Edge and Level Triggering | Intel 80C186XL, 80C188XL manual

INTERRUPT CONTROL UNIT

8.3.6Edge and Level Triggering

The external interrupts (INT3:0) can be programmed for either edge or level triggering (see “In- terrupt Control Registers” on page 8-12). Both types of triggering are active high. An edge-trig- gered interrupt is generated by a zero-to-one transition on an external interrupt pin. The pin must remain high until after the CPU acknowledges the interrupt, then must go low to reset the edge- detection circuitry. (See the current data sheet for timing requirements.) The edge-detection cir- cuitry must be reset to enable further interrupts to occur.

A level-triggered interrupt is generated by a valid logic one on the external interrupt pin. The pin must remain high until after the CPU acknowledges the interrupt. Unlike edge-triggered inter- rupts, level-triggered interrupts will continue to occur if the pin remains high. A level-triggered external interrupt pin must go low before the EOI command to prevent another interrupt.

NOTE

When external 8259As are cascaded into the Interrupt Control Unit, INT0 and INT1 must be programmed for level-triggered interrupts.

8.3.7Additional Latency and Response Time

The Interrupt Control Unit adds 5 clocks to the interrupt latency of the CPU. Cascade mode adds 13 clocks to the interrupt response time because the CPU must run the interrupt acknowledge bus cycles. (See Figure 8-3 on page 8-11 and Figure 2-27 on page 2-46.)

8-10

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Intel 80C186XL, 80C188XL user manual Edge and Level Triggering, Additional Latency and Response Time

