Introduction to 8051 microcontroller

                   8051 microcontroller

           

            

When we learn anything . we have two doubts why we  are learning and what we are learning .

There are millions of applications and appliances that we are using day to day life using microcontrollers

Few examples tv, tv remote, air-conditioning, Ac remote, washing machine, refrigerator, keyboard, mouse, DVD drives, USB ports, and so..in your house is full of microcontrollers the list is end less and have massive application's in real world  you not even imagine how many are that's why we are trying to learn microcontroller..

Microcontroller is a small chip which have all the components in it have advantage of microcontrollers is small in size then microprocessor...

Let's discuss the parts of the microcontroller 

First and most one processor, memory (RAM,ROM), I/O ports , serial ports, Timer's

Let's discuss one by one and first we discuss the working components then we go for example.

Processor.                                                     

    Where there is a required program then there definitely consist a processor   this 8 -bit  processor is  to be follow the instructions which we written 

Memory                                                        

We know there are two types of memory RAM and ROM ..

RAM stands for random access memory which we can write and read the data and the data inside the RAM are not permanent.

ROM( read only memory ) which we can read the data inside the ROM we unable to write. and the data inside the ROM is permanent...in 8051 microcontroller the capacity of RAM is 128 bytes ROM (4 KB)  when you seeing this numbers . yes you think that this memory is enough ?? more then enough we discuss this in later.

I/O PORT'S                                                    

used for input and output ports to connect the external device's these are 4 .8 bit I/O ports and parallel ports which  transfer multiple data at a time .used for short  distances communication...

SERIAL PORTS                                          

This type ports are used to transfer the data in serial (one by one ) this ports are used in longer communication 

TIMER'S                                                   

the timers play an important role it producing delay the delay is nothing but the time gap between two events there are two types of delays

Software delay and hardware delay 

Software delay.                                              

Here you don't need a external devices you just write a loop which will give exact time after completing loop. processor  excite the loop 

Hardware delay                                               

We use an external devices the delay is produced by timer 

Hardware delay is expensive  power consuming ..and have complexity but the main advantage for hardware delay is the delay is produced by timer so processor is free so, during the delay it can complete some other work till the completing of delay .but  in software delay processor  is busy in  excuiting  program. we can produce more number of delay so that processor won't wait till completing of that one delay

Above all this for transferring data from memory to processor we need data bus ,control bus, address bus, all this three buses called data bus...

Let's see an example for better understanding

Suppose you're making a microvan the most important thing is heating element. which is responsible for cooking food, but to control the heating element , display, showing seconds on screen , selecting of modes etc....you need memory to store the information like current temperature and selecting temperature for cook . we need input port for start or stop button and selecting temperature .. output port used for displaying seconds timer will produce time delay the moment you press start button .the processor instruct all components in right path like rotating the dish , temperature etc.

MEMORY.                                                           

 4kb of internal ROM memory approximately 4000 bytes the instructions are stored in may be 2,3 Bytes if every instruction is about 3 bytes then you able to store 3k instructions.....

RAM(128 BYTES )                                            

FOR EXAMPLE  consider a air-conditioning RAM it store the current memory 1 byte is enough for storage temperature and 1 byte is for fan speed 1 byte for cooling mode all together 3 bytes. But we have 128 bytes .

Summary                                            

8 bit processor

8 bit data bus 

8 bit alu

16 bit address bus 

4 kb internal storage 

128 bytes internal RAM 

external memory expanded upto 64 kb

4,8 -bit I/O ports all bit addressable

1 serial port ..

2,16 bit timers.

Power saving mode .

12 megahertz operating frequency 

5 volts power supply .

 Ideal and power down mode 

 i hope you got an idea about 8051 microcontroller...thank you