CSC270 Homework 4 Solution 2012

--D. Thiebaut 14:46, 29 February 2012 (EST)

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<onlysmith>

Problem #1

No, it is not a flip-flop. It flips, but doesn't flop. When you block the NAND, you store a 1 in the flip-flop. When you block the NOR, you also store a 1. There's no way to store a 0. It's not a flip-flop.

Problem #2

• what happens at t0:
  • Just before t0, D1 is 0. So after t0, Q0 is going to be 0.
  • Just before t0, Q0 is 0. So after t0, Q1 is going to be 0.
  • Just before t0, Q1 is 0. So after t0, Q2 is going to be 0.
• What happens at t1:
  • Just before t1, D1 is 0. So after t0, Q0 is going to be 0.
  • Just before t1, Q0 is 0. So after t0, Q1 is going to be 0.
  • Just before t1, Q1 is 0. So after t0, Q2 is going to be 0.
• What happens at t2:
  • Just before t2, D1 is 1. So after t0, Q0 is going to be 1.
  • Just before t2, Q0 is 0. So after t0, Q1 is going to be 0.
  • Just before t2, Q1 is 0. So after t0, Q2 is going to be 0.