Microprocessors and Microcontrollers

The first question that comes in one’s mind is “What is a microprocessor?”. Let us start with a more familiar term computer. A digital computer is an electronic machine capable of quickly performing a wide variety of tasks. They can be used to compile, correlate, sort, merge and store data as well as perform complex calculations at much faster rate than human being by means of stored instructions. Historically, digital computers have been categorized according to the size using the words large, medium, minicomputer and microcomputer. In the early years of development, the emphasis was on large and more powerful computers. Large and medium sized computers were designed to solve complex scientific and engineering problems. As the technology has advanced, the face of the computer has changed gradually and it became possible to build the entire central processing unit (CPU) on a single-chip known as microprocessor. A CPU with its related timing functions on a single chip known as microprocessor. A microprocessor combined with memory and input/output devices forms a microcomputer. The microcomputer is making an impact on every activity of mankind. It is being used in almost all control applications.

A microcomputer, is merely an assembly of devices whose sole task is to ensure that the instruction desired are indeed carried out properly and to allow the microprocessor to communicate with the real world, i.e. the user environment. A microcomputer which does nothing other than manipulate data present within itself, will not be of much use to anyone. In order to do something meaningful, data being manipulated should depend on inputs provided to the microprocessor by the user. Similarly, the data manipulations being carried out by the microprocessor would be completely meaningless unless the results of these manipulations affect things outside the microcomputer itself. Therefore, a microcomputer is an assembly of devices including a CPU, which manipulate data depending on one or more inputs and according to a program, in order to generate one or more output.

A µP does not have enough memory for program and data storage, neither does it has any input and output devices. Thus when a µP is used to design a system, several other chips, such as memory chips and input/output ports, are also used to make up a complete microcomputer system. For many applications, these extra chips imply additional cost and increased size of the product and may not be suitable for the application. A microcontroller is a chip consisting of a microprocessor, memory and input/output ports. The first µP was introduced in 1971 by Intel Corporation. This was the Intel 4004, a processor on a single chip. It had the capability of performing simple arithmetic and logical operations. It also had a control unit which could perform various control functions like fetching an instruction from the memory, decoding it and generating control signals to execute it. It was a 4 bit µP operating on 4 bits of data at a time.

MOODLE Webpage: https://ravivarmans.gnomio.com

Syllabus (Download)

MASM Assembler and DOSBox (Download)

MPI Lab (8086) Experiments Using MASM (Download)

Lecture Notes

I, II. 8086 Introduction, ALP, Memory Interfacing (Download)

III. 8086 Digital IO Interfacing, Interrupts and PIC (Download)

IV. The 8051 Architecture (Download)

V. 8051 Digital Interfacing and Serial Data Transfer Schemes (Download)


  1. 8086 Arithmetic and Logic Instructions (Download)
  2. 8086 Shift and Rotate Instructions (Download)
  3. 8086 Program Control Instructions (Download)
  4. 8086 String Instructions (Download)
  5. 8086 Assembly Language Programming (Download)
  6. 8086 Memory Interfacing (Download)
  7. 8086 Digital IO Interfacing (Download)
  8. 8086 Interrupts and Programmable Interrupt Controllers (Download)
  9. 8051 Architecture (Download)

Midterm Question Papers and Solution Manuals
Midterm 1: Question PaperSolution Manual
Midterm 2: Question Paper – Solution Manual

Previous Year University Question Papers (Download)