Microcontrollers

Posted by vinod kataria on June 5, 2010

Microcontroller: Before defining Microcontroller let us talk about Microprocessor. Microprocessor:

A microprocessor is nothing but a CPU of a computer. This CPU is within the Microprocessor’s integrated Chip. The 8085 Microprocessor consist of :

1)ALU , 2) Registers, 3) Accumulater, 4) Program Counter 5) Stack Pointer, 6) Instruction register, 7) PSW Related Buses, and 9) Control & Interrupt logics.

A 8085 Microprocessor requires following additional Chips to function as computer: 1) Memory chips, 2) External Buses, 3)I/O Controllers and 4) Logic controllers such as DMA controller etc.

All the above components must be assembled together on a Board to make it a computer and then to execute a user program.

Microcontroller: After having defined the Microprocessor let us define the Microcontroller as a subset/superset of Microprocessor. This integrated chip not only contains the CPU but also has a little bit of Memory, limited I/O controllers, a specific DMA controller and Interrupt logic.

This integrated chip alone is sufficient for an application for limited requirement and limited application. This does not require additional hardware. For such applications this microcontroller itself work as user program executer (computer).

The Microcontroller is therefore looks as:

the Microprocessor looks as:

Advantages of Microcontroller over Microprocessor:

1) Reduced Size.

2) Reduced Complexity

3) Few components are required outside the controller chip.

4) Faster access to its devices.

5) Low Power consumption.

6) User friendly.

7) . Many programs are inbuilt as library functions.

9) Application oriented.

10) Capable of executing programs dedicatedly without much user intervention.

11) Achieves portability easily.

12) Best suitable for Embedded Systems.

Disadvantages:

1) Limited capacity.

2) Not suitable for general applications.

3) Limited modularity.

4) Specific Operating system required.

5) Almost no adaptability.

Above explanation categorically differentiate the Microcontroller from Microprocessor. Now a days absolutely application oriented Microcontrollers are available which have a vast user library such as LCD program, Motor control program, Keyboard Interface programs etc.

EMBEDDED SYSTEMS

Posted by vinod kataria on May 24, 2010

Embedded Systems:It is a process system which processes one or few specific processes dedicatedly and independently. The Hardware and Software utilized in these Systems are underutilized and restricted.

Embedded systems can be designed as Real time systems and /or non Real time systems. Besides these may be Portable or Non portable systems.

Hardware and Software used in an embedded system are customized such that the system will perform these operations repeatedly.

Real Time Operating Systems are used for real time Embedded systems such as Digital control module for a specific control operation(e.g. Specific opening and positioning of valve in a Control Valve, Fuel flow controllers, Dispensers etc.).

While normal Operating Systems are used for non real time systems such as Cash Registers, Point of sale terminals, RFID based monitors or controllers Etc.

Kataria