- •Objectives
- •Embedded Microcomputer Applications
- •Microcomputer and Microcontroller Architectures
- •Digital Hardware Concepts
- •Voltage, Current, and Resistance
- •Diodes
- •Transistors
- •Mechanical Switches
- •Transistor Switch ON
- •Transistor Switch OFF
- •The FET as a Logic Switch
- •NMOS Logic
- •CMOS Logic
- •Mixed MOS
- •Logic Symbols
- •Tri-State Logic
- •Timing Diagrams
- •Multiplexed Bus
- •Loading and Noise Margin Analysis
- •The Design and Development Process
- •Chapter One Problems
- •2 Microcontroller Concepts
- •Organization: von Neumann vs. Harvard
- •Microprocessor/Microcontroller Basics
- •Microcontroller CPU, Memory, and I/O
- •Design Methodology
- •Introduction to the 8051 Architecture
- •Memory Organization
- •CPU Hardware
- •Oscillator and Timing Circuitry
- •The 8051 Microcontroller Instruction Set Summary
- •Direct and Register Addressing
- •Indirect Addressing
- •Immediate Addressing
- •Generic Address Modes and Instruction Formats
- •Address Modes
- •The Software Development Cycle
- •Software Development Tools
- •Chapter Two Problems
- •Timing Diagram Notation Conventions
- •Rise and Fall Times
- •Propagation Delays
- •Setup and Hold Time
- •Tri-State Bus Interfacing
- •Pulse Width and Clock Frequency
- •Fan-Out and Loading Analysis—DC and AC
- •Calculating Wiring Capacitance
- •Fan-Out When CMOS Drives LSTTL
- •Transmission Line Effects
- •Ground Bounce
- •Logic Family IC Characteristics and Interfacing
- •Interfacing TTL Compatible Signals to 5 Volt CMOS
- •Design Example: Noise Margin Analysis Spreadsheet
- •Worst-Case Timing Analysis Example
- •Chapter Three Review Problems
- •Memory Taxonomy
- •Secondary Memory
- •Sequential Access Memory
- •Direct Access Memory
- •Read/Write Memories
- •Read-Only Memory
- •Other Memory Types
- •JEDEC Memory Pin-Outs
- •Device Programmers
- •Memory Organization Considerations
- •Parametric Considerations
- •Asynchronous vs. Synchronous Memory
- •Error Detection and Correction
- •Error Sources
- •Confidence Checks
- •Memory Management
- •Cache Memory
- •Virtual Memory
- •CPU Control Lines for Memory Interfacing
- •Chapter Four Problems
- •Read and Write Operations
- •Address, Data, and Control Buses
- •Address Spaces and Decoding
- •Address Map
- •Chapter Five Problems
- •The Central Processing Unit (CPU)
- •External Data Memory Cycles
- •External Memory Data Memory Read
- •External Data Memory Write
- •Design Problem 1
- •Design Problem 2
- •Design Problem 3
- •Completing the Analysis
- •Chapter Six Problems
- •Memory Selection and Interfacing
- •Preliminary Timing Analysis
- •Introduction to Programmable Logic
- •Technologies: Fuse-Link, EPROM, EEPROM, and RAM Storage
- •PROM as PLD
- •Programmable Logic Arrays
- •PAL-Style PLDs
- •Design Examples
- •PLD Development Tools
- •Simple I/O Decoding and Interfacing Using PLDs
- •IC Design Using PCs
- •Chapter Seven Problems
- •Direct CPU I/O Interfacing
- •Port I/O for the 8051 Family
- •Output Current Limitations
- •Simple Input/Output Devices
- •Matrix Keyboard Input
- •Program-Controlled I/O Bus Interfacing
- •Real-Time Processing
- •Direct Memory Access (DMA)
- •Burst vs. Single Cycle DMA
- •Cycle Stealing
- •Elementary I/O Devices and Applications
- •Timing and Level Conversion Considerations
- •Level Conversion
- •Power Relays
- •Chapter Eight Problems
- •Interrupt Cycles
- •Software Interrupts
- •Hardware Interrupts
- •Interrupt Driven Program Elements
- •Critical Code Segments
- •Semaphores
- •Interrupt Processing Options
- •Level and Edge Triggered Interrupts
- •Vectored Interrupts
- •Non-Vectored Interrupts
- •Serial Interrupt Prioritization
- •Parallel Interrupt Prioritization
- •Construction Methods
- •10 Other Useful Stuff
- •Electromagnetic Compatibility
- •Electrostatic Discharge Effects
- •Fault Tolerance
- •Software Development Tools
- •Other Specialized Design Considerations
- •Thermal Analysis and Design
- •Battery Powered System Design Considerations
- •Processor Performance Metrics
- •Device Selection Process
- •Power and Ground Planes
- •Ground Problems
- •11 Other Interfaces
- •Analog Signal Conversion
- •Special Proprietary Synchronous Serial Interfaces
- •Unconventional Use of DRAM for Low Cost Data Storage
- •Digital Signal Processing / Digital Audio Recording
- •Detailed Checklist
- •Define Power Supply Requirements
- •Verify Voltage Level Compatibility
- •Check DC Fan-Out: Output Current Drive vs. Loading
- •Verify Worst Case Timing Conditions
- •Determine if Transmission Line Termination is Required
- •Clock Distribution
- •Power and Ground Distribution
- •Asynchronous Inputs
- •Guarantee Power-On Reset State
- •Programmable Logic Devices
- •Deactivate Interrupt and Other Requests on Power-Up
- •Electromagnetic Compatibility Issues
- •Manufacturing and Test Issues
- •Books
- •Web and FTP Sites
- •Periodicals: Subscription
- •Periodicals: Advertiser Supported Trade Magazines
- •Programming Microcontrollers in C, Second Edition
- •Controlling the World with Your PC
- •The Forrest Mims Engineers Notebook
- •The Forrest Mims Circuit Scrapbook, Volumes I and II
- •The Integrated Circuit Hobbyist’s Handbook
- •Simple, Low-Cost Electronics Projects
223APPENDIX A
Hardware Design Checklist
12. Deactivate Interrupt and Other Requests on Power-Up
Interrupt, DMA, and other edge sensitive input requests should be disabled upon power up to minimize the chance that a spurious event will be pro cessed when the system is turned on.
