Control Unit Design

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Arjit Sharma
01 Min

The Control Unit (CU) is the CPU’s command center, directing all operations by decoding instructions and coordinating the ALU, registers, and memory.

Role of the Control Unit

The CU manages the execution of each instruction by -

  • Generating control signals to activate components.
  • Directing data flow between registers, ALU, and memory.
  • Synchronizing operations with the CPU’s clock.
  • Updating the Program Counter to fetch the next instruction.

Types of Control Units

1. Hardwired Control Unit

Built using fixed logic circuits (combinational logic + timing signals). It is fast and efficient, but inflexible as changing behavior requires redesigning hardware.

2. Microprogrammed Control Unit

Stores micro-instruction in control memory(ROM). It is slightly slower but easier to extend, used in complex CPUs like the Intel 8086.

Conclusion

The Control Unit directs all CPU operations, transforming binary instruction to precise actions.

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