Contents

80C186XL/80C188XL Microprocessor User’s Manual 80C186XL/80C188XL Microprocessor User’s Manual Intel Corporation Contents Contents Power Management Setting the PCB Base LocationClock Generation LCS Chapter Refresh Control Unit Programming the Interrupt Control Unit Functional Overview Programming the TIMER/COUNTER UnitFunctional Overview Chapter Math Coprocessing Chapter Once Mode Figures UCS Reset Configuration Interrupt Control Register for Noncascadable External Pins 10-9 Tables Flag Bit Functions Example Examples Introduction Page Chapter Introduction Feature 80C186XL 80C186EA 80C186EB 80C186EC HOW to USE this ManualComparison of 80C186 Modular Core Family Products Related Documents and Software Related DocumentsDocument/Software Title Order No Electronic Support Systems FaxBack Service Bulletin Board System BBS World Wide Web CompuServe ForumsTechnical Support Training Classes Product LiteraturePage Overview 80C186 Family Architecture Page Architectural Overview Chapter Overview of the 80C186 Family Architecture Execution Unit Simplified Functional Block Diagram of the 80C186 Family CPU Physical Address Generation Bus Interface Unit General Registers General Registers Implicit Use of General Registers Segment RegistersOperations Segment Registers Instruction Pointer Flags Memory Segmentation Register Mnemonic Register NamePSW Flags Register Function Segment Locations in Physical Memory Logical Addresses Fffffh Data DS Code CS Stack SS Extra ES 2BFH 2BEH 2BDH 2BCH 2BBH 2BAH Dynamically Relocatable Code Type of Memory Reference Default Alternate OffsetLogical Address Sources Segment Code Data Before After Relocation Code SegmentSegment Data Extra Reserved Memory and I/O Space Stack Implementation 10. Stack Operation Instruction Set Software Overview General-Purpose Data Transfer InstructionsInput/Output Sahf 7 6 5 4 3 2 1 Lahf S Z U a U P U CPushf Popf U U O D I T S Z U a U P U C 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Subtraction AdditionMultiplication Division Bit Manipulation Instructions Arithmetic Interpretation of 8-Bit NumbersHex Bit Pattern Unsigned Signed Unpacked Packed Binary Shifts String Instructions Program Transfer Instructions String Instruction Register and Flag UseCX AL/AX Overview of the 80C186 Family Architecture Unconditional Transfers Conditional TransfersIteration Control Interrupts Mnemonic Condition Tested Jump if… 10. Interpretation of Conditional Transfers Processor Control Instructions Addressing Modes11. Processor Control Instructions Register and Immediate Operand Addressing Modes Memory Addressing Modes BIU 0000 Physical Addr 13. Direct Addressing Opcode Mod R/M Displacement 15. Based Addressing 14. Register Indirect Addressing Rate Base Vac Displacement High Address Rate AgeBase Register Register Dept Div Employee Age 17. Indexed Addressing 18. Accessing an Array with Indexed Addressing 19. Based Index Addressing 20. Accessing a Stacked Array with Based Index Addressing Opcode Source EA Destination EA 12. Supported Data Types Data Types Used in the 80C186 Modular Core FamilyType Description BCD 23 C186 Modular Core Family Supported Data Types Interrupt/Exception Processing Interrupts and Exception Handling 3FC 3FE Overview of the 80C186 Family Architecture Stack Interrupt Enable BitPSW Trap Flag Exceptions Maskable Interrupts Invalid Opcode Type Interrupt Latency Software Interrupts Clocks Interrupt Response TimeTotal Interrupt and Exception Priority NMI Execute Divide Service RoutineIret 29. Simultaneous NMI and Single Step Interrupts Trap Flag = ??? 