BusMUX (Bus Multiplexer)
Inputs
| Pin | Type | Description |
|---|---|---|
| A | bus8 | First input bus |
| B | bus8 | Second input bus |
| Sel | bit | Selector: 0 → A, 1 → B |
Outputs
| Pin | Type | Description |
|---|---|---|
| Q | bus8 | Sel=0 → A, Sel=1 → B |
How It Works
BusMUX works like a regular multiplexer but switches entire bytes (8-bit buses) instead of single bits. The selector pin determines which 8-bit input is routed to the output.
- Sel = 0: Q = A (all 8 bits of A pass through unchanged)
- Sel = 1: Q = B (all 8 bits of B pass through unchanged)
Internally, this is equivalent to 8 parallel single-bit multiplexers sharing the same selector signal.
Usage
Key element of the processor datapath. Used in the ALU to select operands, and in registers to decide what value to store. Critical for Levels 13–16.