Many people don’t know the basic difference between a microprocessor and the microcontroller. Microprocessor is a general purpose processor like Intel 4004, Intel 8085, Intel 8086, Intel Pentium series, Motorola 6800 processor,  Zilog  Z80 general purpose processor.

Microprocessor is mainly used for processing, computing calculations. For computing calculations it has some registers internally. Very few registers are available. Calculations are done in the Arithmetic Logic Unit (ALU). The several instructions from different programs are queued for execution. These microprocessors contain no RAM, no ROM, no I/O ports, no Timers etc on the chip. For making the general purpose system, we should interface all those peripherals externally.

Microcontroller has internally some RAM, some ROM, microprocessor, Timers etc. These all components are present in single chip. But the fixed amount of on-chip ROM and RAM is very less. So to avoid this, microcontrollers can be interfaced to external off-chip ROM and off-chip RAM. For example in TV remote control, there is no need of much computing power. It performs turning on and off certain bits. If we select one channel then the previous channel bit becomes off and the present channel bit becomes on. Here no need of external memory. Here processing power is also very less.

In general, microcontroller is specifically used for the single application. Intel 8031 and Intel 8051 are the famous microcontrollers. Like inside every mouse there is a microcontroller which is used for finding the mouse position and sending it to the computer. A printer is used for getting the data from the computer and printing it. It is used for specific application only. It has a microcontroller which performs this task. Now some manufacturers are interfacing analog to digital converters also for making it more flexible.

Now you may think that if the microcontroller has all the components embedded in a single chip, then in our computers why we are using microprocessors instead of microcontrollers ?  Our Computer performs different tasks at a time. So much processing power and memory is needed for handling it. Here we are having more flexibility of adding RAM, ROM, I/P ports and timers externally to make the system functional. So we are using microprocessors. At first the microprocessors are 4 bit. Now the microprocessors are 64 bit. A 64 bit microprocessor works so much faster than other processors. These processors are high end processors. They can handle many applications.

At first microprocessors has single core. Now the quad core processors came into market last year and in few years eight core processors are also coming. Single core processor handles only one instruction at a time. Dual core processors handle one instruction in positive cycle and another instruction in negative cycle. Quad core processor handles 4 instructions at a time. So processing power and computation power is much better in quad core processor.