Evolution of Microcontrollers

1. Evolution of Microcontrollers T.SRIKRISHNA, M.Sc, M.Tech, GVP
Types of Microcontrollers
Microcontrollers are divided into various categories based on memory,
architecture, bits and instruction sets. Following is the list of their types −
Bit
Based on bit configuration, the MC is further divided into three categories.
 8-bit microcontroller − This type of microcontroller is used to
execute arithmetic and logical operations like addition, subtraction,
multiplication division, etc.
For example, Intel 8031 and 8051 are 8 bits microcontroller.
 16-bit microcontroller − This type of microcontroller is used to
perform arithmetic and logical operations where higher accuracy and
performance is required.
For example, Intel 8096 is a 16-bit microcontroller.

2. Evolution of Microcontrollers T.SRIKRISHNA, M.Sc, M.Tech, GVP
 32-bit microcontroller − This type of microcontroller is generally
used in automatically controlled appliances like automatic operational
machines, medical appliances, etc.
Memory
Based on the memory configuration, the microcontroller is further divided
into two categories.
 External memory microcontroller − This type of microcontroller is
designed in such a way that they do not have a program memory on
the chip. Hence, it is named as external memory microcontroller.
For example: Intel 8031 microcontroller.
 Embedded memory microcontroller − This type of microcontroller
is designed in such a way that the microcontroller has all programs
and data memory, counters and timers, interrupts, I/O ports are
embedded on the chip.
For example: Intel 8051 microcontroller.
Instruction Set
Based on the instruction set configuration, the microcontroller is further
divided into two categories.
 CISC − CISC stands for complex instruction set computer. It allows
the user to insert a single instruction as an alternative to many simple
instructions.
 RISC − RISC stands for Reduced Instruction Set Computers. It
reduces the operational time by shortening the clock cycle per
instruction.
Classification Of Microcontroller According to Memory
Architecture
According to Memory Architecture there are two type of
Microcontroller
 Harvard Memory Architecture
 Von Neumann Memory Architecture

3. Evolution of Microcontrollers T.SRIKRISHNA, M.Sc, M.Tech, GVP
Harvard Memory Architecture: In Harvard architecture separate
storage and signal Buses are provided for different set of instructions
(program) and data.
Von Neumann architecture: In Von Neumann architecture, one Bus
is exists for both instruction and data. So, the CPU does only one
operation at a time.
It either fetches an instruction from memory, or performs read/write
operation on data. So both operations (instruction fetch and a data
operation) cannot occur simultaneously because they sharing a
common bus.
Applications of 8051 Microcontroller
The 8051 have wide range of applications, but it is mainly used for the
embedded system. Following are some applications it is used for.
1. Consumer Appliances
2. Home Appliances ( Music Instruments TVs, VCR, Video Games,
Oven)
3. Communication Systems
4. Office
5. Automobiles
6. Aeronautical and Space
7. Medical Equipment
8. Defence Systems
9. Robotics
Evolution of Micro controllers
Microcontrollers have gone through a silent evolution.
The evolution of microcontroller technology has undergone significant
change since early 1970's. Development of some popular
microcontrollers is given as follows.

4. Evolution of Microcontrollers T.SRIKRISHNA, M.Sc, M.Tech, GVP
For most embedded systems we have the choice between 4 bit, 8 bit,
16 bit and 32 bit cores.
 4 bit micro controllers are extensively used in toys.
 8 bit micro controllers are generally used in various control
applications such as position control, speed control and process
control.
 The 16 bit microcontroller are designed and developed for the
purpose of high speed control operations such as servo control
systems, robotics etc.
 32 bit microcontrollers are used in high speed operations such
as robotics, image processing , auto mobiles, Artificial
Intelligence and Communication systems.