Encoder (8-to-3)
Use DigiSim's 8-to-3 Priority Encoder to encode the highest-numbered active input as a three-bit value. Input 7 has the highest priority.
Overview
The 8-to-3 Priority Encoder reports the index of the highest-numbered HIGH input. I7 has the highest priority and I0 the lowest.
Encoding Table
| Highest HIGH input | C B A |
|---|---|
| none or I0 | 000 |
| I1, I2, I3 | 001, 010, 011 |
| I4, I5, I6, I7 | 100, 101, 110, 111 |
Multiple HIGH inputs are valid; the highest-numbered one wins. Because the component has no valid
output, no active input and I0 alone both produce 000. OR-reduce I0–I7 externally when that
distinction is required.
Released inputs sample as LOW. Driven unknowns are resolved per encoded bit from the possible binary completions.
Simulation Boundary
Priority, polarity, width, and absence of a valid output are fixed; no package-level electrical behavior is modeled.
Learning Path
Prerequisites
Next Steps
Frequently Asked Questions
How does 8-to-3 priority encoding work?
Eight inputs are encoded as binary 0–7, with input 7 highest priority. If inputs 3 and 7 are HIGH, the result is 111; if none is HIGH, the result is 000 because no valid output is provided.
How can I distinguish input 0 from no active input?
This component cannot distinguish those cases by itself because both produce 000. If that distinction matters, create an external valid signal by OR-reducing all eight inputs and evaluate it alongside the encoded output.