Monitoring eight sources with minimal MCU lines — how many input lines are needed using an 8-to-3 priority encoder? Assume standard enable logic is handled separately; focus on the data lines into the microcontroller.

Introduction / Context:
Microcontrollers often have limited I/O. Encoders allow multiple sources to be represented as a smaller set of lines. An 8-to-3 priority encoder outputs a 3-bit code corresponding to the highest-priority active input, reducing the required MCU input pins.

Given Data / Assumptions:

• There are eight distinct sources to monitor.
• An 8-to-3 priority encoder is used.
• Enable, valid, or interrupt lines (if any) are outside the “data bits” count for this question.

Concept / Approach:
An 8-to-3 encoder maps 8 inputs to a 3-bit binary index (since 2^3 = 8). With priority, if multiple inputs assert simultaneously, the highest-priority one determines the output code. The MCU reads the 3-bit value to know which source is active, conserving pins.

Step-by-Step Solution:

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