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10-1

CHAPTER 10

DIRECT MEMORY ACCESS UNIT

In many applications, large blocks of data must be transferred between memory and I/O space. A
disk drive, for example, usually reads and writes data in blocks that may be thousands of bytes
long. If the CPU were required to handle each byte of the transfer, the main tasks would suffer a
severe performance penalty. Even if the data transfers were interrupt driven, the overhead for
transferring control to the interrupt handler would still decrease system throughput.

Direct Memory Access, or DMA, allows data to be transferred between memory and peripherals
without the intervention of the CPU. Systems that use DMA have a special device, known as
the DMA controller, that takes control of the system bus and performs the transfer between mem-
ory and the peripheral device. When the DMA controller receives a request for a transfer from a
peripheral, it signals the CPU that it needs control of the system bus. The CPU then releases con-
trol of the bus and the DMA controller performs the transfer. In many cases, the CPU releases the
bus and continues to execute instructions from the prefetch queue. If the DMA transfers are rel-
atively infrequent, there is no degradation of software performance; the DMA transfer is trans-
parent to the CPU.

The DMA Unit has two channels. Each channel can accept DMA requests from one of three
sources: an external request pin, the Timer/Counter Unit or direct programming. Data can be
transferred between any combination of memory and I/O space. The DMA Unit can access the
entire memory and I/O space in either byte or word increments.

10.1   FUNCTIONAL OVERVIEW

The DMA Unit consists of two channels that are functionally identical. The following discussion
is hierarchical, beginning with an overview of a single channel and ending with a description of
the two-channel unit.

10.1.1   The DMA Transfer

A DMA transfer begins with a request. The requesting device may either have data to transmit (a
source request) or it may require data (a destination request). Alternatively, transfers may be ini-
tiated by the system software without an external request.

Содержание 80C186EA

Страница 1: ...80C186EA 80C188EA Microprocessor User s Manual...

Страница 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...

Страница 3: ...s 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...

Страница 4: ...t 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...

Страница 5: ...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 Cycl...

Страница 6: ...MANAGEMENT 5 1 CLOCK GENERATION 5 1 5 1 1 Crystal Oscillator 5 1 5 1 1 1 Oscillator Operation 5 2 5 1 1 2 Selecting Crystals 5 5 5 1 2 Using an External Oscillator 5 6 5 1 3 Output from the Clock Gen...

Страница 7: ...4 6 Programming Considerations 6 17 6 5 CHIP SELECTS AND BUS HOLD 6 18 6 6 EXAMPLES 6 18 6 6 1 Example 1 Typical System Configuration 6 18 CHAPTER 7 REFRESH CONTROL UNIT 7 1 THE ROLE OF THE REFRESH C...

Страница 8: ...Time 8 10 8 4 PROGRAMMING THE INTERRUPT CONTROL UNIT 8 11 8 4 1 Interrupt Control Registers 8 12 8 4 2 Interrupt Request Register 8 16 8 4 3 Interrupt Mask Register 8 16 8 4 4 Priority Mask Register...

Страница 9: ...onization 10 5 10 1 5 Internal Requests 10 6 10 1 5 1 Timer 2 Initiated Transfers 10 6 10 1 5 2 Unsynchronized Transfers 10 6 10 1 6 DMA Transfer Counts 10 7 10 1 7 Termination and Suspension of DMA T...

Страница 10: ...ctions 11 3 11 3 1 3 Comparison Instructions 11 5 11 3 1 4 Transcendental Instructions 11 5 11 3 1 5 Constant Instructions 11 6 11 3 1 6 Processor Control Instructions 11 6 11 3 2 80C187 Data Types 11...

Страница 11: ...3 1 Shift Instructions A 9 A 2 3 2 Rotate Instructions A 10 APPENDIX B INPUT SYNCHRONIZATION B 1 WHY SYNCHRONIZERS ARE REQUIRED B 1 B 2 ASYNCHRONOUS PINS B 2 APPENDIX C INSTRUCTION SET DESCRIPTIONS AP...

Страница 12: ...sed Index Addressing 2 35 2 21 String Operand 2 36 2 22 I O Port Addressing 2 36 2 23 80C186 Modular Core Family Supported Data Types 2 38 2 24 Interrupt Control Unit 2 39 2 25 Interrupt Vector Table...

Страница 13: ...s 3 36 3 32 Buffered AD Bus System 3 37 3 33 Qualifying DEN with Chip Selects 3 38 3 34 Queue Status Timing 3 41 3 35 Timing Sequence Entering HOLD 3 42 3 36 Refresh Request During HOLD 3 44 3 37 Latc...

Страница 14: ...8 8 8 3 Interrupt Control Unit Latency and Response Time 8 11 8 4 Interrupt Control Register for Internal Sources 8 13 8 5 Interrupt Control Register for Noncascadable External Pins 8 14 8 6 Interrupt...

Страница 15: ...r Bits 10 13 10 10 DMA Destination Pointer Low Order Bits 10 14 10 11 DMA Control Register 10 15 10 12 Transfer Count Register 10 19 11 1 80C187 Supported Data Types 11 8 11 2 80C186 Modular Core Fami...

Страница 16: ...Pin States 3 29 3 7 Queue Status Signal Decoding 3 40 3 8 Signal Condition Entering HOLD 3 42 4 1 Peripheral Control Block 4 3 5 1 Suggested Values for Inductor L1 in Third Overtone Oscillator Circuit...

Страница 17: ...11 10 C 1 Instruction Format Variables C 1 C 2 Instruction Operands C 2 C 3 Flag Bit Functions C 3 C 4 Instruction Set C 4 D 1 Operand Variables D 1 D 2 Instruction Set Summary D 2 D 3 Machine Instru...

Страница 18: ...7 1 Initializing the Refresh Control Unit 7 11 8 1 Initializing the Interrupt Control Unit for Master Mode 8 31 9 1 Configuring a Real Time Clock 9 18 9 2 Configuring a Square Wave Generator 9 21 9 3...

Страница 19: ......

Страница 20: ...1 Introduction...

Страница 21: ......

Страница 22: ...run at twice the clock rate of the NMOS 80186 while consuming less than one fourth the power The 80186 family took another major step in 1990 with the introduction of the 80C186EB family The 80C186EB...

Страница 23: ...EB C188EB 80C186EC C188EC and 80C186XL C188XL 80C186 Modular Core Without the word family this phrase refers only to the 16 bit bus mem bers of the 80C186 Modular Core Family 80C188 Modular Core This...

Страница 24: ...6 80C188 to the 80C186XL 80C188XL refer to FaxBack Document No 2132 Table 1 2 Related Documents and Software Document Software Title Document Order No Embedded Microprocessors includes 186 family data...

Страница 25: ...chine Each document has an order number and is listed in a subject catalog The first time you use Fax Back you should order the appropriate subject catalogs to get a complete list of document order nu...

Страница 26: ...s also available from FaxBack catalog number 6 see page 1 4 for phone num bers and a description of the FaxBack service 1 800 897 2536 U S and Canada only Any customer with a modem and computer can ac...

Страница 27: ...ion about CompuServe access and service fees call CompuServe at 1 800 848 8199 U S or 614 529 1340 outside the U S 1 3 4 World Wide Web We offer a variety of information through the World Wide Web htt...