30. Simultaneous NMI, Single Step and Maskable Interrupt Interrupt Enable Bit IE = Trap Flag TF =Page Bus Interface Unit Page Address and Data BUS Concepts Multiplexed Address and Data BUS1 16-Bit Data Bus MByte KBytes Physical Implementation Address Space forFffff Ffffe Ffffd Ffffc A190 D70 A191 D158 A191 D158 BHE High Even Byte TransferOdd Byte Transfer D70 A0 Low A191 D158 BHE High Bit Data Bus Even Word Transfers A191 D158 BHE Low D70 A0 Low A191 D158 BHE Low First Bus CycleSecond Bus Cycle D70 A0 High A191 D158 BHE Low Bit Data Bus Word Transfers Memory and I/O Interfaces 2 8-Bit Bus Memory and I/O Requirements 1 16-Bit Bus Memory and I/O RequirementsBUS Cycle Operation Low Phase High Phase PhaseClkout ALE S20 Valid Status AD150 Address Data Request Pending Bus ReadyHold Deasserted RES# Address/Status Phase Address Status Phase Or TW Or TI Data PhaseOr TI Clkout S20 A1916 ALE STB STB Wait States Data Phase Clkout RD/ WR Or TW Or TIAD150 Valid Write Data Read Read Data S20 Ardy Clkout Srdy ReadyBUS Ready CS1 CS2 CS3 CS4 ALE Clkout Clock 16. Generating a Normally Ready Bus Signal Idle States Clkout Ardy Srdy 18. Normally Ready System Timings Read Bus Cycles BUS CyclesRead Bus Cycle Types Read Cycle Critical Timing Parameters Rfsh A158A150 DT/R DEN AD70 O0-7 UCS27C256 LA151 AD158 Write Bus Cycle Types A158 A150Status Bits Bus Cycle Type LA0 BHE LA151A014 O18 CS1 AD70 AD158 LCS Write Cycle Critical Timing Parameters Interrupt Acknowledge Bus Cycle Lock DT/R DEN INTA0 INTA1BHE RD, WR INTA0 Inta INT0 IR0 IR7 PCS0 LA1 Processor 82C59ASystem Design Considerations Halt Bus Cycle 011 AD150 AD70 A158 A1916 Pins Pin StateRfsh = BHE Clkout Hold Hlda Temporarily Exiting the Halt Bus StateAD150 AD70 A158 A1916 Control BHE Rfsh S20 AD150 AD70 A158 A1916 T3 TI TI TI TI T4 T1 T2 T3AD70 A158 RFSH=1 System Design Alternatives NMI/INTx Clkout RD,WR DT/R DEN Buffering the Data Bus DT/ R DeviceCPU Local Bus Buffered Bus Buffer Buffered Data Bus AD70 MCS0Buffer Local Data Bus Synchronizing Software and Hardware Events Using a Locked Bus Queue Status Signal Decoding Using the Queue Status SignalsQueue Status No queue operation occurred Entering Bus Hold MULTI-MASTER BUS System Designs Float Signal Hold ConditionRD, W R Float BHE , S20 Lock Refresh Operation During a Bus Hold BHE, S20 Clkout Hold Hlda DEN RD, WRDT/R Lock Latched Hlda Hlda Reset Hold PRE CLRExiting Hold DT/R, S20 A1916, Lock DEN RD, WR, BHEBUS Cycle Priorities BUS Interface Unit Page Peripheral Control Block Page PCB Relocation Register Peripheral Control Registers Register Name PCB Relocation Register Register Mnemonic Bit Bit Name Reset Function Mnemonic StateRelreg Peripheral Control Block Ready Signals and Wait States Accessing the Peripheral Control BlockReserved Locations Bus Cycles Word reads Bus Operation Accessing the Peripheral Control Registers Setting the PCB Base LocationAccessing Reserved Locations Writing the PCB Relocation Register Considerations for the 80C187 Math Coprocessor Interface Page Clock Generation Power Management Page RES Clock GenerationCrystal Oscillator Oscillator Operation = Inverter Output Z 90˚ 180˚ Crystal Connections to Microprocessor Values µH Third-Overtone Crystal Inductor L1 Selecting Crystals Reset and Clock Synchronization Using an External OscillatorOutput from the Clock Generator 1µf typical Typical Ct = V 1 e Cold Reset Waveform Clkout PCS60,NCS Power Management Clkout ResetRES Resync Entering Power-Save Mode Power-Save Mode Enables and sets clock division factor Power Save RegisterRegister Name Register Mnemonic Register Function Pwrsav Example Power-Save Initialization Code 10. Power-Save Clock Transition Leaving Power-Save Mode Syntax Chip-Select Unit Page Common Methods for Generating CHIP-SELECTS CHIP-SELECT Unit Features and Benefits CHIP-SELECT Unit Functional Overview Chip-Selects Using Addresses Directly Simple Decoder27C256 74AC138 MCS2 MCS3MCS1 PCS1 MCS30, LCS A1916 UCS, PC S60 Srdy Ardy UCS 1AddressData Active For Top 1 KByte Memory Map 1MB Initialization Sequence ProgrammingChip-Select Unit Registers Control Register Alternate Register Umcs UCS Control RegisterControls the operation Chip-select Lmcs LCS Control Register Mmcs MCS Control RegisterControls the operation Chip-selects MCS Pacs PCS Control RegisterPCS Mpcs Register NameMCS and PCS Alternate Control RegisterX S UCS Active Range Programming the Active RangesUCS Block Size and Starting Address Umcs Field Block Size Starting Address U1710 LCS Active Range LCS Active