Full Adder

ucla | CS M51A | 2023-01-10T14:35


Table of Contents

Definitions


  • prime
    • when the incoming bit is 0, denote its variable with a prime
    • e.g. Xi’ denotes 0 bit while Xi denotes 1 bit

Big Ideas


Logic Gates

NOT Gate

  • inverter, ON only when input is bit 0
  
inout
01
10

Full Adder

  • sum of products

$Zi = X_i’Y_i’C_{in} + X_i’Y_iC_{in}’ + X_iY_i’C_{in}’ + X_iY_iC_{in}$

  • product of sums

$Z_i = (X_i+Y_i+C_{in})(X_i+Y_i’+C_{in}’)(X_i’+Y_i+C_{in}’)(X_i’+Y_i’+C_{in})$

  • singular addition unit with a carry forward capability and 2 parameters
  • can be placed in series to carry forward addition parameters and carry bits
  • truth table

  • equations can be written as:
    • $Zi=(Xi+Yi+Ci)…(Xi’+Yi’+Ci’)$

Resources


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**SUMMARY
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