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Unformatted text preview: re. It’s a free download from the Intel Web site
(www.intel.com). 2.1.1 Basic Microcomputer Design
Figure 2–1 shows the basic design of a hypothetical microcomputer. The central processor
unit (CPU), where calculations and logic operations take place, contains a limited number of
storage locations named registers, a high-frequency clock, a control unit, and an arithmetic
• The clock synchronizes the internal operations of the CPU with other system components.
• The control unit (CU) coordinates the sequencing of steps involved in executing machine
• The arithmetic logic unit (ALU) performs arithmetic operations such as addition and subtraction and logical operations such as AND, OR, and NOT.
The CPU is attached to the rest of the computer via pins attached to the CPU socket in the
computer’s motherboard. Most pins connect to the data bus, the control bus, and the address bus.
The memory storage unit is where instructions and data are held while a computer program is
running. The storage unit receives requests for data from the CPU, transfers data from random
access memory (RAM) to the CPU, and transfers data from the CPU into memory. All processing of data takes place within the CPU, so programs residing in memory must be copied into the
CPU before they can execute. Individual program instructions can be copied into the CPU one at
a time, or groups of instructions can be copied together.
A bus is a group of parallel wires that transfer data from one part of the computer to another.
A computer system usually contains four bus types: data, I/O, control, and address. The data bus
Figure 2–1 Block Diagram of a Microcomputer.
data bus, I/O bus registers
Central Processor Unit
ALU CU Memory Storage
#2 clock control bus
address bus For More BS-IT Books, Notes & Assignments visit: www.bsit.zxq.net 2.1 General Concepts
Downloaded From: www.bsit.zxq.net 31 transfers instructions and data between the C...
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- Winter '13