RangeMCS Active Range Lmcs Field Block Size Ending Address U1710 Block Size Mmcs Start Address Kbytes Restrictions MCS Block Size and Start Address Restrictions PCS Active Range Bus Wait State and Ready Control Wait State Ready R2 Control Bit Wait Wait State Value R10 State CounterOverlapping Chip-Selects Programming Considerations Memory or I/O Bus Cycle Decoding CHIP-SELECTS and BUS Hold Example 1 Typical System ConfigurationExamples 13. Typical System MOD186XREF Name CSUEXAMPLE1 Example 6-1. Initializing the Chip-Select Unit Drambase EQU Place memory variables here Refresh Control Unit Page CLR REQ CPU Refresh Control Unit Capabilities Role of the Refresh Control UnitRefresh Control Unit Operation Refresh Control Unit Operation Flow Chart Refresh Address Formation Refresh Addresses Guidelines for Designing Dram Controllers Refresh BUS CyclesIdentification of Refresh Bus Cycles Data Bus Width Muxed Row Column Address S20 T3/TW ClkoutRAS CAS Calculating the Refresh Interval Programming the Refresh Control UnitRefresh Control Unit Registers Rfbase Register NameRefresh Base Address RegisterRegister FunctionDetermines upper 7 bits of refresh address Refresh Base Address Register Register Function Sets refresh rate Rftime Rfcon Refresh Control RegisterControls Refresh Unit operation Programming Example Example 7-1. Initializing the Refresh Control Unit Refresh Operation and BUS Hold RD, WR BHE, S2 DT / R A1916 Clkout Hold Hlda DENPage Interrupt Control Unit Page Functional Overview Chapter Interrupt Control Unit Timer 0 Timer 1 Timer Master ModeGeneric Functions in Master Mode DMA Interrupt Masking Default Interrupt PrioritiesInterrupt Priority Interrupt Name Relative Priority Interrupt Nesting Priority Resolution Functional Operation in Master ModeTypical Interrupt Sequence Priority Resolution Example Interrupts That Share a Single Source Cascading with External 8259As Inta INTA0 INT INT0INT INT1 Inta INTA1 Polling Interrupt Acknowledge SequenceFixed Interrupt Types Interrupt Name Interrupt Type Additional Latency and Response Time Edge and Level Triggering Inta Idle Read IP Inta IdleRead CS Idle Push Flags Push CS Push IP Programming the Interrupt Control Unit 2CH Interrupt Control Registers2AH MSK Interrupt Control Register for Internal Sources I2CON, I3CON Register NameInterrupt Control Register non-cascadable pinsLVL I0CON, I1CON Register NameInterrupt Control Register cascadable pinsSfnm CAS Register Name Interrupt Request Register Register Mnemonic Interrupt Request RegisterReqst Register Function Stores pending interrupt requests Imask Register Name Interrupt Mask Register Register MnemonicRegister Function Masks individual interrupt sources Priority Mask Register Priority Mask Register In-Service RegisterPrimsk Masks lower-priority interrupt sources Inserv In-Service RegisterIndicates which interrupt handlers are in process Poll and Poll Status Registers Poll Poll RegisterIreq Poll Status Register Read to check for pending interrupts when pollingPollsts End-of-Interrupt EOI Register End-of-Interrupt Register Used to issue an EOI commandEOI Interrupt Status Register Interrupt Status Register Slave ModeIntsts Dhlt IRQ INT VCC INT0 Inta 16. Interrupt Sources in Slave Mode Slave Mode Programming Master Mode Slave Mode PCB Offset Register Name Slave Mode Fixed Interrupt Type BitsInterrupt Vector Register Interrupt Control Unit Register Comparison Intvec Register NameInterrupt Vector Register Slave Mode only Used to issue the EOI command End-of-Interrupt Register in Slave Mode T1 T2 T3 T4 Interrupt Vectoring in Slave ModeInta INTA0 Select Lock CAS20 Slave Cascade Address From 8259A Inta Idle Read IP Read CS Push Flags Push CS Push IP Initializing the Interrupt Control Unit for Master Mode Priorities are used Page Timer/Counter Unit Page Chapter TIMER/COUNTER Unit Interrupt Latch Clock Timer Element Registers Output Latch T0IN T1IN T0OUT T1OUT Counter Element Multiplexing and Timer Input Synchronization Timers 0 and 1 Flow Chart From Timer/Counter Unit Output Modes