Страница 28: ...2 Overview of the 80C186 Family Architecture...

Страница 29: ......

Страница 30: ...ion Unit requires another opcode byte it takes the byte out of the prefetch queue The two units can operate independently of one another and are able under most circumstances to overlap instruction fe...

Страница 31: ...Unit maintains the CPU status and control flags and manipulates the general reg isters and instruction operands All registers and data paths in the Execution Unit are 16 bits wide for fast internal t...

Страница 32: ...2 Bus Interface Unit The 80C186 Modular Core and 80C188 Modular Core Bus Interface Units are functionally iden tical They are implemented differently to match the structure and performance characteris...

Страница 33: ...C186 Modular Core family CPU has eight 16 bit general registers see Figure 2 3 The general registers are subdivided into two sets of four registers These sets are the data registers also called the H...

Страница 34: ...egment registers contain the base addresses starting locations of these memory segments see Figure 2 4 The CS register points to the current code segment which contains instructions to be fetched The...

Страница 35: ...Pointer but it can change be saved or be restored as a result of program execution For example if the Instruction Pointer is saved on the stack it is first automatically adjusted to point to the next...

Страница 36: ...terrupt in this situation If the Sign Flag SF is set the high order bit of the result is a 1 Since negative binary numbers are represented in standard two s complement notation SF indicates the sign o...

Страница 37: ...egment is composed of contiguous memory locations Segments are independent and sep arately addressable Software assigns every segment a base address starting location in memory space All segments begi...

Страница 38: ...0 If TF is set the processor enters single step mode SF Sign Flag 0 If SF is set the high order bit of the result of an operation is 1 indicating it is negative ZF Zero Flag 0 If ZF is set the result...

Страница 39: ...tween the CPU and memory use physical addresses Programs deal with logical rather than physical addresses Program code can be developed with out prior knowledge of where the code will be located in me...

Страница 40: ...of a memory location can come from different sources depending on the type of reference that is being made see Table 2 2 Segment registers always hold the segment base addresses The Bus Interface Uni...

Страница 41: ...2 12 Figure 2 8 Logical and Physical Address Physical Address Segment Base Logical Addresses 2C4H 2C3H 2C2H 2C1H 2C0H 2BFH 2BEH 2BDH 2BCH 2BBH 2BAH 2B9H 2B8H 2B7H 2B6H 2B5H 2B4H 2B3H 2B2H 2B1H 2B0H S...

Страница 42: ...ically adjust the SI and DI registers as they process the strings one byte or word at a time When an instruction designates the Base Pointer BP register as a base register the variable is assumed to r...

Страница 43: ...ide the current code segment All program offsets must be relative to the segment registers This allows the program to be moved anywhere in memory pro vided that the segment registers are updated to po...

Страница 44: ...ck see Figure 2 10 by first decrementing the SP register by 2 and then writing the data word An element is popped off the stack by copying it from the top of the stack and then incrementing the SP reg...

Страница 45: ...ck Bottom of stack POP AX POP BX TOS SS SP BB AA 10 50 1060 1062 105E 105B 105A 1058 1056 1054 1052 1050 22 00 44 66 88 AA 34 45 89 CD 33 11 55 77 99 BB 12 67 AB EF 12 34 1060 1062 105E 105B 105A 1058...

Страница 46: ...ved into and out of reg isters This saves instructions registers and execution time in assembly language programs In high level languages where most variables are memory based compilers can produce fa...

Страница 47: ...ing segment registers are also included in this group Figure 2 11 shows the flag storage formats The address object instructions manipulate the addresses of variables in stead of the values of the var...

Страница 48: ...ed binary Signed binary integers Unsigned packed decimal Unsigned unpacked decimal A1014 0A U Undefined Value is indeterminate O Overflow Flag D Direction Flag I Interrupt Enable Flag T Trap Flag S Si...

Страница 49: ...s and adjusts status flags accordingly Table 2 4 Arithmetic Instructions Addition ADD Add byte or word ADC Add byte or word with carry INC Increment byte or word by 1 AAA ASCII adjust for addition DAA...

Страница 50: ...value or as a variable in the CL register This allows the shift count to be a supplied at execution time Arithmetic shifts can be used to multiply and divide bi nary numbers by powers of two Logical s...

Страница 51: ...are loop The repetitions can be termi nated by a variety of conditions Repeated operations can be interrupted and resumed String instructions operate similarly in many respects see Table 2 8 A string...

Страница 52: ...nstruction Pointer register points to the memory location of the next instruction to be fetched In most operating conditions the next instruction will already have been fetched and will be waiting in...

Страница 53: ...is can be a problem when the CALL and RET instructions are in separately assembled programs The JMP instruction does not push any information onto the stack A JMP instruction can be NEAR or FAR Condit...

Страница 54: ...E Jump if less not greater nor equal JLE JNG Jump if less or equal not greater JNC Jump if not carry JNE JNZ Jump if not equal not zero JNO Jump if not overflow JNP JPO Jump if not parity parity odd J...

Страница 55: ...s in software or with an NMI Non Maskable Interrupt Table 2 10 Interpretation of Conditional Transfers Mnemonic Condition Tested Jump if JA JNBE CF or ZF 0 above not below nor equal JAE JNB CF 0 above...

Страница 56: ...f the instruction set The following para graphs briefly describe register and immediate modes of operand addressing A detailed descrip tion of the memory and I O addressing modes is also provided 2 2...

Страница 57: ...ter producing a 20 bit physical address One or more bus cycles are then run to access the operand The offset that the Execution Unit calculates for memory operand is called the operand s Effec tive Ad...

Страница 58: ...he position of the operand s name a variable or label in the program The programmer can modify this value or explicitly specify the displacement A1015 0A CS 0000 0000 0000 0000 SS DS ES Assumed Unless...

Страница 59: ...the displacement of the instruction Pro grammers typically use direct addressing to access scalar variables With register indirect addressing the effective address of a memory operand can be taken di...

Страница 60: ...ures that may be located in different places in memory see Figure 2 16 A base register can be pointed at the structure Elements of the structure can then be addressed by their displacements Different...

Страница 61: ...in an array see Figure 2 18 The displacement locates the beginning of the array and the value of the index register selects one element If the index register contains 0000H the processor selects the...

Страница 62: ...gure 2 18 Accessing an Array with Indexed Addressing EA DI SI Opcode Mod R M Displacement or A1020 0A Displacement EA High Address Index Register 14 Array 8 Array 7 Array 6 Array 5 Array 4 Array 3 Arr...

Страница 63: ...r can be used to access individual array elements Arrays contained in structures and matrices two dimensional arrays can also be accessed with based indexed addressing String instructions do not use n...

Страница 64: ...with Based Index Addressing Displacement EA High Address Index Register 6 12 Base Register Displacement EA Index Register 6 Base Register Array 6 Array 5 Array 4 Array 3 Array 2 Array 1 Array 0 Parm 2...

Страница 65: ...ber is an 8 bit immediate operand This allows fixed ac cess to ports numbered 0 to 255 Indirect I O port addressing is similar to register indirect address ing of memory operands The DX register conta...

Страница 66: ...inal An unsigned 8 or 16 bit binary numeric value unsigned byte or word BCD A byte unpacked representation of a single decimal digit 0 9 ASCII A byte representation of alphanumeric and control charact...

