Using LEDs, LCDs and GLCDs in Microcontroller Projects

1.3 Parts of a Microcontroller

Before explaining microcontroller architectures and programming, it is worthwhile to look at the parts of a microcontroller in more detail and understand some basic terms.

1.3.1 Address

Address is a binary pattern that is used to represent memory locations. An address bus is a collection of address lines in a processor. For example, most 8-bit microcontrollers have a 16-bit address bus, capable of addressing up to 65 536 different memory locations (0 to 65 535).

1.3.2 ALU

An arithmetic and logic unit (ALU) is part of a computer where the actual mathematical and logical operations are performed. 8-bit microcontrollers have 8-bit ALU modules. Typical operations carried out by an ALU are addition, subtraction, division, logical ANDing, ORing, Exclusive-OR and comparison. Some ALUs can also perform signed or unsigned multiplication.

1.3.3 Analogue Comparator

Some microcontrollers have built-in analogue comparator modules. An analogue comparator module is used to compare the voltage levels of two analogue signals. Although this feature is implemented in most mid-range PIC microcontrollers, it is not an important functionality.

1.3.4 Analogue-to-Digital Converter

Analogue-to-digital converter (A/D converter) is used to convert an analogue input signal into digital form, so that the signal can be processed within the microcontroller. Most mid-range PIC microcontrollers have built-in A/D converter modules. In general purpose and low-speed applications, the ...