Showing posts with label Class Notes: Microprocessor and Computer Architecture. Show all posts
Showing posts with label Class Notes: Microprocessor and Computer Architecture. Show all posts

Describe the Internal Architectures, Features, Working Principles and Registers of 8086 Microprocessor.

Internal Architecture of Intel 8086 Microprocessor

The Intel 8086, also called the iAPX 86, is a 16-bit microprocessor designed by Intel Corporation in between 1976-1978. This Intel 8086 microprocessor gave rise to the x86 architecture or 16-bit architecture. The figure given below is the internal architecture of Intel 8086 microprocessor

What are the steps followed by CPU in computer to Execute an Instruction?

CPU (Central Processing Unit):

CPU or central processing unit in computer is an electronic circuitry that carries out the instruction given by a computer program. CPU in computer execute instruction by performing basic arithmetic, logical, control and I/O operations as required per instruction. CPU in computer is considered to be the brain of the computer. The speed and efficiency of a computer mostly depends on it's CPU.

Define Instruction Set Architecture. What are the main objectives of ISA in computer systems.

Instruction Set Architecture (ISA):

An instruction set is the interface between a computer's software and its hardware, and thereby enables the independent development of these two computing realms. ISA is the set of basic instructions that a processor understands.

ISA includes functional definition of operations, modes, and storage locations supported by hardware and precise description of how to invoke, and access them.

Suggested Reading:
1. What are CISC (Complex Instruction Set Computer) & RISC (Reduced Instruction Set Computer)? What are the differences between CISC & RISC?

What are CISC & RISC? What are differences between CISC and RISC?

The instruction set or the instruction set architecture (ISA) is the set of basic instructions that a processor understands. The instruction set is a portion of what makes up an architecture.

Two initial types of instruction set architecture are CISC (Complex Instruction Set Computer) and RISC (Reduced Instruction Set Computer).

What is control unit? What are the functions of control unit?

Control Unit:

Control unit co-ordinates the transfer of data between registers of CPU or microprocessor and ALU. Control unit serves the instructions for ALU. Along with this, control unit, as its name implies, controls every other parts of the machine, their co-ordinations, traffic etc.

Thus control unit controls the complete work-flow of the CPU. But control unit doesn't take inputs, give outputs, process data or store data itself, what control unit do is, it controls these operations when they are performed by respective devices.

Discuss the organization and functions of ALU or Arithmetic & Logic Unit

Arithmetic and Logic Unit (ALU):

Arithmetic and Logic Unit is a like a calculator to a computer. ALU performs all arithmetic operations along with decision making functions. In modern CPU or Microprocessors, there can be more than one integrated ALU to speed up arithmetical and logical operations, such as; integer unit, floating point unit etc.

What are memory mapped I/O and isolated I/O? What are differences between memory mapped I/O and isolated I/O?

Memory Mapped I/O and Isolated I/O are two methods of performing input-output operations between CPU and installed peripherals in the system. 

Memory Mapped I/O:

Memory mapped I/O uses the same address bus to connect both primary memory and memory of hardware devices (registers). Memory and registers of I/O devices gets assigned values, thus when CPU try to access an address value, it can either from memory or from registers of I/O devices. Memory mapped I/O thus helps in utilizing the same instruction for accessing or addressing both primary memory and I/O device memory locations. 

Addressing 5 ROM Chips, Each of 4 KB Using 74LS138 Decoder

Addressing 5 ROM Chips, Each of 4 KB Using 74LS138 Decoder:

The following diagram is representing the addressing of 5 ROM chips using 74LS138 where each chip is of 4 KB.

How can we interface the microprocessor with analog world? Explain with necessary figure.

Interfacing the Microprocessor with Analog World: As computer used digital binary values whereas we have physical variables, a step by step process is used to convert the physical variable to binary data and again to physical variable. The figure is given below

How can you control LEDs using microprocessor via 82C55A PPI? Draw the interface diagram & write the necessary assembly codes.

Controlling LEDs Using Microprocessor VIA 82C55A:

What are the purpose of using command byte A and command byte B on 82C55A? Explain with suitable example.

Purpose of Using Command Byte A: Command byte A is used select modes, working functions of the ports. So the importance of using command byte A is that we can define on which mode it will be working on and which port will be used for which function such as input or output.

For example, consider the following bit format

What will be the arrangement of ports on 82C55A PPI for the following bit format of command byte A, 10000010

The given bit format is as follows,


Arrangement of Ports Due to Given Bit Format:

What will be the bit format of command byte A in 82C55A PPI for these arrangement, (i) Mode 0, Port A as input, port B and port C as output. (ii) Mode 1, port A as output, port B as input.

(i) Required Bit Format of command byte A: 

Draw the command byte A and command byte B of 82C55A PPI.

Command Byte A and Command Byte B:

Draw the pin-out diagram of 82C55A PPI. How many modes you can select on 82C55A PPI? Explain.

Pin-Out Diagram of 82C55A:

What is handshaking? Write a suitable example for handshaking with necessary assembly codes.


Handshaking is a I/O control method to synchronize I/O devices with the microprocessor. As many I/O devices accepts or release information at a much slower rate than the microprocessor, this method is used to control the microprocessor to work with a I/O device at the I/O devices data transfer rate.

Write the differences between Isolated I/O and Memory Mapped I/O.

Memory Mapped I/O and Isolated I/O are two methods of performing input-output operations between CPU and installed peripherals in the system. Memory mapped I/O uses the same address bus to connect both primary memory and memory of hardware devices. Thus the instruction to address a section or portion or segment of RAM can also be used to address a memory location of a hardware device.

On the other hand, isolated I/O uses separate instruction classes to access primary memory and device memory. In this case, I/O devices have separate address space either by separate I/O pin on CPU or by entire separate bus. As it separates general memory addresses with I/O devices, it is called isolated I/O.

Define port? Differentiate fixed port addressing and variable port addressing.

          Port : A port is an adapter which enables a system to communicate with its input/output devices. Using port user can connect I/O devices and use them. There various types of port such as parallel port, serial port etc.

            Differences Between Fixed Port and Variable Port Addressing

Write about hamming technique of error detection and correction in the case of a 4-bit data.

Hamming Technique (7,4) : In this case, we will have 4 bits of data and we will add 3 bits of redundant with the data by calculating the 4-bit data. For example, taking a 4-bit data as,

The encoder will encode the data as follows

Write about a way to detect error./a single bit error/Write about parity check method.

Error Detection or Parity Check Method : A general way to detect errors is to append a special bit to every word. One popular technique employs a single check bit called parity bit. The parity bit is append to an n-bit word X = x0, x1,....., xn-1  to