Страница 67: ...31 1 0 0 15 16 2 3 31 32 4 5 6 7 47 48 63 7 0 n 7 0 n 0 79 9 8 7 6 5 4 3 2 1 0 Most Significant Digit Least Significant Digit Byte Word n Byte Word 1 Byte Word 0 1 Signed Byte Signed Quad Word Unsigne...

Страница 68: ...ne maskable interrupt request see Figure 2 24 This discussion covers only those areas of interrupts and exceptions that are common to the 80C186 Modular Core family The Interrupt Control Unit is proli...

Страница 69: ...es 3FE 3FC 82 80 7E 7C 52 50 4E 4C 4A 48 46 44 42 40 3E 3C 3A 38 36 34 32 30 CS IP CS IP CS IP CS IP CS IP CS IP CS IP CS IP CS IP CS IP CS IP CS IP Type 11 DMA1 2E 2C 2A 28 26 24 22 20 1E 1C 1A 18 16...

Страница 70: ...rrupt service routine The programmer must save usually by pushing onto the stack all registers used in the interrupt service routine otherwise their contents will be lost To allow nesting of maskable...

Страница 71: ...Latency on page 2 45 The CPU au tomatically generates a type 2 interrupt vector The NMI input is asynchronous Setup and hold times are given only to guarantee recognition on a specific clock edge To b...

Страница 72: ...n that caused the exception can be restarted Faults are detected and ser viced before the faulting instruction can be executed The return address pushed onto the stack in the interrupt processing inst...

Страница 73: ...Relocation Register see Chapter 4 Peripheral Control Block When a floating point instruction is executed with the Escape Trap bit set the Escape Opcode fault occurs and the Escape Opcode service routi...

Страница 74: ...C186 Modular Core family mem ber and a zero wait state external bus The execution time for an 80C188 Modular Core family member may be longer depending on the queue This is one factor in determining i...

Страница 75: ...response time for the interrupts that supply their type Note that an on chip bus master such as the DRAM Refresh Unit can make use of idle bus cycles This can increase interrupt response time Figure...

Страница 76: ...the maskable interrupt However a pending NMI can interrupt the CPU at any valid instruction boundary Therefore NMI can interrupt an excep tion service routine If an exception and NMI occur simultaneou...

Страница 77: ...The maskable interrupt is serviced from within the single step service routine and that interrupt ser vice routine is not single stepped To prevent single stepping before an NMI the single step ser v...

Страница 78: ...Push PSW CS IP Fetch Single Step Vector IRET Execute Single Step Service Routine Execute Single Step Service Routine Push PSW CS IP Fetch NMI Vector Interrupt Enable Bit IE 1 Trap Flag TF 1 Interrupt...

Страница 79: ......

Страница 80: ...3 Bus Interface Unit...

Страница 81: ......

Страница 82: ...provided within the memory and I O devices can directly connect to the address data bus or local bus The local bus can be demultiplexed with a single set of address latches to provide non multiplexed...

Страница 83: ...o access even addressed 16 bit words two consecutive bytes with the least significant byte at an even address information is transferred over both halves of the data bus see Figure 3 3 A19 1 select th...

Страница 84: ...3 3 BUS INTERFACE UNIT Figure 3 2 16 Bit Data Bus Byte Transfers Even Byte Transfer Odd Byte Transfer A19 1 D15 8 D7 0 A0 Low BHE High A19 1 D15 8 D7 0 A0 High BHE Low Y X Y 1 X 1 Y X Y 1 X 1 A1104 0A...

Страница 85: ...devices e g ROM EPROM Flash During the byte read an external device can drive both halves of the bus and the BIU automatically accesses the correct half During the byte write op eration the BIU drives...

Страница 86: ...te and word transfers to even or odd addresses all transfer data over the same 8 bit bus Byte transfers to even or odd addresses transfer information in one bus cycle Word transfers to even or odd add...

Страница 87: ...memory cycles Memory mapped I O allows the full power of the instruction set to be used when communicating with peripheral devices I O read and I O write bus cycles use a separate I O address space On...

Страница 88: ...ressed word data 3 3 2 8 Bit Bus Memory and I O Requirements An 8 bit bus interface has no restrictions on implementing the memory or I O interfaces All transfers bytes and words occur over the single...

Страница 89: ...T3 and T4 A TI idle state occurs when no bus cycle is pending Multiple T3 states occur to generate wait states The TW symbol represents a wait state The operation of a bus cycle can be separated into...

Страница 90: ...and continues through T4 Figure 3 9 illustrates the T state relationship of the two phases Figure 3 8 BIU State Diagram Bus Ready Request Pending HOLD Deasserted Bus Not Ready Halt Bus Cycle Bus Read...

Страница 91: ...E provides a strobe to latch physical address information Address is presented on the multi plexed address data bus during T1 see Figure 3 10 The falling edge of ALE occurs during the middle of T1 and...

Страница 92: ...1 4 2 3 5 6 1 2 3 4 5 6 T T T T T T CHOV CLOV AVLL CHOV CLOF LLAX Valid Valid Clock high to ALE high S2 0 valid Clock low to address valid BHE valid Address valid to ALE low address setup to ALE Cloc...

Страница 93: ...2 S1 S0 0 0 0 Interrupt Acknowledge 0 0 1 I O Read 0 1 0 I O Write 0 1 1 Halt 1 0 0 Instruction Prefetch 1 0 1 Memory Read 1 1 0 Memory Write 1 1 1 Idle passive 4 I I STB 8 8 O O ALE Latched Address S...

Страница 94: ...before T4 or TI 3 4 3 Wait States Wait states extend the data phase of the bus cycle Memory and I O devices that cannot provide or accept data in the minimum four CPU clocks require wait states Figur...

Страница 95: ...T T T T T CLOV CLOV CLIS CLOV CLIH WHDX RHAV Clock low to valid RD WR active Write data valid Clock low to status inactive Data input valid to clock low Clock valid to RD WR inactive Data input HOLD...

Страница 96: ...Bus Cycle with Wait States Figure 3 14 ARDY and SRDY Pin Block Diagram ALE S2 0 A19 16 AD15 0 READY WR CLKOUT T1 T2 T3 TW TW T4 Valid Address Address Valid Write Data A1040 0A D Q ARDY BUS READY CLKOU...

Страница 97: ...s in no wait states Figure 3 15 Generating a Normally Not Ready Bus Signal A normally ready signal remains high at all times except when the selected device needs to signal a not ready condition For a...

Страница 98: ...is inactive prior to the phase 2 clock edge or ARDY is inactive prior to the phase 1 clock edge A single latch captures the state of the SRDY input see Figure 3 14 on page 3 15 SRDY must be valid by t...

Страница 99: ...performance suffers because the instruction prefetch queue cannot be kept full Integrated peripheral perfor mance suffers because the maximum bus bandwidth decreases 3 4 4 Idle States Under most opera...

Страница 100: ...WAIT A1045 0A ARDY CLKOUT In a Normally Ready system a wait state will be inserted when 1 2 are met Assumes SRDY is low T2 T3 TW ARDY CLKOUT Alternatively in a Normally Ready system a wait state will...

Страница 101: ...lustrates a typical read cycle Table 3 2 lists the three types of read bus cycles Figure 3 20 illustrates a typical 16 bit interface connection to a read only device interface The same example applies...

