©2008 The McGraw-Hill Companies, Inc. All rights reserved. Digital Electronics Principles & Applications Seventh Edition Chapter 13 Computer Systems Roger L. Tokheim ©2008 The McGraw-Hill Companies, Inc. All rights reserved.

INTRODUCTION Elements of a System Computer Organization Computer Peripheral Devices MPU Based System Serial/Parallel Data Transmission Programmable Logic Controller Microcontrollers Digital Signal Processing

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Elements of a System (Review) Control InputStorageProcessingStorageOutput

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Computer Organization - Classical MemoryOutputInput Arithmetic and Logic Control

©2008 The McGraw-Hill Companies, Inc. All rights reserved. QUIZ B OutputInput C A Q#1- In classical computer organization, the block labeled A would be the ___ section. ANS: control Q#2- In classical computer organization, the block labeled B would be the ___ section. ANS: memory Q#3- In classical computer organization, the block labeled C would be the ___ section. ANS: ALU

©2008 The McGraw-Hill Companies, Inc. All rights reserved. CPU and Internal Memory Output Input Input/Output Storage Internet, network, wireless or modem Fax Computer Peripheral Devices Monitor (CRT or LCD) Television Printer Speaker Plotter Keyboard Mouse Joystick Paddles Graphics tablet Microphone Light pen Scanner Bar code reader Strip reader Various Sensors Digital Camera Floppy disk drive Hard disk drive Optical disc drive Tape unit Flash memory device

©2008 The McGraw-Hill Companies, Inc. All rights reserved. QUIZ 1.Both CRT and thin-screen (LCD) monitors are classified as __________ (output, storage) peripheral devices in a computer system. output 2. Both hard and floppy disk drives and well as CD-ROM drives are classified as __________ (output, storage) peripheral devices in a computer system. storage 3. Both the keyboard and a mouse are classified as __________ (input, output) peripheral devices in a computer system. input 4. A modem is classified as an storage peripheral device in a computer system. (True or False) False

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Microcomputer System Block Diagram MPU The MPU is the heart of the system ROM The ROM contains programs and permanent data RAM The RAM contains temporary data (and programs) Input ports The input ports connect to devices such as keyboards Output ports The output ports connect to devices such as printers The address bus is unidirectional The data bus is bidirectional The control bus is unidirectional

©2008 The McGraw-Hill Companies, Inc. All rights reserved. QUIZ 1. In a microcomputer system, the ____ (MPU, RAM) is considered to be the center of operations directing the other sections. MPU (microprocessor unit) 2. In a microcomputer system, the ________ (data bus, address bus) is bidirectional so information can pass to and from the MPU. data bus 3.In a microcomputer system, both the address bus and the control bus are unidirectional paths for the MPU to direct memory, input ports, and output ports. (True or False) True

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Reading input data 1. The MPU places an input address on the bus 2. The MPU asserts a READ signal on the control bus 3. The addressed port puts its data on the bus ROM RAM Input ports Output ports MPU 4. The data is stored in the MPU MPUIN

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Writing output data 1. The MPU places an output address on the bus 2. The MPU asserts a WRITE signal on the control bus 3. The MPU places the data on the bus ROM RAM Input ports Output ports MPU 4. The data is written to the output port Output ports OUT

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Serial/Parallel Data Conversion Serial in Serial out Shift registers can be used to convert from serial-to-parallel or the reverse from parallel-to-serial Serial in Parallel out Serial out Parallel in Parallel in Parallel out

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Bit 0Start bitBit 1Bit 2Bit 3Bit 4Bit 5Bit 6Bit 7Stop Bit UART RS232 Driver To modem Transmitter Receiver Control Serial data transmission is relatively slow! A UART receives bytes from the data bus and transmits them one bit at a time.

©2008 The McGraw-Hill Companies, Inc. All rights reserved. UART RS232 to Logic Level From modem Transmitter Receiver Control Here, the UART assembles bits from the serial port and places them on the data bus one byte at a time Parallel data transmission is relatively fast!

