Using LEDs, LCDs and GLCDs in Microcontroller Projects

1.1 Microcontrollers and Microprocessors

A microcontroller is basically a single chip computer, generally requiring no external components. A microprocessor differs from a microcontroller in many ways. Perhaps the main difference is that a microcontroller can function as a computer without the need of any external hardware. A microprocessor, on the other hand, is just the CPU of a computer, and requires several other external components before it becomes a useful computer. Because a microcontroller consists of a single chip, its power consumption is low. The development of a microcontroller based system is also easy, as the processing hardware consists of a single chip. Perhaps the only advantage of a microprocessor over a microcontroller is that a microprocessor can easily be expanded to have more memory or I/O. The expansion of microcontrollers is more difficult and a different model is usually chosen when higher performance, more memory or more I/O are required.

Figure 1.1 shows the structure of a computer, built using a microprocessor. Here the hardware consists of several components, all attached to the microprocessor chip. The structure of a microcontroller based computer is shown in Figure 1.2. The advantages of using a microcontroller instead of a microprocessor are clear when Figures 1.1 and 1.2 are compared.

Figure 1.1 Structure of a microprocessor based computer

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