Страница 102: ...han the equation result indicates a buffer fight A buffer fight means two or more devices are driving the bus at the same time This can lead to short circuit conditions resulting in large current spik...

Страница 103: ...alue on the bus is ignored RFSH has the same bus timing as BHE Figure 3 20 Read Only Device Interface 3 5 2 Write Bus Cycles Figure 3 21 illustrates a typical write bus cycle The bus cycle starts with...

Страница 104: ...Cycle Types Status Bits Bus Cycle Type S2 S1 S0 0 1 0 Write I O Initiated by executing IN OUT INS OUTS instructions or by the DMA Unit A15 0 select the desired I O port A19 16 are driven to zero see...

Страница 105: ...rising edge of WR TAW TCW and TDW de fine the minimum data setup requirements The value calculated by their respective equations must be greater than the device requirements To increase the calculate...

Страница 106: ...Con trol Unit for more information The BIU controls the bus cycles required to fetch vector infor mation from the peripheral device then passes the information to the CPU These bus cycles collectivel...

Страница 107: ...Bus Cycle T1 T2 T3 T4 CLKOUT ALE TI TI T1 T2 T3 AD15 0 AD7 0 RD WR BHE DEN DT R LOCK S2 0 INTA0 INTA1 A19 16 A15 8 NOTE Vector Type is read from AD7 0 only INTA occurs during T2 in slave mode Note A15...

Страница 108: ...ge bus cycles However you can add wait states to interrupt acknowledge cycles if the PCB is located at any other address 3 5 3 1 System Design Considerations Although ALE is generated for both bus cyc...

Страница 109: ...is enabled A DMA request is generated except when Powerdown mode is enabled A refresh request is generated except when Powerdown mode is enabled Figure 3 25 shows the operation of a HALT bus cycle Th...

Страница 110: ...state Bus control pins force their inactive state Figure 3 3 lists the state of each pin after entering the HALT bus state Table 3 6 HALT Bus Cycle Pin States Pin s Pin State No Powerdown or Idle Mod...

Страница 111: ...s time if Idle Mode is enabled When Idle Mode is not enabled the AD15 0 AD7 0 bus either floats or drives previous write data and A15 8 8 bit device continues to drive its previous value 4 The A19 16...

Страница 112: ...The BIU returns to the HALT bus state after it completes the desired bus operation However the BIU does not execute another bus HALT cycle i e ALE and bus cycle status are not regenerated Figures 3 26...

Страница 113: ...e CLKOUT AD15 0 AD7 0 ALE A15 8 A19 16 Address Note 1 Note 2 Note 3 NOTES 1 Previous bus cycle value 2 Only occurs for BHE on the first refresh bus cycle after entering HALT 3 BHE 1 for 16 bit device...

Страница 114: ...the BIU to exit HALT The first bus operations to occur after exiting HALT are read cycles to reload the CS IP registers Figure 3 29 and Figure 3 30 show how the HALT bus state is exited when an NMI or...

Страница 115: ...gure 3 29 Exiting HALT Powerdown Mode CLKOUT ALE A15 8 A19 16 S2 0 NMI 8 1 2 clocks to first vector fetch Time is determined by PDTMR 4 1 2 clocks min NOTE Previous bus cycle address value BHE RFSH 1...

Страница 116: ...ying the BIU interface The following sections deal with topics to enhance or modify the operation of the BIU CLKOUT AD15 0 AD7 0 ALE A15 8 A19 16 Note 3 NOTES 1 For NMI delay 4 1 2 clocks For INTx del...

Страница 117: ...or I O device cannot float its outputs in time to prevent bus contention even at reset Figure 3 31 DEN and DT R Timing Relationships The circuit shown in Figure 3 32 illustrates how to use transceive...

Страница 118: ...bus accesses Figure 3 33 illustrates how to use chip selects to qualify DEN DT R always connects directly to the transceiver However an inverter may be required if the po larity of DT R does not matc...

Страница 119: ...s occurs then continue program execution One way to synchronize software execution with hardware events requires the use of interrupts Executing a HALT instruction suspends program execution until an...

Страница 120: ...ystem operation priority of the shared system bus is determined by the arbitration circuits on a cycle by cycle basis As each CPU requires a transfer over the sys tem bus it requests access to the bus...

Страница 121: ...not require these signals because they use the 80187 math coprocessor which has an I O port interface similar to that of a peripheral device The queue status signals QS0 and QS1 indicate the state of...

Страница 122: ...ing the bus After HLDA goes active the requesting device can take control of the local bus and remains in control of the bus until HOLD is removed 3 7 1 Entering Bus HOLD In responding to the hold req...

Страница 123: ...d request occurs just before the BIU begins another bus cycle Table 3 8 Signal Condition Entering HOLD Signal HOLD Condition A19 16 S2 0 RD WR DT R BHE RFSH LOCK These signals float one half clock bef...

Страница 124: ...DMA request or refresh bus cycle has completed Refresh bus cycles have a higher priority than hold bus requests A bus hold request cannot separate the bus cycles associated with a DMA transfer worst c...

Страница 125: ...short HLDA pulse and continues to wait for HLDA to be asserted while the BIU waits for HOLD to be deasserted The circuit shown in Figure 3 37 can be used to latch HLDA HLDA CLKOUT HOLD NOTES 1 HLDA is...

Страница 126: ...iting HOLD Figure 3 38 shows the timing associated with exiting the bus hold state Normally a bus operation e g an instruction prefetch occurs just after HOLD is released However if no bus cycle is pe...

Страница 127: ...ghest to lowest 1 Instruction execution read write following a non pipelined effective address calculation 2 Refresh bus cycles 3 Bus hold request 4 Single step interrupt vectoring sequence 5 Non Mask...

Страница 128: ...code execution The following points apply to sequences of related execution cycles The second read write cycle of an odd addressed word operation is inseparable from the first bus cycle The second rea...

Страница 129: ......

Страница 130: ...4 Peripheral Control Block...

Страница 131: ......

Страница 132: ...ters that cover the associated peripheral Accessing the Peripheral Con trol Block on page 4 4 discusses how the registers are accessed and outlines considerations for reading and writing them 4 2 PCB...

Страница 133: ...ve mode If SL is clear it operates in master mode MEM Memory I O 0 If MEM is set the PCB is located in memory space If MEM is clear the PCB is located in I O space R19 8 PCB Base Address Upper Bits 0F...

Страница 134: ...Reserved 58H T1CNT 98H Reserved D8H D1TC 1AH Reserved 5AH T1CMPA 9AH Reserved DAH D1CON 1CH Reserved 5CH T1CMPB 9CH Reserved DCH Reserved 1EH Reserved 5EH T1CON 9EH Reserved DEH Reserved 20H Reserved...

Страница 135: ...Peripheral Control Block Address data and control information is driven on the external pins as with an ordinary bus cycle Information returned by an external device is ignored even if the access doe...

Страница 136: ...addresses work normally but only a byte will be read For example IN AL DX will not transfer DX into AX only AL is modified No problems will arise if the following recommendations are adhered to Word...

Страница 137: ...ns should be used for the registers in the Peripheral Control Block of an 80C188 Modular Core family member This requires half the bus cycles of word operations Byte opera tions are valid only for eve...