©2008 The McGraw-Hill Companies, Inc. All rights reserved. QUIZ 1.The transfer of data over a single path, one bit after the other, is called __________ (serial, single-channel codec) transmission. serial 2. The transfer of data over multiple paths, many bits at once, is called __________ (multipactor, parallel) transmission. parallel 3. A(n) __________ (AND gate, UART) IC can send and receive serial and parallel data. UART 4. Generally, serial transfer of data is faster than parallel data transmission. (True or False) False

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Programmable Logic Controllers PLCs are heavy-duty computer systems used for machine control. PLCs must be rugged to withstand the rigors of a chemical, warehouse/storage, or assembly line environment. PLCs use MODULAR organization. Input Sensors - pressure - mechanical - optical -magnetic A/D converters Motors Solenoids Pneumatic devices D/A converters Power Supply Programming Module Memory Processing Module CPU Output Module Input Module

©2008 The McGraw-Hill Companies, Inc. All rights reserved. QUIZ 1. A(n) __________ (MCU, PLC) is a heavy duty computer system used for machine control. PLC (programmable logic controller) 2. Programmable logic controllers (PLCs) must be rugged to withstand the rigors of a chemical, warehouse, or assembly line environment. (True or False) True 3. The typical input device to a PLC system might be an A/D converter or pressure/optical/magnetic sensor instead of a keyboard and mouse. (True or False) True 4. The typical output device from a PLC system might be a monitor or printer and not a D/A converter, motor or solenoid. (True or False) False

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Microcontrollers A microcontroller is considered a “computer on a chip.” A microcontroller IC contains a CPU, RAM, ROM or EEPROM, a clock, and input/output capabilities. Microcontrollers are: Very inexpensive Commonly preprogrammed and embedded in products Commonly used to perform control functions Manufactured in huge quantities NOT used as the CPU in general purpose computers Microcontroller-based systems have much less semiconductor memory (RAM, EEPROM), cost less, use less printed circuit board space, and perform fewer commands than microprocessor based systems.

©2008 The McGraw-Hill Companies, Inc. All rights reserved. QUIZ 1. A __________ (microcontroller, PLD) IC is considered close to a “computer on a chip.” microcontroller 2. A microcontroller IC is an expensive unit used in only the highest priced computer workstations. (True or False) False 3. Microcontrollers are manufactured in huge quantities and are very inexpensive. (True or False) True 4. A microcontroller contains a CPU, RAM, ROM or EEPROM, a clock, and some input/output capabilities. (True or False) True 5. Inexpensive microcontrollers are commonly embedded in products to perform control functions. (True or False) True

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Digital Signal Processing System Block Diagram A/D Mem- mory DSPD/A x 2 DSPA/D Mem- mory D/A

©2008 The McGraw-Hill Companies, Inc. All rights reserved. QUIZ DSP AB C Q#1- The digital signal processor (DSP) is a microprocessor-like IC that can be programmed to condition or enhance signals. (T or F) ANS: True Q#2- The block labeled A in the DSP system is a(n) ___ (A/D, D/A) converter. ANS: A/D Q#3- The block labeled B in the DSP system is a ___ (memory, microprocessor) device. ANS: memory Q#4- The block labeled C in the DSP system is a ___ (D/A converter, printer interface device). ANS: D/A converter

©2008 The McGraw-Hill Companies, Inc. All rights reserved. Digital Signal Processing Digital Signal Processors are used in many electronic devices today, such as: MP3 players, DVD players, modems, cellular phones, and digital cameras. Digital Signal Processors: Are designed to quickly perform many multiplications and additions per second Are used to consistently and reliably change the characteristics of a digital signal Can process signals in real-time or ‘off-line’ Are NOT used as the CPU in general purpose computers

©2008 The McGraw-Hill Companies, Inc. All rights reserved. REVIEW Elements of a System Computer Organization Computer Peripheral Devices MPU Based System Serial/Parallel Data Transmission Programmable Logic Controller Microcontrollers Digital Signal Processing