Combinational versus sequential logic
Combinational means memoryless
- Outputs depend only on the present inputs
- Apply fixed inputs A, B
- Wait for clock edge
- Observe C
- Wait for another clock edge
- Observe C again: C will stay the same
Sequential systems have memory
- Outputs depend on the present inputs and on the previous inputs
- Apply fixed inputs A, B
- Wait for clock edge
- Observe C
- Wait for another clock edge
- Observe C again: C may be different