Страница 138: ...5 1 Considerations for the 80C187 Math Coprocessor Interface Systems using the 80C187 math coprocessor interface must not relocate the Peripheral Control Block to location 0000H in I O space The 80C1...

Страница 139: ......

Страница 140: ...5 ClockGenerationand Power Management...

Страница 141: ......

Страница 142: ...generation circuit Figure 5 1 includes a crystal oscillator a divide by two counter power save powerdown idle and reset circuitry See Power Management on page 5 10 for a discussion of power managemen...

Страница 143: ...reactive and forces the oscillator back toward the crystal s nominal frequency Figure 5 2 Ideal Operation of Pierce Oscillator Figure 5 3 shows the actual microprocessor crystal connections For low fr...

Страница 144: ...oximately equal the 20 pF load capacitor CX2 used alone in the fundamental mode circuit Figure 5 3 Crystal Connections to Microprocessor Choosing C1 as 200 pF at least 10 times the value of the load c...

Страница 145: ...the above three criteria yields Table 5 1 This table shows suggested standard inductor values for various processor frequencies The equivalent capacitance is about 15 pF Table 5 1 Suggested Values for...

Страница 146: ...ESR is proportional to crystal thickness inversely proportional to frequency A lower value gives a faster startup time but the specification is usually not important in microprocessor applications Shu...

Страница 147: ...w times stated in the data sheet Selecting an ex ternal clock oscillator is more straightforward than selecting a crystal 5 1 3 Output from the Clock Generator The crystal oscillator output drives a d...

Страница 148: ...The device pins will assume their reset states on the second falling edge of CLKIN following the assertion of RESIN Figure 5 5 Simple RC Circuit for Powerup Reset The processor exits reset identicall...

Страница 149: ...able to RESIN high approximately 32 CLKIN periods UCS LCS MCS3 0 PCS6 0 T0OUT T1OUT NPS NOTE CLKOUT synchronization occurs approximately 1 1 2 CLKIN periods after RESIN is sampled low CLKIN CLKOUT A19...

Страница 150: ...eriods after recognition of RESIN in the logic high state If an alternate bus master asserts HOLD during reset the processor immediately asserts HLDA and will not prefetch instructions RESIN AD15 0 S2...

Страница 151: ...the processor is likely to lose its present state needing a reset to resume normal operation An 80C186 Modular Core microprocessor is fully static The CPU stores its current state in flip flops not ca...

Страница 152: ...on the clock signal is routed only to the integrated peripheral devices CLKOUT continues toggling The clocks to the CPU core Execution and Bus Interface Units freeze in a logic low state Idle mode red...

Страница 153: ...instruction is executed The PWRDN bit must be cleared when setting the IDLE bit otherwise Idle mode is not armed PWRDN Powerdown Mode 0 Setting the PWRDN bit forces the CPU to enter the Powerdown mode...

Страница 154: ...ore clock begins to toggle on the falling CLKOUT edge three clocks after the processor samples the DMA request pin After one idle T state the processor runs the DMA cycle The BIU uses the ready wait s...

Страница 155: ...oprocessor asserts HLDA one cycle after the core clock starts The core clock turns off and the processor deasserts HLDA one cycle after the external bus master deas serts HOLD Figure 5 11 HOLD HLDA Du...

Страница 156: ...MI occurs The NMI signal does not need the mask and priority checks that a maskable interrupt does This results in a considerable differ ence in clock restart time between an NMI and an unmasked inter...

Страница 157: ...name example_80C186_power_management_code FUNCTION This function reduces CPU power consumption SYNTAX extern void far power_mgt int mode INPUTS mode 00 Active Mode 01 Powerdown Mode 02 Idle Mode 03 Ac...

Страница 158: ...T2 phase of the HLT instruction the core generates a signal called Enter_Powerdown Enter_Powerdown immediately disables the internal CPU core and peripheral clocks The pro cessor disables the oscillat...

Страница 159: ...ives the user control over the gating of the crystal oscillator to the internal clocks The strong P channel device is always on except during exit from Powerdown mode This pullup keeps the powerdown c...

Страница 160: ...his divider operates in addition to the divide by two counter see Figure 5 1 on page 5 1 NOTE Power Save mode can be used to stretch bus cycles as an alternative to wait states Possible clock divisor...

Страница 161: ...defined by F1 0 Clearing this bit disables Power Save mode and forces the CPU to operate at full speed PSEN is automatically cleared whenever an interrupt occurs F1 0 Clock Division Factor 0H These bi...

Страница 162: ...rrupts If an NMI occurs or an unmasked interrupt request has sufficient priority to pass to the core Power Save mode will end The PSEN bit clears and the clock resumes full speed operation at the fall...

Страница 163: ...qu 8000H Power Save enable bit data segment public data FreqTable dw 1 4 8 16 32 64 0 0 data ends lib_80C186 segment public code assume cs lib_80C186 ds data public _power_save _power_save proc far pu...

Страница 164: ...currently With Idle mode alone rated power consumption typically drops a third or more Power Save mode multiplies that reduction further according to the selected clock divisor Overall power consumpti...

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Страница 166: ...6 Chip Select Unit...

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Страница 168: ...bles the SRAM device Also note that any bus cycle with an address starting at 30000H 50000H 70000H and so on also selects the SRAM device Decoding more address bits solves the problem of a chip select...

Страница 169: ...coder circuits The Chip Select Unit activates a chip select for bus cycles initiated by the CPU DMA Control Unit or Refresh Control Unit Six of the chip selects map only into memory address space whil...

Страница 170: ...S MCS3 MCS2 MCS1 MCS0 Base Base 0 Base 128 Base 256 Base 384 Base 512 Base 640 Base 768 PCS0 PCS1 PCS2 PCS3 PCS4 Base PCS5 PCS6 MUX A B A B A1 A2 EX Control Bit Internal Address Bit Memory I O Selecto...

Страница 171: ...starting address is programmed in the UMCS register Figure 6 5 on page 6 7 The LCS chip select al ways starts at address location 0H its block size and thus its ending address is programmed in the LM...

Страница 172: ...enabled 2 The bus cycle status matches the default or programmed type memory or I O 3 The bus cycle address is within the default or programmed block size 4 The bus cycle is not accessing the Peripher...

Страница 173: ...6 4 1 Initialization Sequence Chip selects do not have to be initialized in any specific order However the following guidelines help prevent a system failure 1 Initialize local memory chip selects 2...

Страница 174: ...sable 0H When R2 is clear bus ready must be active to complete a bus cycle When R2 is set R1 0 control the number of bus wait states and bus ready is ignored R1 0 Wait State Value 3H R1 0 define the m...

Страница 175: ...When R2 is clear bus ready must be active to complete a bus cycle When R2 is set R1 0 control the number of bus wait states and bus ready is ignored R1 0 Wait State Value 3H R1 0 define the minimum nu...

Страница 176: ...able X When R2 is clear bus ready must be active to complete a bus cycle When R2 is set R1 0 control the number of bus wait states and bus ready is ignored R1 0 Wait State Value 3H R1 0 define the min...

Страница 177: ...R2 Bus Ready Disable X When R2 is clear bus ready must be active to complete a bus cycle When R2 is set R1 0 control the number of bus wait states and bus ready is ignored R1 0 Wait State Value 3H R1...

