A priority encoder is a digital circuit that encodes the position of the highest-order active input (the highest priority) into a binary code. It is used in applications where multiple inputs need to be prioritized, such as interrupt handling in microprocessors.
For a 4-to-2 priority encoder, the inputs are D3, D2, D1, D0, and the outputs are Y1, Y0, with V (valid) indicating if any input is active.
Here Priority is in order D3 > D2 > D1 > D0
| D3 | D2 | D1 | D0 | V | Y1 | Y0 |
|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | - | - |
| 0 | 0 | 0 | 1 | 1 | 0 | 0 |
| 0 | 0 | 1 | 0 | 1 | 0 | 1 |
| 0 | 0 | 1 | 1 | 1 | 0 | 1 |
| 0 | 1 | 0 | 0 | 1 | 1 | 0 |
| 0 | 1 | 0 | 1 | 1 | 1 | 0 |
| 0 | 1 | 1 | 0 | 1 | 1 | 0 |
| 0 | 1 | 1 | 1 | 1 | 1 | 0 |
| 1 | 0 | 0 | 0 | 1 | 1 | 1 |
| 1 | 0 | 0 | 1 | 1 | 1 | 1 |
| 1 | 0 | 1 | 0 | 1 | 1 | 1 |
| 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| 1 | 1 | 0 | 0 | 1 | 1 | 1 |
| 1 | 1 | 0 | 1 | 1 | 1 | 1 |
| 1 | 1 | 1 | 0 | 1 | 1 | 1 |
| 1 | 1 | 1 | 1 | 1 | 1 | 1 |
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Here you can find the data flow modeling of a 4 to 2 encoder.
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8 to 3 encoder and its testbench in structral modeling using a 4 to 2 encoder.
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8 to 3 encoder and its testbench in Behavioural modeling.