Programming the TIMER/COUNTER Unit Defines Timer 0 and 1 operation Timer 0 and 1 Control RegistersT0CON, T1CON EXT RTGALT Cont Defines Timer 2 operation Timer 2 Control RegisterT2CON Maximum count. The MC bit must be cleared Register Function Contains the current timer count Register Name Timer Count Register Register MnemonicT0CNT, T1CNT, T2CNT C C Timer Maxcount Compare Registers Clock Sources Timer 0 and 1 Clock SourcesCounting Modes Clock Source Retriggering Timer Operation Timer RetriggeringPulsed and Variable Duty Cycle Output Enabling/Disabling Counters Timer Serviced Internal Count Value Maxcount TxOUT Pin Input Setup and Hold Timings Timer InterruptsTiming Synchronization and Maximum Frequency Timer/Counter Unit Application ExamplesReal-Time Clock Square-Wave Generator Intsts Example 9-1. Configuring a Real-Time Clock Out Dx, al Timer2interruptroutine proc far T1CON Example 9-2. Configuring a Square-Wave Generator Example 9-3. Configuring a Digital One-Shot Cmpb Page Direct Memory Access Unit Page DMA Transfer Chapter Direct Memory Access Unit Typical DMA Transfer Fetch Deposit DMA Requests Source and Destination PointersDMA Transfer Directions Byte and Word Transfers T1 or T2 or T3 or TW or T4 or External RequestsCycle DRQ Source Synchronization DRQ Case Fetch Cycle Deposit Cycle T1 T2 T3 T4 T1 T2 T3 T4 TI TI Timer 2-Initiated TransfersClkout DRQ Case Termination and Suspension of DMA Transfers DMA Transfer Counts DMA Cycles and the BIU DMA Unit InterruptsTwo-Channel DMA Unit DMA Channel Arbitration Two-Channel DMA Module Module Programming the DMA Unit SRCDMA Channel Parameters Register Mnemonic DxSRCH Register NameDMA Source Address Pointer HighDMA Xxxxh Register Mnemonic DxSRCL Register NameDMA Source Address Pointer LowS S a a DxDSTH Register NameDMA Destination Address Pointer HighContains the upper 4 bits of the DMA Destination pointer Register Mnemonic DxDSTL Register NameDMA Destination Address Pointer Low Dmem D I E N C C C N TDdec Dinc Idrq Synchronization Type Strt CHGWord Selecting Channel Synchronization Arming the DMA ChannelProgramming the Transfer Count Options Generating Interrupts on Terminal Count Setting the Relative Priority of a Channel Initializing the DMA Unit Suspension of DMA TransfersHardware Considerations and the DMA Unit DRQ Pin Timing Requirements DMA Transfer Rates DMA Latency DMA Unit Examples Generating a DMA Acknowledge MOV DS, AX Assume Dsdataseg Example 10-1. Initializing the DMA Unit 10-24 10-25 Example 10-2. Timed DMA Transfers 10-27 Page Math Coprocessing Page Availability of Math Coprocessing Overview of Math Coprocessing 11.3.1 80C187 Instruction Set 80C187 Math Coprocessor Real Transfers C187 Data Transfer InstructionsInteger Transfers Packed Decimal Transfers Other Operations C187 Arithmetic Instructions C187 Comparison Instructions Comparison InstructionsTranscendental Instructions C187 Transcendental Instructions C187 Constant Instructions Constant InstructionsC187 Processor Control Instructions Fldz FLD1 Fldpi FLDL2T FLDL2E FLDLG2 FLDLN2 Microprocessor and Coprocessor Operation 11.3.2 80C187 Data Types C187-Supported Data Types Modular Core 80C18780C186 Clocking the 80C187 Processor Bus Cycles Accessing the 80C187C187 I/O Port Assignments Address Read Definition Write Definition System Design Tips C187 Configuration with a Partially Buffered Bus Example Math Coprocessor Routines Exception Trapping C187 Exception Trapping via Processor Interrupt Pin 80C186 Modular Core Name Example80C187init Results Example 11-2. Floating Point Math Routine Using Fsincos Once Mode Page ENTERING/LEAVING Once Mode Chapter Once Mode Oscout RES UCS LCS 80C186 Instruction Set Additions Extensions Page Data Transfer Instructions 80C186 Instruction SET Additions High-Level Instructions String Instructions Figure A-1. Formal Definition of Enter Figure A-2. Variable Access in Nested Procedures Figure A-4. Stack Frame for Procedure a at Level BPM BPA BPB Leave 80C186 Instruction SET Enhancements Bound register, address Bit Manipulation