Страница 178: ...CS6 4 X Applies only to PCS6 4 When R2 is clear bus ready must be active to complete a bus cycle When R2 is set R1 0 control the number of bus wait states and bus ready is ignored R1 0 Wait State Valu...

Страница 179: ...ng or ending addresses and block sizes This section describes how to control the active range of each chip select 6 4 2 1 UCS Active Range The UCS starting address is 100000H 1 Mbyte minus the block s...

Страница 180: ...and the block size programmed in the MPCS register see Table 6 4 and Figure 6 10 The base address must be an integer multiple of the block size Table 6 5 lists the allowable block sizes and base addr...

Страница 181: ...o 0 0 1 X X X X 128 U16 13 must be zero 0 1 X X X X X 256 U17 13 must be zero 1 X X X X X X 512 U18 13 must be zero NOTE If U19 is one will overlap UCS X don t care but should be 0 for future compatib...

Страница 182: ...eripheral devices operate properly using three or fewer wait states However accessing such devices as a dual port memory an expansion bus interface a system bus interface or remote peripheral devices...

Страница 183: ...led chip selects programmed to cover the same physical address space This is true if any portion of the chip selects address ranges overlap i e chip selects ranges do not need to overlap completely to...

Страница 184: ...bus cycles The PCS chip selects activate for either memory or I O bus cycles depending on the state of the MS bit in the MPCS register Figure 6 9 on page 6 11 Memory bus cycles consist of memory read...

Страница 185: ...hip Selects During HOLD 6 6 EXAMPLES The following sections provide examples of programming the Chip Select Unit to meet the needs of a particular application The examples do not go into hardware anal...

Страница 186: ...UNIT Figure 6 13 Typical System L a t c h Processor ALE AD Bus Addr Bus PCS1 DRQ CE D R A M 256K ARDY 20 MCS3 0 UCS PCS0 LCS SRAM 32K Floppy Disk Control CE CE EPROM 128K CE DRQ DACK A0 A19 16 AD15 0...

Страница 187: ...1024 EPROM_SIZE Start address in Kbytes EPROM_WAIT EQU 1 Wait states The UMCS register values are calculated using the above system contraints and the equations below UMCS_VAL EQU EPROM_BASE SHL 6 OR...

Страница 188: ...E OR PCS_FUNC OR IO_RDY OR IO_WAIT I O is selected using the PCS0 chip select Wait states assume operation at 16 MHz For this example the Floppy Disk Controller is connected to PCS2 and PCS1 provides...

Страница 189: ...elect mov ax PACS_VAL out dx al CODE ENDS Power on reset code to get started ASSUME CS POWER_ON POWER_ON SEGMENT AT 0FFFFH mov dx UMCS_REG point to UMCS register mov ax UMCS_VAL reprogram UMCS to matc...

Страница 190: ...7 Refresh Control Unit...

Страница 191: ......

Страница 192: ...tegrating the Refresh Control Unit into the processor allows an external DRAM controller to use chip selects wait state logic and status lines Figure 7 1 Refresh Control Unit Block Diagram Refresh Clo...

Страница 193: ...9 bit address counter forms the refresh addresses supporting any dynamic memory devices with up to 9 rows of memory cells 9 refresh address bits This includes all practical DRAM sizes for the process...

Страница 194: ...er wise the time between refresh requests would be a function of varying bus activity When the BIU services the refresh request it clears the request and increments the refresh address Counter Load Co...

Страница 195: ...on page 7 8 Figure 7 3 Refresh Address Formation Refresh address bits RA12 10 are always zero A linear feedback shift counter generates address bits RA9 1 and RA0 is always one The counter does not c...

Страница 196: ...ular Core family DRAM interfaces use only this method Others are not dis cussed here The DRAM controller s purpose is to use the processor s address status and control lines to gen erate the multiplex...

Страница 197: ...e CAS When CAS is present the dummy read cycle becomes a true read cycle the DRAM drives the bus and the DRAM row still gets refreshed Both RAS and CAS stay active during any wait states They go inact...

Страница 198: ...ine the correct value for the RFTIME Register value Figure 7 5 Formula for Calculating Refresh Interval for RFTIME Register If the processor enters Power Save mode the refresh rate must increase to of...

Страница 199: ...defines the time between refresh requests The higher the value the longer the time between requests The down counter decrements every fall ing CLKOUT edge regardless of core activity When the counter...

Страница 200: ...esh Control Unit clears both the counter and the corresponding counter bits in the control register Register Name Refresh Clock Interval Register Register Mnemonic RFTIME Register Function Sets refres...

Страница 201: ...ontrols Refresh Unit operation Bit Mnemonic Bit Name Reset State Function REN Refresh Control Unit Enable 0 Setting REN enables the Refresh Unit Clearing REN disables the Refresh Unit RC8 0 Refresh Co...

Страница 202: ...M to refresh clock_time DRAM refresh rate OUTPUTS None NOTE Parameters are passed on the stack as required by high level languages RFBASE equ xxxxh substitute register offset RFTIME equ xxxxh RFCON eq...

Страница 203: ...ernate master removes HOLD The user must design the system so that the processor can re gain bus control If the alternate master asserts HOLD after the processor starts the refresh cycle the CPU will...

Страница 204: ...rted signaling need to run DRAM refresh cycles less than T CLOV 2 External bus master terminates use of the bus 3 HOLD deasserted greater than TCLIS 4 Hold may be reasserted after one clock 5 Lines co...

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Страница 206: ...8 Interrupt Control Unit...

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Страница 208: ...8259A See Figure 8 15 on page 8 24 This mode can be useful in larger system designs The Interrupt Control Unit has the following features Programmable priority of each interrupt source Individual mask...

Страница 209: ...diagram of the Interrupt Control Unit in Master mode In this mode the ICU processes all interrupt requests both external and internal The three timer interrupt requests share a single input while the...

Страница 210: ...able or unmask enable each interrupt source by setting or clearing the corresponding bit in the Interrupt Mask register 8 2 1 2 Interrupt Priority One critical function of the Interrupt Control Unit i...

Страница 211: ...ogrammer explicitly enables interrupts Enabling maskable in terrupts within an interrupt handler allows interrupts to be nested Otherwise interrupts are pro cessed sequentially one interrupt handler m...

Страница 212: ...e interrupt acknowledge the Interrupt Control Unit clears the corresponding bit in the Interrupt Request register and sets the corresponding bit in the In Service register The In Service register keep...

Страница 213: ...the interrupt type in this case type 12 to the CPU 5 The Interrupt Control Unit clears the INT0 bit in the Interrupt Request register and sets the INT0 bit in the In Service register 6 The CPU execut...

Страница 214: ...the Interrupt Request bit remains set When the timer interrupt is acknowledged the shared In Service bit is set No other timer inter rupts can occur when the In Service bit is set If a second timer i...

Страница 215: ...interrupt from the 8259A While the interrupt handler is executing the 8259A receives a higher priority interrupt from one of its sourc es The 8259A applies its own priority criteria to that interrupt...

Страница 216: ...s case the CPU runs an external interrupt acknowledge cycle to fetch the interrupt type from the 8259A see Interrupt Acknowledge Bus Cycle on page 3 25 8 3 5 Polling In some applications it is desirab...

Страница 217: ...riggered 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 trigg...

