411 REFERENCE · Wikibooks
Microprocessor Design/Control Unit
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
The control unit reads the opcode and instruction bits from the machine code instruction, and creates a series of control codes to activate and operate the various components to perform the desired task.
Simple Control Unit
In its most simple form, a control unit can take the form of a lookup table. The machine word opcode is used as the index into the table, and the various control signals are output to the respective destinations.
Complex Control Unit
A more complex version of a control unit is implemented as a finite state machine (FSM). Multi-cycle, pipelined, and other advanced processor designs may require an FSM-based control unit.
Further reading
Electronics/Control Unit
Digital Circuits/Finite State Machines
IB/Group 4/Computer Science/Computer Organisation