Instructions Arithmetic InstructionsShift Instructions Rotate Instructions ROL destination, count Input Synchronization Page Figure B-1. Input Synchronization Circuit WHY Synchronizers are Required Asynchronous Pins Instruction Set Descriptions Page Variable Description Table C-1. Instruction Format Variables Operand Description Table C-2. Instruction Operands Table C-3. Flag Bit Functions Table C-4. Instruction Set AAS Ascii Adjust for SubtractionADC Add with Carry ADD dest, src ADDLogical Dest, src Call procedure-name Call ProcedureBound Detect Value Out of Range Clear Carry flag Convert Byte to WordClear Direction flag Complement Carry Flag Clear Interrupt-enable Flag Compare CMPCMP dest, src Compare String Decimal Adjust for Subtraction Decimal Adjust for AdditionConvert Word to Doubleword Decrement DEC When Source Operand is a Word Divide When Source Operand is a Byte Enter locals, levels Procedure EntryEscape Halt Integer Divide When Source Operand is a Byte Input Byte or Word When Source Operand is a Byte Integer Multiply When Source Operand is a ByteImul Accum, port Increment INCString INS dest-string, port INT interrupt-type Interrupt Interrupt Return Interrupt on OverflowJump on Above Jump on Not Below or Equal Jump on Not Below Jump on Above or EqualJump on Below Jump on Not Above or Equal Jump on Equal Jump on Zero Jump if CX ZeroJump on Greater Than Jump on Not Less Than or Equal Jump on Not Greater Than or Equal Name Description Operation Flags Affected Jump on Less ThanJump on Less Than or Equal Jump on Not Greater Than Jump on Not Zero Jump on Not EqualJump on Not Overflow Jump on Not Sign Jump on Parity Name Description Operation Flags Affected Jump on OverflowJump on Parity Equal Instruction Format LDS dest, src Load Pointer Using DSLoad Effective Address LEA dest, src LES dest, src Load Pointer Using ESLock the Bus Lods src-string Load String Byte or Word When Source Operand is a ByteLoop Loop While Equal Loop While Not Zero Loop While Not EqualMove Byte or Word MOV dest, src Move String Multiply When Source Operand is a ByteMovs dest-string, src-string MUL Logical Not When Source Operand is a Byte Negate When Source Operand is a ByteNEG Or dest,src Name Description Operation Flags Affected Logical orOutput OUT port, accumulator Outs port, srcstring Out StringPop Pop Flags Pop AllPush Push Flags Push All RCL dest, count Rotate Through Carry LeftRotate Through Carry Right RCR dest, count Repeat While Equal RepeatRepeat While Zero Repeat While Not Equal Return RETRET optional-pop-value Rotate Left ROR dest, count Rotate RightStore Register AH Into Flags Shift Arithmetic Left Shift Logical LeftShift Arithmetic Right Subtract With Borrow SBBSBB dest, src Scas dest-string Scan String When Source Operand is a Byte SHR dest, src Shift Logical RightSet Carry Flag Set Direction Flag Store Byte or Word String When Source Operand is a Byte Set Interrupt-enable FlagStos dest-string Subtract SUBSUB dest, src Test Exchange WaitXchg dest, src Xlat translate-table TranslateExclusive Or XOR dest, srcPage Instruction Set Opcodes and Clock Cycles Page EA Calculation Table D-1. Operand VariablesMod Effect on EA Calculation Reg Bit w=1 Bit w=0 Function Format Clocks Table D-2. Instruction Set Summary Arithmetic Instructions Arithmetic Instructions BIT Manipulation Instructions String Manipulation Instructions JB/JNAE = LOOPNZ/LOOPNE = Processor Control Instructions Table D-3. Machine Instruction Decoding Guide Instruction SET Opcodes and Clock Cycles Instruction SET Opcodes and Clock Cycles Instruction SET Opcodes and Clock Cycles Instruction SET Opcodes and Clock Cycles AX,CX Instruction SET Opcodes and Clock Cycles Instruction SET Opcodes and Clock Cycles Instruction SET Opcodes and Clock Cycles AL,DX Instruction SET Opcodes and Clock Cycles Table D-4. Mnemonic Encoding Matrix Left Half Table D-4. Mnemonic Encoding Matrix Right Half Abbr Definition Table D-5. Abbreviations for Mnemonic Encoding Matrix Index Page Index Index-2 Index-3 Index-4 Index-5 Index-6 Index-7 Index-8