Страница 218: ...8 3 Interrupt Control Unit Registers in Master Mode Register Name Offset Address INT3 Control 3EH INT2 Control 3CH INT1 Control 3AH INT0 Control 38H DMA0 Control 34H DMA1 Control 36H Timer Control 32H...

Страница 219: ...mask bit is the same as the one in the Interrupt Mask register Modifying a bit in either register also mod ifies that same bit in the other register The Interrupt Control registers for the external in...

Страница 220: ...register for the internal interrupt sources Bit Mnemonic Bit Name Reset State Function MSK Interrupt Mask 1 Clear to enable interrupts from this source PM2 0 Priority Level 111 Defines the priority l...

Страница 221: ...pins Bit Mnemonic Bit Name Reset State Function LVL Level trigger 0 Selects the interrupt triggering mode 0 edge triggering 1 level triggering MSK Interrupt Mask 1 Clear to enable interrupts from thi...

Страница 222: ...CAS Cascade Mode 0 Set to enable cascade mode LVL Level trigger 0 Selects the interrupt triggering mode 0 edge triggering 1 level triggering The LVL bit must be set when external 8259As are cascaded...

Страница 223: ...Set a mask bit to disable interrupts from the corresponding source The mask bit is the same as the one in the Interrupt Control register Modifying a bit in either register also modifies that same bit...

Страница 224: ...ables all interrupts of any priority Register Name Interrupt Mask Register Register Mnemonic IMASK Register Function Masks individual interrupt sources Bit Mnemonic Bit Name Reset State Function INT3...

Страница 225: ...The Interrupt Control Unit uses the In Service register to support interrupt nesting Register Name Priority Mask Register Register Mnemonic PRIMSK Register Function Masks lower priority interrupt sou...

Страница 226: ...Function Indicates which interrupt handlers are in process Bit Mnemonic Bit Name Reset State Function INT3 0 External Interrupt In Service 0000 0 A bit is set to indicate that the corresponding extern...

Страница 227: ...upt Reading the Poll Status register Figure 8 12 will merely transmit the status of the polling bits without modifying any of the other Interrupt Controller registers Figure 8 11 Poll Register Registe...

Страница 228: ...0 bits with the interrupt type of the interrupt whose In Service bit you wish to clear For example to clear the In Service bit for INT2 write 000EH to the EOI reg ister The timer interrupts share an...

Страница 229: ...t and is cleared when the interrupt request is acknowledged Any number of bits can be set at any one time Register Name End of Interrupt Register Register Mnemonic EOI Register Function Used to issue...

Страница 230: ...t processes only the internal interrupt re quests and acts as an interrupt input to the external 8259A In simplest terms the Interrupt Control Unit behaves like a cascaded 8259A to the master 8259A Se...

Страница 231: ...INTERRUPT CONTROL UNIT 8 24 Figure 8 15 Interrupt Control Unit in Slave Mode 8259A 82C59A INT INTA Cascade Address Decode INT0 INTA Select 80186 Modular Core VCC IRQ A1194 A0...

Страница 232: ...NT0 Control registers with individual Timer 0 Timer 1 and Timer 2 Control registers The remaining registers retain the same functions as in Master mode however some bit positions change to accommodate...

Страница 233: ...B Offset Address INT3 Control not used 3EH INT2 Control not used 3CH INT1 Control Timer 2 Control 3AH INT0 Control Timer 1 Control 38H DMA1 Control DMA1 Control 36H DMA0 Control DMA0 Control 34H Timer...

Страница 234: ...5 to the VT2 0 bits Register Name Interrupt Vector Register Slave Mode only Register Mnemonic INTVEC Register Function Specifies the five most significant bit of the interrupt vector types for the in...

Страница 235: ...s the bit positions for Slave mode Figure 8 19 Request Mask and In Service Registers Register Name End of Interrupt Register in Slave Mode Register Mnemonic EOI Register Function Used to issue the EOI...

Страница 236: ...e slave select input to the Interrupt Control Unit During the second inter rupt acknowledge cycle the highest priority slave interrupt controller transfers the interrupt type of its highest priority i...

Страница 237: ...nterrupt Control register for each interrupt source For external interrupt pins select edge or level triggering For INT0 or INT1 enable cascade mode special fully nested mode or both if you wish to us...

Страница 238: ...errupt controller to provide two cascaded interrupt inputs through an external 8259A connected to INT0 and INTA0 and two direct interrupt inputs connected to INT1 and INT3 The default priorities are u...

Страница 239: ...INTERRUPT CONTROL UNIT 8 32...

Страница 240: ...9 Timer Counter Unit...

Страница 241: ......

Страница 242: ...at the end see Figure 9 2 No connection exists between the counter element s se quencing through timer register banks and the Bus Interface Unit s sequencing through T states Timer operation and bus i...

Страница 243: ...ter Unit Block Diagram Transition Latch Synchronizer Transition Latch Synchronizer Timer 0 Registers Timer 1 Registers Timer 2 Registers Output Latch Output Latch T0 Out T1 Out Counter Element CPU Int...

Страница 244: ...T1IN resolution time setup time not met 3 Modified count value written into Timer 0 count register 4 T1IN resolution time count value written into Timer 1 count register 5 T1IN resolution time T0OUT T...

Страница 245: ...o Hi transition on input pin since last service Done External Clocking EXT 1 Retrigger RTG 1 Yes No No Yes Yes Did Timer 2 Reach Maxcount Last Service State Prescaler On P 1 Lo to Hi transition on inp...

Страница 246: ...Use A Counter Compare B Counter Compare A Continuous Mode CONT 1 Yes No Done Clear RIU Bit TOUT Pin Driven High Continued From A No Yes Done Clear Enable Bit Stop Counting No Continuous Mode CONT 1 Ye...

Страница 247: ...nly in single maximum count mode Figure 9 4 It can be used as a free running clock and as a prescaler to Timers 0 and 1 Timer 2 can be clocked only internally at CLKOUT frequency Timer 2 can also gene...

Страница 248: ...uest when the Count register equals a Maximum Count register Clear to disable interrupt requests RIU Register In Use X Indicates which compare register is in use When set the current compare register...

Страница 249: ...KOUT This bit is ignored with external clocking EXT 1 EXT External Clock X Set to use external clock clear to use internal clock The RTG and P bits are ignored with external clocking EXT set ALT Alter...

Страница 250: ...rupt request when the Count register equals a Maximum Count register Clear to disable interrupt requests MC Maximum Count X This bit is set when the counter reaches a maximum count The MC bit must be...

Страница 251: ...NT T1CNT T2CNT Register Function Contains the current timer count Bit Mnemonic Bit Name Reset State Function TC15 0 Timer Count Value XXXXH Contains the current count of the associated timer 15 0 T C...

Страница 252: ...nt Compare A and B 4 Program the Timer Control register to enable the timer When using Timer 2 to prescale another timer enable Timer 2 last If Timer 2 is enabled first it will be at an unknown point...

Страница 253: ...cing scheme Timer 2 can use only the internal clock as a timer event Timers 0 and 1 can also use Timer 2 reaching its maximum count as a timer event In this config uration Timer 0 or Timer 1 increment...

Страница 254: ...used The timer will count to the value contained in Maxcount Compare A and reset to zero Timer 2 can operate only in this mode Timers 0 and 1 can also use dual maximum count mode In this mode Maxcount...

