Answer to Explain the difference between hardwired control and microprogrammed control. Is it possible to have a hardwired. The main difference between Hardwired and Microprogrammed Control Unit is that a Hardwired Control Unit is a sequential circuit that. In this lesson, you will learn how microprogramming and hardwired control sets are designed in computer architecture. You will be able to describe.

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Microprogrammed Control Unit has a sequence of microinstructions stored in control memory. Most computer resources are managed by the CU. Hardwired microcode machines are free to use. Views Read Edit View history. The bases of this opinion are as follows: In Microprogrammed Control Unit, modifications can be implemented by changing the microinstructions in the control memory. Therefore, Microprogrammed Control Unit is more flexible.

Hardwired control versus Microprogrammed control

Branch prediction Memory dependence prediction. On the other hand, Microprogrammed Microprogranmed Units are easier to modify, decode, implement and capable of handling complex instructions. The control unit CU is a component of a computer’s central processing unit CPU that directs the operation of the processor. A controller that uses this approach can operate at high speed; however, it has little flexibility, and the complexity of the instruction set it can implement is limited.

ALU handles the mathematical and logical operations while CU sends timing and control signals to the other units to synchronize the tasks.

Microprogrammed control is a control mechanism that generates control signals by reading a memory called a control storage CS that contains control signals. Note that a control storage can be regarded as a combinational logic circuit. Leave a Reply Cancel reply. The same field configuration state assignment can be used for both of these two types of control. Microprograms were organized as a sequence of microinstructions and stored in special control memory.


A control variable refers to a binary variable that specifies micro-operations. Therefore, it has minimum flexibility. The speed of operations in Hardwired Control Unit is fast. Therefore, it conrtol easier to design, implement and midroprogrammed.

Difference Between Hardwired and Microprogrammed Control Unit –

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 microprogrmmed 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 implemented using various electronic components such as combinational logic units and gates. In additon to the above differences, the Hardwired Control Unit uses a small instruction set while theMicroprogrammed Control Unit uses a large instruction set.

The algorithm for the microprogram control unit,unlike the hardwired control unit, is usually specified by flowchart description. This architecture is preferred microprogrmamed reduced instruction set computers RISC as they use a simpler instruction set. Single-core Multi-core Manycore Heterogeneous architecture. Moreover, it is difficult to perform instruction decoding in Hardwired Control Unit than in Microprogrammed Control Unit. Hardwired control is a control mechanism contrlo generates control signals by using an appropriate finite state machine FSM.


This results in a computer that could run a complete program and require no human intervention to make hardware changes between instructions as had to be done when using only punch cards for computations before stored programmed computers with CUs were invented.

The idea of microprogramming was introduced by Maurice Wilkes in as an intermediate level to execute computer program instructions. The Control Unit can either be hardwired or microprogrammed. Outputs of the controller are organized in microinstructions and they can be easily replaced. The control memory contains control micropeogrammed. This is a truth table. Before talking about Microprogrammed Control Unit, it is important to understand some terms.

Difference Between Hardwired and Microprogrammed Control Unit

It consists of main two subsystems: She is passionate about sharing her knowldge in the areas of programming, data science, and computer systems. 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.

Previously, control units for CPUs used ad-hoc logic, and they were difficult to design.