7. Controlled Buffer/Inverter Synthesis

An XNOR gate is an equivalence detector. It outputs 1 only when its two inputs are at the same logic level.

Output Equation:

Data Out = Data In XNOR (Config XNOR 0)

Calculation Breakdown:

1. Inversion of Config: Since the XNOR gate outputs 0 when inputs are different (e.g., Config=1, Input=0) and 1 when they are the same (Config=0, Input=0), tying one input to 0 forces the gate to act as an inverter. Thus, Config XNOR 0 effectively performs the function of NOT Config.
2. Logic Operation: When we feed the Data In signal into the second XNOR gate along with the inverted Config signal:
   • When Config = 0: The Inverter Block outputs 1. The second XNOR gate performs Data In XNOR 1. According to the XNOR truth table, this results in the Data In signal (Buffer).
   • When Config = 1: The Inverter Block outputs 0. The second XNOR gate performs Data In XNOR 0. According to the truth table, this results in the inverted Data In signal (Inverter).

Circuit Implementation:

• Inverter Block: Connect one input of the first XNOR gate to logic 0 (ground) and the other input to the Config rail.
• Logic Block: Connect the Data In signal and the output of the first XNOR gate to the inputs of the second XNOR gate.
• Connect: Map the output of the second XNOR gate to the Data Out probe.