Compare implementations

• PLA:

  • No shared logic terms in this example
  • 10 decoded functions (10 AND gates)

• PAL:

  • Z requires 4 product terms
    • 16 decoded functions (16 AND gates)
    • 6 AND gates are unused

• This decoder is a poor candidate for PLAs/PALs

  • 10 of 16 possible inputs are decoded
  • No sharing of AND terms

• Better option? Yes — a ROM

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