Which of the below given signals can be received as output signals from a hardwired control...
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Which of the below given signals can be received as output signals from a hardwired control unit?
I) ALU operation signals
II) Data-path signals
III) External Bus signals
Show answer & explanation
A hardwired control unit generates control signals that directly manage internal CPU operations. It outputs ALU operation signals (to specify which operation the ALU performs) and data-path signals (to route data between registers and the ALU). However, external bus signals are typically managed by separate bus interface logic or I/O control units, not the hardwired control unit itself. The control unit is internal to the CPU and does not directly interface with external buses.
Step-by-step Derivation:
Analyze the role of a hardwired control unit:
ALU Operation Signals (I): ✓ YES
- The control unit must output operation codes (like ADD, SUB, MUL) to tell the ALU what to do.
- This is a core responsibility of the control unit.
Data-path Signals (II): ✓ YES
- The control unit outputs control signals to multiplexers, buses, and registers within the data path.
- These signals determine data flow between CPU components (registers, ALU, memory interface).
External Bus Signals (III): ✗ NO
- The hardwired control unit is internal to the CPU.
- External bus communication (system bus, memory bus) is handled by bus interface units, memory controllers, or I/O controllers.
- The control unit may output signals to these external interface units, but does not directly generate external bus signals.
Conclusion: Only (I) and (II) are output signals from a hardwired control unit.