SECTION I-1: Microcontrollers Versus General Purpose Microprocessor

SECTION  I-1: Micro-controllers Versus General Purpose Microprocessor

Need for micro-controllers  and contrast them with general-purpose microprocessors such as the Pentium and other x86 microprocessors. Looking at the role of micro-controllers in the embedded market plus providing some criteria on how to choose a micro-controllers.

What is the difference between a microprocessor and micro-controller?

Microprocessor  is meant the general-purpose microprocessors such as Intel's x86 family (8086m 80286, 80386, 80486, and the Pentium) or Motorola's Power PC family. These microprocessors contain no RAM, no ROM, and no I/O ports on the chip itself. For this reason, they are commonly referred to as general-purpose microprocessors.


A system designer using a general-purpose microprocessor such as the Pentium or the power PC must add RAM, ROM, I/O ports, and timers externally to make them functional. Although the addition of external RAM, ROM, and I/O ports makes these systems bulkier and much more expensive, they have the advantage of versatility, enabling the designer to decide on the amount of RAM, ROM, and I/O ports needed to fit the task at hand. This is not the case with micro-controllers. A micro-controllers has a CPU in addition to a fixed amount of RAM, ROM, I/O ports, and timer are all embedded together on one chip; therefore, the designer cannot add any external memory, I/O ports in micro-controllers makes them ideal for many applications in which cost and space are critical, In many applications, a TV remote control, there is no need for the computing power of a 486 or even an 8086 microprocessor. In many applications, the space used, the power consumed, and the price per unit are much more critical considerations than the computing power. These applications most often require some I/O operations to read signals and turn on and off certain bits. Some call these processors IBP, "itty-bitty processors". It is interesting to note that some micro-controllers manufacturers have gone as far as integrating an ADC, analog to digital converter, and other peripherals into the micro-controllers.

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