Microprocessor

Q.       What is CPU?

Ans.: CPU: The control unit, register unit and arithmetic logic unit of a computer system are jointly known as the CPU. The CPU is the brain of a computer system. All major calculations and comparisons performed by a computer are carried out inside its CPU. The CPU is also responsible for activating and controlling the operations of other units of the computer system.

Q.       Show the logical diagram of CPU and discuss function of its components.

Ans.:

            Register Set:

·   Retain data temporarily within operation

·   Ex.: Accumulator, Instruction register, Address register, General register, Special register etc.

            Arithmetic & Logic Unit (ALU):

·   Accomplish micro operation for execute instruction.

·   Perform all logical and arithmetical tasks.

            Control Unit:

·   Control data to ALU and Register set.

·   Instruct to the ALU.

·   Control CPU and time management.

Q.       What is RISC microprocessor?

Ans.: RISC:

·         Reduced instruction set computer.

·         The microprocessor is designed using hardwired control

·         It executes at least one instruction in a cycle.

·         The instructions have simple fixed formats with few addressing modes

·         It has several general purpose resisters and large cache memory

·         The instruction set of RISC microprocessors typically includes only register to register load and store

·         Pipelining and superscalar architectures are the base methods to design a RISC processor.

Q.       What is CISC microprocessor?

Ans.: CISC:

·         Complex instruction set computer

·         The microprocessor is designed using code control.

·         Several cycles may be required to execute one instruction.

·         The instructions have variable formats with several complex addressing modes

·         It has a small number of general purpose registers

·         The instruction set of CISC microprocessor includes several instructions to access memory and CPU registers

·         Pipelining and superscalar features are not the bases to design such processors. Although, many CISC microprocessors use several features if RISCs such as: pipeline, to increase it performance.

Q.       Write short notes on: -

Ans.:  ALU: The arithmetic and logic unit or ALU is the data processing unit or the microprocessor. Functions of ALU are:

·      Arithmetic operation (addition, subtraction, multiplication and division)

·      Logical operations (OR, AND, NOT etc.)

·      Decision making

ALU is the computer’s calculator. A few current processors use multiple ALUs to attain high processing speeds. However, most microprocessors have a single ALU. The ALU makes use of temporary storage areas referred to as registers.

Q.       What do you mean by random access?

Ans.: Random access: If memory accessed in any order and access is time independent of the location being accessed, the memory is termed a random-access memory (RAM). Ferrite core and semiconductor memories are of this type.

Q.       What do you mean by Serial access?

Ans.   Serial access: If storage locations can be accessed only in certain predetermined sequence then the memory is called serial-access memory. Magnetic-tape, magnetic-bubble, and optical memories employ serial access method.