Computer workstation systems using MIPS processors are: SGI, MIPS The design was spread over six chips: an integer unit (with .. HARDWIRED CONTROL. It also controls the transmission between processor, memory and the various Difference between Hardwired Control and Microprogrammed Control. The control unit (CU) is a component of a computer’s central processing unit ( CPU) that directs . Hardwired control units are generally faster than microprogrammed designs. Their design uses a fixed architecture—it requires changes in the.

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By using this site, you agree to the Terms of Use and Privacy Policy. It is implemented by using programming approach. This page was last edited on 20 Decemberat The Control Unit can either be hardwired or microprogrammed.

This organization can be very complicated if we have to make the control unit large. On some processors, the Control Unit may be further broken down into additional units, such as an instruction unit or scheduling unit to handle scheduling, or a retirement unit to ans with results coming from the instruction processorr.

Views Read Edit View history. Therefore, it has minimum flexibility.

Design of Control Unit | Computer Architecture Tutorial | Studytonight

Archived from the original on Central processing unit Digital electronics. A sequence of micro operations is carried out by executing a program consisting of micro-instructions. If the instruction set is changed, processog wiring should also be changed.

It tells the computer’s memory, hardwjred and logic unit and input and output devices how to respond to the instructions that have been sent to the processor. As it is hardwired, the instruction set is constant and does not change.

Difference Between Hardwired and Microprogrammed Control Unit

The circuit uses a fixed architecture. This CU instruction decode process is then repeated when the Program Counter is incremented to the next stored program address and the new instruction enters the CU from that address, and so on till the programs end. Thus by only using a program of set instructions in memory, the CU will configure all the CPU’s data flows as needed to manipulate the data correctly between instructions.


Hardwired Control Unit is a unit that uses combinational logic units, featuring a finite number of gates that can generate specific results based on the instructions that were used to invoke those responses.

Control unit generates timing and control signals for the operations of the computer. To do modifications in a Hardwired Control Unit, the entire unit should be redesigned. Microprograms were organized as a sequence of microinstructions and stored in special control memory.

It is implemented with the help of gates, flip flops, decoders etc.

The speed of operations in Hardwired Control Unit is fast. Depending on the type of instruction entering the CU, the order and number of sequential steps produced by the CU could vary the selection and configuration of which parts of the CPU’s hardware are utilized to achieve the instruction’s objective mainly moving, storing, and modifying data within the CPU.

The processor or the CPU is the main component of the computer that handles most of the tasks. Hardwired Control Unit is implemented using various electronic components such as combinational logic units and gates. Branch prediction Memory dependence prediction. More precisely, the Control Unit CU is generally a sizable collection of complex digital circuitry interconnecting and directing the many execution units i.

It directs the flow of data between the CPU and the other devices.

Control unit

Microprogrammed Control Unit It is implemented by using programming approach. In additon to the above differences, the Hardwired Control Unit uses a small instruction set while theMicroprogrammed Control Unit uses a large instruction set.


Data dependency Structural Control False sharing.

These microinstructions refer to a control word that resides in control memory, containing control signals for execution of micro-operations. Moreover, it is difficult to perform instruction decoding in Hardwired Control Unit than in Microprogrammed Control Unit. She is passionate about sharing her knowldge in the areas of programming, data science, and computer systems.


Microprogrammed Control Unit has a sequence of microinstructions stored in control memory. It is used in CISC. Leave a Reply Cancel reply.

The main difference between Hardwired and Microprogrammed Control Unit is that a Hardwired Control Unit is a sequential circuit that generates control signals while a Microprogrammed Control Unit is a unit with microinstructions in the control memory to generate control signals. It consists of main two subsystems: It also instructs the ALU which operation has to be performed on data. Also, there is no control memory usage in Hardwired Control Unit but, on the other hand, Microprogrammed Control Unit uses control memory.

Before talking about Microprogrammed Control Unit, it is important to understand some terms. However, Hardwired Control Units desgin difficult to modify and implement. This architecture is preferred in reduced instruction set computers RISC as they use a simpler instruction set. It is used in RISC. It is implemented through flip-flops, gates, decoders etc.

The inputs to control unit are the instruction register, flags, timing signals etc.