When a system defines a HIGH voltage as binary 0 and a LOW voltage as binary 1, what is this logic convention called?

Introduction:
Logic conventions determine how physical voltages map to logical values. Two common conventions are positive logic and negative logic, which invert the mapping relative to each other.

Given Data / Assumptions:

• HIGH voltage is assigned to binary 0.
• LOW voltage is assigned to binary 1.
• We are asked to name this convention.

Concept / Approach:
In positive logic, HIGH corresponds to 1 and LOW to 0. In negative logic, the mapping is reversed: HIGH corresponds to 0 and LOW corresponds to 1. Therefore, the described mapping is negative logic.

Step-by-Step Solution:

Verification / Alternative check:
Truth tables under negative logic can be transformed to positive logic by complementing signals and reinterpretation; functional behavior remains consistent when conventions are applied uniformly.

Why Other Options Are Wrong:

• Positive logic: Opposite mapping (HIGH = 1).
• Invalid logic: The convention is valid; it is a defined alternative.
• Assertion-level logic: Refers to active-high or active-low signaling semantics, not the global numeric mapping itself.

Common Pitfalls:
Assuming negative logic is “wrong.” It is legitimate and often used in active-low control signals (e.g., enable_n).

Final Answer:
negative logic