A WORLD INSIDE AN IC
DAKSH RAJ CHOPRA
Rules of Seminar
Students can ask any question
they want to in between the
seminar. (Just Joking :p)
A microcontroller (sometimes
abbreviated µC, uC or MCU) is a small
computer on a single integrated
circuit containing a processor core, memory,
and programmable input/output peripherals.
Microcontrollers are used in automatically
controlled products and devices, such as
automobile engine control systems,
implantable medical devices, remote
controls, office machines, appliances, power
tools, toys and other embedded systems.
CPU –CPU is the device which is employed to
fetch data, decode it and at the end complete
the assigned task successfully.
Memory –Memory chip stores all programs &
Input/output ports – I/O ports are basically
employed to interface or drive different
appliances such as- printers, LCD’s, LED’s, etc
ADC (Analog to digital converter) – ADC is employed to
convert analog signals to digital ones.
DAC (digital to analog converter) – this converter
executes opposite functions that ADC perform. This
device is generally employed to supervise analog
appliances like- DC motors, etc.
Serial Ports – These ports give serial interfaces amid
microcontroller & various other peripherals such as
Timers – A microcontroller may be in-built with one or
more timer or counters
Classification of Microcontrollers
Microcontrollers can be classified into following :-
CISC vs. RISC
Emphasis on hardware
"LOAD" and "STORE"
incorporated in instructions
Small code sizes,
high cycles per second
Transistors used for storing
Emphasis on software
reduced instruction only
Register to register:
"LOAD" and "STORE"
are independent instructions
Low cycles per second,
large code sizes
Spends more transistors
on memory registers
List of Microcontrollers
ARM core processors (from many vendors)
Atmel AVR (8-bit), AVR32 (32-bit), and AT91SAM (32-bit)
Cypress Semiconductor PSoC (Programmable System-on-Chip)
Microchip PIC, (8-bit PIC16, PIC18, 16-bit dsPIC33 / PIC24), (32-bit
NXP Semiconductors LPC1000, LPC2000, LPC3000, LPC4000 (32-bit),
LPC900, LPC700 (8-bit)
Texas Instruments TI MSP430 (16-bit)
Need of microcontroller
periodically read the temperature (analog value, is digitized by
sensor; uses 4-bit interface),
control heating according to the temperature (turn heater on/off; 1
display the current temperature on a simple 3-digit numeric display
allow the user to adjust temperature thresholds (buttons; 4 bits), and
be able to configure/upgrade the system over a serial interface.
History of Microcontrollers
The first microprocessor was the 4-bit Intel
4004 released in 1971, with the Intel 8008.
The Smithsonian Institution says TI engineers Gary
Boone and Michael Cochran succeeded in
creating the first microcontroller in 1971. The
result of their work was the TMS 1000, which
became commercially available in 1974.
Advance Microcontroller AVR
AVR was developed in the year 1996 by Atmel
The architecture of AVR was developed by Alf-
Egil Bogen and Vegard Wollan. AVR derives its
name from its developers and stands for Alf-Egil
Bogen Vegard Wollan RISC microcontroller, also
known as Advanced Virtual RISC.
The AT90S8515 was the first microcontroller
which was based on AVR architecture however
the first microcontroller to hit the commercial
market was AT90S1200 in the year 1997.
Need of Advance Microcontroller
Family of AVR
1. TinyAVR – Less memory, small size, suitable only for simpler
2. MegaAVR – These are the most popular ones having good
amount of memory (upto 256 KB), higher number of inbuilt peripherals
and suitable for moderate to complex applications.
3. XmegaAVR – Used commercially for complex applications,
which require large program memory and high speed