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Codiode/Problems/Sequential Logic

Negative Edge-Triggered DFF: CLK Polarity Swap

EasyLogic CircuitBuild

High-speed double data rate (DDR) interfaces and specialized clock dividers require capturing data on both phases of a clock signal. The negative edge-triggered flip-flop samples its input when the clock transitions from high to low.

Implement a master-slave D flip-flop that captures input D on the falling edge of CLK.

| CLK transition | D | Q_next | |------------------|-----|----------| | Rising (0 to 1) | X | Q | | Falling (1 to 0) | 0 | 0 | | Falling (1 to 0) | 1 | 1 | | Static | X | Q |

Constraints

  • Implement using a master-slave latch topology.
  • Ensure the master latch is transparent when CLK is high.
  • Ensure the slave latch is transparent when CLK is low.

Topics

sequentialdfflatchesnegative-edge

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