CiCo
A B
S
CiCo
A B
S
CiCo Cin
A(0)
Cout
B(0)A(1) B(1)A(2) B(2)A(3) B(3)
C(0)C(1)C(2)C(3)C(4)
Sum(0)Sum(1)Sum(2)Sum(3)
A[3:0] B[3:0]
SUM[3:0]
+ C[0]C[4]
Full Adder Implementations
Ripple Carry Adder Layout
28T Full Adder Implementation
4-Bit AdderReduced Ripple Delay
24T Full Adder Implementations
Adder Circuits Using FA
Delay in Ripple Adder
Adders as Logic Elements
Adder Exceptions
Adder Exception Circuitry
Carry Propagation Analysis
Carry Propagation Analysis
Carry Completion Detection
Counters
Asynchronous up-Counter
Three-stage up-Counter
Generate, Propagate and Kill
Transfer Signal
Manchester Carry Chain
top related