The decoder in one table
A reminder from Module 2. The 2-to-4 decoder turns a 2-bit address on a and b into four one-hot outputs: exactly one is high for each address.
| a | b | y3 | y2 | y1 | y0 |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | 1 |
| 0 | 1 | 0 | 0 | 1 | 0 |
| 1 | 0 | 0 | 1 | 0 | 0 |
| 1 | 1 | 1 | 0 | 0 | 0 |
Each output is 1 for exactly one row, so each is its own assign.