MICROOCESSORS AND MICROCONTROLLER:

Computer: Computer is a multiprogram device that reads binary instructions from memory, accepts binary data as input, processes data according to instruction given and provides result as output.

Instructions: These are the commands given to the computer to perform specified task.

Program: Set of instructions given to the computer to perform specifiedtask is called program .

Hardware:Physical components present inside a computer is called Hardware.CPU- Central processing unit:

This is the unit within computer which performs arithmetic and logical computations and all control functions.ALU- Arithmetic and logical unit: This unit performs all arithmetic and logical operations.

Control unit: This unit produces various control signals required in the computer.

Microcontrollers & Embedded Processors

• Microprocessors, such as Intel Pentium and Motorola 68000 contain no appreciable RAM or ROM and are referred to as general purpose microprocessors. External devices must be connected to make them functional and useful.

• Microcontrollers contain in-chip RAM, ROM and other peripherals making them ideal for small, inexpensive applications.

Microprocessor:This is powerful IC chip which contains whole CPU with ALU and timing unit.Bit length: This is the number of bits that microprocessor can manipulate at a time.

Different microprocessors are ,Intel 4004-4 bit microprocessor Intel 8085-8 bit microprocessorIntel 8086,80186,80286 etc -16 bit microprocessorIntel 80386,80486,80586(Pentium)-32 bit microprocessor

Microcomputer: A microprocessor connected to memory and I/O devices is called microcomputer.Microcontroller:This is single chip microcomputer which contains microprocessor,memory and I/O ports within one chip.

A microcontroller contains microprocessor and one or more of the following components.

Memory.I/O portsAnalog and Digital converter Digital to Analog converterTimers and counters

Microcontroller applications: In home appliances such as Refrigerators,washing machines, microwave ovens etc.Automobile enginesIndustrial applications.Biomedical instruments Miltary applicationsTraffic controlling etc.

microprocessors microcontrollers

Has ALU and timing unit Has ALU,timing unit, memory I/O port, timers,counters etc.

Normally pins are unifunctional Most of the pins are multifunctional

Few bit related instructions Many bit related instructions

Microprocessor based design requires more hardware

Microcontroller based design requires less hardware

Difference between microprocessors and microcontrollers:

RISC CISC1. Instructions take one or two cycles. 1. Instructions take multiple cycles.2.Only load /store instructions are used to access memory

2. In addition to load/store memory access is possible with other instructions also.

3.Instructions executed by hardware 3. Instructions executed by microprogram.4.Fixed format instructions 4.Variable format instructions5.Few addressing modes 5. Many addressing modes6.Few instructions 6.Complex instruction set7.Multiple register bank 7.Single register bank

RISC and CISC machines:RISC means reduced instruction set computers . Example PIC 16F87XCISC means complex instruction set computers. Example Intel 8051Comparison of RISC and CISC

Von neuman architecture Harvard architecture

Single address and data bus is used to connect program memory(ROM)& data memory(RAM)

Separate buses are used for connecting program memory(ROM)& data memory(RAM)

Accessing from data memory and program memory can not be done in parallel

Accessing from data memory and program memory can be done in parallel

Speed of execution is slow Speed of execution is fast

Von neuman and Harvard architecture:

Programming languages:

1.machine language: In this language binary codes are used to write program.2. Assembly language : In this mnemonics are used for writing programs.

3. High level language: In this statements are used to write programs. Assembler:

This is a software which converts assembly language program, to machine code.Compiler:

This is a software which converts high level language program to machine code.