Tags: #◇Computer Science #◇CSARCH1 #◇Computer Architecture #◇Combinational Circuits #◇Combinational Circuit - Tri state gates
Combinational Circuit - Tri-state gates
◇Overview
This sub-module discusses the concept of tri-state gates.
Objective: Learn the concept of tri-state gates.
◇Tri-state Gate
- A tri-state gate is a gate with 3 outputs: 0, 1, and high-impedance (z).
- High-impedance (z) means the output is an open circuit (i.e., the output is disconnected).
- A control input is used to determine the output, whether it is a normal output or high-impedance.
- A tri-state gate is usually a unary-input gate (i.e., a buffer or NOT gate).
◇Tri-state Buffer
A tri-state buffer is a buffer with 3 outputs: 0, 1, and high-impedance (z).
- For a buffer, the output normally follows the input.
- Positive Control: The output is normal if the control is 1; otherwise, the output is high-impedance.
- Negative Control: The output is normal if the control is 0; otherwise, the output is high-impedance.
◇Tri-state NOT Gate
A tri-state NOT gate is an inverter gate with 3 outputs: 0, 1, and high-impedance (z).
- For a NOT gate, the output is the complement of the input.
- Positive Control: The output is normal (complemented input) if the control is 1; otherwise, the output is high-impedance.
- Negative Control: The output is normal (complemented input) if the control is 0; otherwise, the output is high-impedance.
◇References & Navigation
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ACTIVE RECALL VERIFICATION
Select an answer to verify conceptual comprehension and reveal the technical rationale.
What are the three possible outputs of a tri-state gate?
What does high-impedance state mean in a tri-state gate?
For a tri-state buffer with positive control, when is the output high-impedance?
How does a negative control tri-state buffer behave when its control input is 0?
A tri-state NOT gate with positive control will output what when control is 1 and input is 0?