80C186EC/80C188EC Microprocessor User's Manual
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80C186EC/80C188EC Microprocessor User’s Manual 80C186EC/80C188EC Microprocessor User’s Manual 1995 Information in this document is provided solely to enable use of Intel products. Intel assumes no liability whatsoever, including infringement of any patent or copyright, for sale and use of Intel products except as provided in Intel’s Terms and Conditions of Sale for such products. Intel Corporation makes no warranty for the use of its products and assumes no responsibility for any errors which may appear in this document nor does it make a commitment to update the information contained herein. Intel retains the right to make changes to these specifications at any time, without notice. Contact your local Intel sales office or your distributor to obtain the latest specifications before placing your product order. MDS is an ordering code only and is not used as a product name or trademark of Intel Corporation. Intel Corporation and Intel's FASTPATH are not affiliated with Kinetics, a division of Excelan, Inc. or its FASTPATH trademark or products. *Other brands and names are the property of their respective owners. Additional copies of this document or other Intel literature may be obtained from: Intel Corporation Literature Sales P.O. Box 7641 Mt. Prospect, IL 60056-7641 or call 1-800-879-4683 © INTEL CORPORATION, 1995 CONTENTS CHAPTER 1 INTRODUCTION 1.1 HOW TO USE THIS MANUAL....................................................................................... 1-2 1.2 RELATED DOCUMENTS .............................................................................................. 1-3 1.3 ELECTRONIC SUPPORT SYSTEMS ........................................................................... 1-4 1.3.1 FaxBack Service .......................................................................................................1-4 1.3.2 Bulletin Board System (BBS) ....................................................................................1-5 1.3.2.1 How to Find ApBUILDER Software and Hypertext Documents on the BBS ...1-6 1.3.3 CompuServe Forums ................................................................................................1-6 1.3.4 World Wide Web .......................................................................................................1-6 1.4 TECHNICAL SUPPORT ................................................................................................ 1-6 1.5 PRODUCT LITERATURE.............................................................................................. 1-7 1.6 TRAINING CLASSES .................................................................................................... 1-7 CHAPTER 2 OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE 2.1 ARCHITECTURAL OVERVIEW .................................................................................... 2-1 2.1.1 Execution Unit ...........................................................................................................2-2 2.1.2 Bus Interface Unit .....................................................................................................2-3 2.1.3 General Registers .....................................................................................................2-4 2.1.4 Segment Registers ...................................................................................................2-5 2.1.5 Instruction Pointer .....................................................................................................2-6 2.1.6 Flags .........................................................................................................................2-7 2.1.7 Memory Segmentation ..............................................................................................2-8 2.1.8 Logical Addresses ...................................................................................................2-10 2.1.9 Dynamically Relocatable Code ...............................................................................2-13 2.1.10 Stack Implementation .............................................................................................2-15 2.1.11 Reserved Memory and I/O Space ...........................................................................2-15 2.2 SOFTWARE OVERVIEW ............................................................................................ 2-17 2.2.1 Instruction Set .........................................................................................................2-17 2.2.1.1 Data Transfer Instructions .............................................................................2-18 2.2.1.2 Arithmetic Instructions ...................................................................................2-19 2.2.1.3 Bit Manipulation Instructions .........................................................................2-21 2.2.1.4 String Instructions ..........................................................................................2-22 2.2.1.5 Program Transfer Instructions .......................................................................2-23 2.2.1.6 Processor Control Instructions ......................................................................2-27 2.2.2 Addressing Modes ..................................................................................................2-27 2.2.2.1 Register and Immediate Operand Addressing Modes ...................................2-27 2.2.2.2 Memory Addressing Modes ...........................................................................2-28 2.2.2.3 I/O Port Addressing .......................................................................................2-36 2.2.2.4 Data Types Used in the 80C186 Modular Core Family .................................2-37 iii CONTENTS 2.3 INTERRUPTS AND EXCEPTION HANDLING ............................................................ 2-39 2.3.1 Interrupt/Exception Processing ...............................................................................2-39 2.3.1.1 Non-Maskable Interrupts ...............................................................................2-42 2.3.1.2 Maskable Interrupts .......................................................................................2-42 2.3.1.3 Exceptions .....................................................................................................2-42 2.3.2 Software Interrupts ..................................................................................................2-44 2.3.3 Interrupt Latency .....................................................................................................2-44 2.3.4 Interrupt Response Time ........................................................................................2-45 2.3.5 Interrupt and Exception Priority ...............................................................................2-46 CHAPTER 3 BUS INTERFACE UNIT 3.1 MULTIPLEXED ADDRESS AND DATA BUS................................................................ 3-1 3.2 ADDRESS AND DATA BUS CONCEPTS..................................................................... 3-1 3.2.1 16-Bit Data Bus .........................................................................................................3-1 3.2.2 8-Bit Data Bus ...........................................................................................................3-5 3.3 MEMORY AND I/O INTERFACES................................................................................. 3-6 3.3.1 16-Bit Bus Memory and I/O Requirements ...............................................................3-7 3.3.2 8-Bit Bus Memory and I/O Requirements .................................................................3-7 3.4 BUS CYCLE OPERATION ............................................................................................ 3-7 3.4.1 Address/Status Phase ............................................................................................3-10 3.4.2 Data Phase .............................................................................................................3-13 3.4.3 Wait States ..............................................................................................................3-13 3.4.4 Idle States ...............................................................................................................3-18 3.5 BUS CYCLES .............................................................................................................. 3-20 3.5.1 Read Bus Cycles ....................................................................................................3-20 3.5.1.1 Refresh Bus Cycles .......................................................................................3-22 3.5.2 Write Bus Cycles .....................................................................................................3-23 3.5.3 Interrupt Acknowledge Bus Cycle ...........................................................................3-26 3.5.3.1 System Design Considerations .....................................................................3-28 3.5.4 HALT Bus Cycle ......................................................................................................3-29 3.5.5 Temporarily Exiting the HALT Bus State .................................................................3-32 3.5.6 Exiting HALT ...........................................................................................................3-34 3.6 SYSTEM DESIGN ALTERNATIVES ........................................................................... 3-36 3.6.1 Buffering the Data Bus ............................................................................................3-37