FMA Unit 1.2 8051 Microcontroller Architecture

8051 Microcontroller Architecture

The 8051 Microcontroller is one of the basic type of microcontroller, designed by Intel in 1980’s. This microcontroller was based on Harvard Architecture and developed primarily for use in embedded systems technology.

A. Central Processor Unit (CPU)

·       The CPU is the brain of any processing device of the microcontroller.

·    It monitors and controls all operations that are performed on the Microcontroller units.

·   The User has no control over the work of the CPU directly.

·   It reads program written in ROM memory and executes them and do the expected task of that application.

B. Memory

·  The Program memory (ROM) is used to store the program of the microcontroller. This program tells microcontroller to do specific tasks.

·  The data memory (RAM) is used to store data temporarily for operation.

·  8051 microcontroller has 4KB program memory (ROM) and also 128 bytes of data memory (RAM).

C. Control Bus

Basically Bus is a collection of wires which work as a communication channel or medium for transfer of Data. It has two types:-

·    Address Bus: Microcontroller 8051 has a 16 bit address bus for transferring the data. It is used to address memory locations and to transfer the address from CPU to Memory of the microcontroller.

·   Data Bus: Microcontroller 8051 has 8 bits of the data bus, which is used to carry data of particular applications.

D. Input/Output Port

·   Microcontroller is used in embedded systems to control the various operations of machines. Therefore, to connect it to other machines, devices or peripherals I/O interfacing ports are required.

·   For this purpose microcontroller 8051 has 4 input, output ports to connect it to the other peripherals

E. Timers/Counters

·       8051 microcontroller has two 16 bit timers and counters.

·       These counters are again divided into a 8 bit register.

·       The timers are used for measurement of intervals to determine the pulse width of pulses.

F. Interrupts

·    Interrupt is a subroutine call that interrupts of the microcontrollers main operations or work and causes it to execute any other program, which is more important at the time of operation.

·     The Microcontroller 8051 can be configured in such a way that it temporarily terminates or pause the main program at the occurrence of interrupts. When a subroutine is completed, then the execution of main program starts.

·       Generally five interrupt sources are-

v  INTO

v  INT1

v  TFO

v  TF1

v  R1/T1

G. Oscillator

·    The microcontroller requires clock pulses for its operation, so it has an on-chip oscillator which works as a clock source for CPU.

·     The output pulses of oscillator are stable. Therefore, it enables synchronized work of all parts of the Microcontroller.

 

 

Applications of 8051 Microcontroller

Some of the applications of 8051 is mainly used in daily life & industrial applications also some of that applications are shown below

• Light sensing and controlling devices
• Temperature sensing and controlling  devices
• Fire detection and safety devices
• Automobile applications
• Defense applications