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Course Group & Folder

EE2323:Microprocessors & Computer Architecture
Spring 2013

• Course Yahoo Group – • Course Folder – \\dataserver\jinnah$\M Tahir\EE2323

Lecture 2 February 22, 2013
2/23/2013 2

Microprocessor based System
• A Microprocessor-based systems consists of central processing unit (CPU), memories, I/O Devices and other peripherals.
• CPU takes input from I/O devices such as keyboards CPU processes data in internal registers CPU sends output to I/O devices such as monitors, speakers Microprocessor (CPU) stores data and code in Memory Address Bus

Microprocessor based System
• There are three main components of microprocessor based system or computer – Central Processing Unit (CPU) – Memory Unit – I/O Devices • Microprocessor Buses • A bus is a communication pathway connecting two or more devices – Data Bus – Address Bus – Control Bus 2/23/2013 4

Control Bus

• •

CPU (µP) µ

Data Bus

I/O Devices



Microprocessor based System
• Central Processing Unit (CPU) – Brain of the computer, coordinating all the activities between different components to process data – CPU processes program instructions one by one and operates synchronously on a clock – Clock frequency determines how fast the CPU can process data • I/O Devices – Input Devices (Keyboards, mouse) – Output Devices (Monitor, speakers) 2/23/2013 5

Microprocessor based System
• Memory Unit (Main memory) – Provides storage of information – data and program instruction – Microprocessor may have a unified memory for program & data or separate program and data memories – External memories are used for storage of large program and data files. e.g. Hard disk, CDs, flash memories – Types of memories: » Random Access Memory (RAM): Volatile, data will be lost when power is off » Read-Only Memory (ROM): Non-Volatile 2/23/2013 6

Components of a Microprocessor (CPU)
• Main components of central processing unit are – Register File » CPU processes data in internal registers » Different Processors have variable number of internal registers » Size of registers can be 8-bit, 16-bit, 32-bit, 64-bit, depending on the CPU

Microprocessor Buses
• Address Bus – Addresses are placed over address bus to access memory & I/O devices – Each memory element and I/O device has a unique address – Given the address bus size n, the addressing capability of µP is 2n • Control Bus – Control signals between the CPU, Memory and I/O Devices are exchanged using control bus – e.g . Memory Read,Memory Write, interrupt signals, acknowledge 2/23/2013 8

– ALU (Arithmetic and Logic Unit)
» Processing of data is done in ALU depending upon program instruction

– PC (Program Counter)
» Also know as instruction pointer (IP), points to the address of the next instruction to be executed

– Instruction decoder ( Controller )
» Decodes instruction fetched into the CPU
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Microprocessor Buses
• Data Bus – Data bus is used for transfer of data and program code between CPU and memory , I/O devices – Data buses are bi-directional – Control signals determine direction of data transfer – Speed of data transfer between CPU and memory , I/O devices depends upon width of data bus .i.e. A 16 bit data bus will transfer data faster as compared to an 8 bit data bus

Components of a Computer
• Components of computer are CPU, main memory and I/O
Devices • Components of CPU are Program counter (PC), ALU , Register File , Instruction decoder/controller CPU PC Register File (R0 - R15) Instruction Decoder Control Bus Data Bus Address Bus

Main Memory

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I/O Devices

Microprocessor Interfacing
• To perform useful tasks microprocessor needs to be connected to other electronic devices such as memory disks, keyboards, displays , sensors • Microprocessor interfacing is how microprocessor is connected with other devices and how it...
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