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מבנה המחשב + מבוא למחשבים ספרתיים תרגול 10#. Flip-Flops. An edge-triggered flip-flop is not a combinational circuit. Claim: An edge-triggered flip-flop is not a combinational circuit. Proof: Every combinational circuit implements a Boolean function.
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מבנה המחשב + מבוא למחשבים ספרתייםתרגול 10# Flip-Flops
An edge-triggered flip-flop is not a combinational circuit. Claim: An edge-triggered flip-flop is not a combinational circuit. Proof: Every combinational circuit implements a Boolean function. We show that an edge-triggered flip-flop is not an implementation of any Boolean function. Assume the an edge-triggered flip-flop FF implements a Boolean function f with propagation delay tpd(f) .
1 0 For CLK = 0 and D = 0, f(0,0) = Q = 1. For CLK = 0 and D = 0, f(0,0) = Q = 0. ⇒ FF doesn’t implement any Boolean function. ⇒ FF is not a combinational circuit.
FF’ Overcoming non-empty intersection of Ci and Ai
PD(MUX) CONT(MUX) Clock enabled edge-triggered flip-flop
An edge-triggered flip-flop with a reset signal Definition: An edge-triggered flip-flop with a reset signal is defined as follows:
Changing the flip-flop parameters (0) A concatenation of iG gates: • Goal: • (1) Design an edge-triggered flip-flop FF’ with thold(FF) ≤ 0. • (2) Design an edge-triggered flip-flop FF’’ with tsu(FF) ≤ 0.
FF’ Changing the flip-flop parameters (1)
X FF’’ Changing the flip-flop parameters (2) PD(Gi) PD(Gi) CONT(Gi) CONT(Gi)