13. Electromagnetic Compatibility Issues
Signals that enter and leave the printed circuit boards should be filtered to reduce the unintentional emission of radio frequencies as much as possible. Digital circuits should also be packaged in conductive enclosures when pos sible to minimize the digital signals from being radiated as electromagnetic interference to other devices, and to protect the device from external electro magnetic fields and static discharge.
High order harmonics from clock edges can be mitigated by the use of ferrite beads (small value inductors) that reduce the amplitude of the higher clock harmonics. Clocks should also be kept away from I/O signals and connectors to reduce the coupling of clock noise to wires and interconnects that can act as antennas, conducting and radiating clock harmonics as radio interference.
14. Manufacturing and Test Issues
Manufacturing of boards can be made simpler if the design implements a method that allows programming processors, memories, and PLDs while the components are mounted to the card. This facilitates manufacturing the boards prior to pro gramming the devices. This also facilitates loading test programs into the board to allow more effective tests to determine of the board is operating as intended.
Signals which control or enable outputs or programming signals that might need to be disabled and driven externally for test purposes should be isolated from a test point with a series resistor, allowing an external test or programming circuit to drive the signal without damaging the output device on the board.
The inclusion of easily probed test points also makes it easier to diagnose failures by making it easier to probe critical signals on the board.
B |
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APPENDIX B |
225 |
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References, Web Links,
and Other Sources
Since he number of information sources that may be of interest is too great to include a comprehensive list—and many links to the information become obsolete—the sources noted in this chapter are just the starting points for more detailed information. Some of the books listed here relate directly to this subject, and others are some of my personal favorites, as they contain information which I make reference to regularly.
An important thing to keep in mind for any source of information is who the source is and how they derive their income. Trade magazines are useful, and because they are free to qualified subscribers, they are very popular source of information. Unfortunately, they derive their income solely from their adver tisers, and most of the articles are written by advertisers and the magazine editors. As a result, they often portray a very biased view of what’s going on in the industry. Likewise, web sites and other advertiser supported information sources often have very slanted versions of reality. There are a few exceptions, such as magazines that are supported by subscriptions as well as advertising, that have articles written by those of us who are down in the trenches. They often provide a more accurate, though still biased, view of what’s really going on.
Books
The Art of Electronics, by Horowitz and Hill, also the accompanying Student Manual, by Hayes and Horowitz, to accompany the text. This is an all-time favorite tome that covers an incredibly wide range of topics in a very readable and useful way. The student guide provides a refreshing review of the practical side of electronics, and will be invaluable for those who need to learn more about electronics.
226EMBEDDED CONTROLLER
Hardware Design
The Circuit Designer’s Companion, by Tim Williams is a good reference for understanding the differences between ideal circuits you learn about in school, and the things that happen in the real world. Includes a lot of material on undesirable component behaviors that the manufacturers frequently gloss over if they deal with them at all.
High-Speed Digital Design, a Handbook of Black Magic, by Howard W. Johnson and Martin Graham, which in spite of it’s subtitle, is soundly based in math and scientific principles, and provides a clear description of what really hap pens in high-speed circuits. This is an excellent text to understand the design of reliable high-speed circuits, which often exhibit non-ideal characteristics.
The Microcontroller Idea Book, by Jan Axelson uses the 8051BASIC chip to illustrate a range of introductory embedded applications. Jan is an excellent writer, as well as thorough and practical, so you should probably just give in and go buy all of her books.
Serial Port Complete, by Jan Axelson covers use of the PC’s serial port and can be very useful when interfacing an embedded controller to a PC’s serial COM port.
Parallel Port Complete, by Jan Axelson covers use of the PC’s parallel port and can be very useful when interfacing an embedded controller to a PC’s parallel port.
Printed Circuits Handbook, by Clyde F. Coombs is the standard reference text covering the design and manufacture of printed circuit boards.
The Cartoon Guide to Physics, by Gonick and Huffman is a great introduction to physics and basic electronics, using humorous cartoons to illustrate basic principles without resorting to complex math.
A Whack On The Side Of The Head, by Roger von Oech, is a humorous and effective book describing how to learn to be innovative.
Web and FTP Sites
The sites listed below can be reached through links provided on the companion CD-ROM, but they can quickly become obsolete, so they are also on the book web site at www.hte.com/echdbook. In addition, the LLH Technology Publishing web site will carry updates and corrections to this book; be sure to visit them at www.LLH-Publishing.com.