The importance of microprocessor lies in its permission to greater flexibility. More over it can be linked with sensors, measuring and switching devices and execute any industrial process.
For any computer, the main unit is called the CPU and microprocessor is the integral part of this brain. The control unit, Arithmatic logic unit and registers are what microprocessor is based upon. This single chip defines the type and the characteristics of the computer. A microprocessor may be provided with a number such as 8086, 8088, 8051, 80486 etc. Generally the microprocessors are categorically divided on the basis of the number of bits that the Arithmetic Logic unit allow to work upon at a time.
Von Neumann Processors:
Named after mathematician and early computer scientist John von Neumann, the von Neumann is generally a term given to any design model for a stored-program digital computer which involves the usage of processing unit and a separate storage location to store the given instructions and data.
The computing machines in earlier times had limited purposes. For example, a desk calculator was designed to calculate only. The example of General purpose CPU is the INTEL 8085,which is an upgrade example of Intel 8080.The essential features of such device require a +5 V supply. Produced in 1985, 8085 was a newer version of 8080.It had the same memory, executes same number of instructions with an advantage of built in clock generator and a system controller.
Dedicated or embedded Processors:
These kinds of microprocessors are used in controlling smart machines for example microwave ovens, cloth sewing machines etc .Such devices are called as micro controller devices. INTEL 8051 is another example .This device was provided with counter programs and a serial port (UART) as well a CPU, ROM, RAM and Parallel I/O ports.
Bit slices processors:
Not all the processors can cope up with the demands of applications and are not speedy enough to perform the task. For such reasons ,another type of processors are used such as Advance Micro devices 2900.This family includes 4 bits ALU'S .These are termed as Slice processors as the parts of such devices can be connected in parallel with 8 bits words ,16 bits words or 32 bits words to work along.
When there was a tremendous pressure by users on the manufacturers to cope up with demands of applications, more enhanced features processors were produced.RISC /CISC are such processors designed for that purpose.RISC is an abbreviation of reduced instruction set computers while CISC is an abbreviation for Complex instruction set computers. The RISC enables more than one instruction to be in a queue. This saves time and works ahead of time. RISC is provided with instructions that work to bring about logical and simple arithmetic problems, shift, and store etc functions. These functions involve one or two clocks to be completed as compare to others.
The advent and progress of Micro-processor systems is the requirement of time. As the time advances more, there will be more demands for modifications in these systems from the users. Each, possessing striking features of its own. Micro-processors and micro-controllers all will go through modification phases and there will be new advance versions of these systems which will be more users friendly and free to adjust according to the applications