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Computing Systems. EC4012PA PIC 18F4520. Chapter 1. Introduction. What is a Computer?. Processor Input Devices Output Devices Memory Devices. Processor. A processor is also called the central processing unit (CPU) . The processor consists of at least the following 3 components:
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Computing Systems EC4012PA PIC 18F4520
Chapter 1 Introduction
What is a Computer? • Processor • Input Devices • Output Devices • Memory Devices
Processor • A processor is also called the central processing unit (CPU). • The processor consists of at least the following 3 components: • A register • Arithmetic logic unit (ALU). • Control unit.
Microprocessor • is a processor in a single ic chip • a microcomputer is a computer that uses a micro-processor as its CPU. • is referred to as 4-bit, 8-bit, 16-bit, 32-bit, or 64-bit. • word length of the microprocessor.
Microprocessor • is not designed to deal with I/O. • interface chips are needed. • External memory chips are needed to hold programs and data • Glue logic is required to interface with the memory chips, • Peripheral chips are needed to interface with I/0 devices.
What is a Microcontroller ? CPU Timer/Counter UART ADC, DAC DMA I/O, Serial, Parallel Ports Memory 7
Address Bus Memory CPU I/O Clock Block Diagram of a Microcontroller ALU Register Control Input Devices Output Devices RAM [Data] ROM [Program] Stack Data Bus Control Bus
Common characteristics of Microcontroller • “Embedded” inside the products we use everyday. • “Dedicated” to one task / one specific program • Designed for “low-cost, small, low-power performance”.
Microcontroller is Everywhere • Consumer Market – includes home appliances: • washing machines, • TV remotes, • MP3 players, • VCR and refrigerator
Microcontroller is Everywhere • Automotive market • remote keyless entry, • antilock braking and • air bags
Microcontroller is Everywhere • Office automation • PCs, • keyboards, • mouse, • modem, sound card, • copiers, scanner and printers
Microcontroller is Everywhere • Telecommunications • cellular phones, • PSPs, • pagers and • answering machines
Microcontroller is Everywhere • Industrial products • door locks in hotel rooms, • battery chargers and • industrial machinery
Memory • Programs and data are stored in memory in a computer. • A computer may contain: • semiconductor ; • magnetic (harddisk); and • optical (cdrom, DVD).
Memory • Semiconductor memory can be further classified into two major types: • random access memory (RAM) and • read-only memory (ROM).
RAM • Volatile - cannot retain data in the absence of power. • also called read write memory. • Reading memory is nondestructive. • Writes data will overwrite the old data.
RAM • Two types of RAM technology: • static RAM (SRAM) and • dynamic RAM (DRAM).
ROM • Read_Only memory is non-volatile , it retain data in the absence of power. • Data stored in these chips is either • unchangeable or • requires a special operation to change.