Description of block-diagram of 8051
Hello friends,
I think many of you are enjoy during reading of my last post on topic "introduction of micro-controllers".now in this post i am going to describe the block diagram of 8051 .starting with the practical knowledge of bolcks which is attached in this block diagram,in last of this post i will tell you whole functionality of block diagram as you see there is two memory used in block diagram one is ROM(4K byte) and other is RAM(128 byte),ROM stand READ ONLY MEMORY it is nonvolatile memory .non-volatile means permanently storage of data,data store in this type of memory can not change by user .The size of ROM is 4K byte ,in one byte there is 8bit or we can say 2Nibble or one word. 1kilobyte is equal to 1000bytes so 4kilobytes is equal to 4000byte,so the total capacity of ROM is 4000bytes. ROM is contains programs and information essential to operation of computer. RAM stand "RANDOM ACCESS MEMORY" it is volatile memory means user can change the data store in this type of memory ,sometimes it is called read/write memory,data storage is not permanently if poower is off then data store in this memory is lost. Its total capacity of storing data is 128 bytes. RAM is used by the computer for temporary storage of program that is running.
I/O PORTS also attached in block diagram,friend as i give example in my last post which is related to computer working,computer takes input from the keyboard,mouse,the same concept involved here , we give input to controller by the I/O ports ,there is four I/O ports that is PORT0,PORT1,PORT2,PORT3.we use these ports for giving input and taking output from controller or we attache our peripheral to these ports,for control peripheral by micro-controller.
Next blocks attached to block diagram are Timer0 & Timer1 ,serial port,interrupt control,bus control.we use Timer0 & Timer1 for generating time delay,suppose if we want to blink LED in interval of one second then we use timers,we can also generate delay with the help of registers but delay is not accurate ,if we want accuracy then prefer timers.we use serial ports if we want to communicate our controller to PC,to other controllers,to any others module like wireless module,RF module etc,then we can easily established connection through serial port.Bus control is used for controlling the buses which are present in micro-controller ,we use buses only for transfer of data from one place to other place ,just I can say that buses are used for communication purpose.interrupt control we discuss in more detail in next post ,simply here we consider that interrupt occurs when if any peripheral wants its service during program,it simply send inteerupt signal to controller for their services.
In this block diagram description post my main aim is to tell you what are the practical use of I/O PORTS,TIMERS,SERIAL PORTS,MEMORY,BUS, because theoretical things are already given in books.now i want to give you whole functionality of block diagram in few lines .The function of CPU is to execute(process)information stored in memory,the function of I/O devices is to provide a means of communicating with CPU.the CPU is connected to memory and I/O through strip of wire called bus.the bus carries information from place to place inside a computer.In every computer there are three types of buses :address bus,databus,control bus.device such as memory or I/O to be recognised by the CPU,it must be assigned an address.the address assigned to a given device must be unique,no two devices are allowed to have the same address.The CPU puts the address on address bus and decoding circuitry finds device,then CPU uses the data bus either to get data from that device or to send data to it.The control buses to provide read or write signals to the device to indicate if the CPU is asking for information or sending it information.
from my next post i will suggest you how to build a project with the help of 8051 and also teach you how to make program in assembly and c language .Thanks every one for reading my post .
regards
Raushan Kr.