Страница 255: ...ccurs one clock after the counter element services the timer when the maximum count is reached see Figure 9 9 With external clocking the time between a transition on a timer input and the correspondin...

Страница 256: ...timer has an Enable EN bit in its Control register to allow or prevent timer counting The Inhibit INH bit controls write accesses to the EN bit Timers 0 and 1 can be programmed to use their input pin...

Страница 257: ...is generated each time the value in Maxcount Compare A or Max count Compare B is reached If the interrupt is disabled after a request has been generated but before a pending interrupt is serviced the...

Страница 258: ...it Application Examples The following examples are possible applications of the Timer Counter Unit They include a real time clock a square wave generator and a digital one shot 9 3 3 Real Time Clock E...

Страница 259: ...me to second second to set time to T2Compare T2CMPA value see note below OUTPUTS None NOTE Parameters are passed on the stack as required by high level languages For a CLKOUT of 16Mhz f timer2 16Mhz 4...

Страница 260: ...r ax ax set interrupt vector mov ds ax mov si 4 timer_2_int mov word ptr ds si offset timer_2_interrupt_routine inc si inc si mov ds si cs pop ds mov ax hour set time mov _hour al mov ax minute mov _m...

Страница 261: ...t_ctl bump_second mov _msec 0 reset millisecond cmp _minute 59 has 1 minute passed jae bump_minute inc _second jmp short reset_int_ctl bump_minute mov _second 0 reset second cmp _minute 59 has 1 hour...

Страница 262: ...S None NOTE Parameters are passed on the stack as required by high level Languages T1CMPA equ xxxxH substitute register offsets T1CMPB equ xxxxH T1CNT equ xxxxH T1CON equ xxxxH lib_80186 segment publi...

Страница 263: ...n SYNTAX extern void far one_shot int CMPB INPUTS CMPB This is the T1CMPB value required to generate a pulse of a given pulse width This value is calculated from the formula below CMPB req_pulse_width...

Страница 264: ...dx al mov dx T1CMPA set time before t_shot to 0 mov ax 1 out dx al mov dx T1CMPB set pulse time mov ax _CMPB out dx al mov dx T1CON mov ax C002H start Timer 1 out dx al CountDown in ax dx read in T1C...

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Страница 266: ...10 Direct Memory Access Unit...

Страница 267: ......

Страница 268: ...en releases con trol of the bus and the DMA controller performs the transfer In many cases the CPU releases the bus and continues to execute instructions from the prefetch queue If the DMA transfers a...

Страница 269: ...exceeded its programmed transfer limit Every DMA transfer consists of two distinct bus cycles a fetch and a deposit see Figure 10 1 on page 10 2 During the fetch cycle the byte or word is read from th...

Страница 270: ...t pointer for the source of data and a twenty bit pointer for the destination of data The twenty bit pointers allow access to the full 1 Mbyte of memory space The DMA Unit views memory as a linear uns...

Страница 271: ...For example a disk controller in the process of reading data from a disk would use a source synchronized request data would be moving from the disk to memory A destination synchronized request origina...

Страница 272: ...states at the end of the deposit cycle Figure 10 4 The two idle states extend the DMA cycle to allow the destination device to deassert its DRQ pin four clocks before the end of the cycle If the two...

Страница 273: ...ld point to the waveform data the destination would point to the A D converter and Timer 2 would request a transfer every 22 microseconds See Timed DMA Transfers on page 10 26 10 1 5 2 Unsynchronized...

Страница 274: ...disarms itself when the transfer count value reaches zero No further DMA transfers take place on the channel until it is re armed by direct programming Unsynchronized transfers always terminate when t...

Страница 275: ...ognize DMA cycles that access I O space above 64K 10 1 10 The Two Channel DMA Unit Two DMA channels are combined with arbitration logic to form the DMA Unit see Figure 10 5 10 1 10 1 DMA Channel Arbit...

Страница 276: ...ree to perform its transfer even though the higher priority channel has not completed all of its transfers Channel 1 regains the bus at the end of channel 0 s trans fer The transfers will alternate as...

Страница 277: ...A total of six Peripheral Control Block registers configure each DMA channel 10 2 1 DMA Channel Parameters The first step in programming the DMA Unit is to set up the parameters for each channel 10 2...

Страница 278: ...in the normal 64K I O space only the high order bits in the pointer registers must be cleared Figure 10 7 DMA Source Pointer High Order Bits Register Name DMA Source Address Pointer High Register Mnem...

Страница 279: ...crement and decrement bits for a pointer are programmed to the same value then the pointer remains constant The programmed data width byte or word for the channel automatically controls the amount tha...

Страница 280: ...bits of the DMA Destination pointer Bit Mnemonic Bit Name Reset State Function DDA19 16 DMA Destination Address XXXXH DDA19 16 are driven on A19 16 during the deposit phase of a DMA transfer NOTE Res...

Страница 281: ...increment or decrement the pointer registers by two for each transfer while byte trans fers modify the pointer registers by one Register Name DMA Destination Address Pointer Low Register Mnemonic DxDS...

Страница 282: ...e destination pointer after each transfer See Note SMEM Source Address Space Select X Selects memory or I O space for the source pointer Set SMEM to select memory space clear SMEM to select I O space...

Страница 283: ...ynchronization SYN1 SYN0 Synchronization Type 0 0 Unsynchronized 0 1 Source synchronized 1 0 Destination synchronized 1 1 Reserved do not use P Relative Priority X Set P to select high priority for th...

Страница 284: ...e DMA Control Register Register Mnemonic DxCON Register Function Controls DMA channel parameters Bit Mnemonic Bit Name Reset State Function CHG Change Start Bit X Set CHG to enable modifying the STRT...

Страница 285: ...er Figure 10 11 on page 10 15 NOTE The combination SYN1 0 11 is reserved and will result in unpredictable operation When IDRQ is set internal requests selected the channel must always be programmed fo...

Страница 286: ...DMA Control Register Figure 10 11 on page 10 15 must be set to generate an interrupt request 10 2 1 8 Setting the Relative Priority of a Channel The priority of a channel is controlled by the Priority...

Страница 287: ...n when the interrupt controller is in slave mode 10 2 3 Initializing the DMA Unit Use the following sequence when programming the DMA Unit 1 Program the source and destination pointers for all used ch...

Страница 288: ...s The maximum DMA transfer rate is a function of processor operating frequency and synchroni zation mode For unsynchronized and source synchronized transfers the 80C186 Modular Core can transfer two b...

Страница 289: ...A is in progress Latched status line S6 can be used as a qualifier to the chip select for situations in which the chip select line will be ac tive for both DMA and normal data accesses 10 4 DMA UNIT E...

Страница 290: ...A_1 to DEST_DATA_1 The first step is to calculate the proper values for the source and destination pointers MOV AX SEG SOURCE_DATA_1 ROL AX 4 GET HIGH 4 BITS MOV BX AX SAVE ROTATED VALUE AND AX 0FFF0H...

Страница 291: ...SYNCHRONIZED BURST IS NOW RUNNING ON THE BUS NOW SET UP CHANNEL 1 TO SERVICE THE DISK CONTROLLER FOR THIS EXAMPLE WE WILL ONLY BE READING FROM THE DISK THE SOURCE IS THE I O PORT FOR THE DISK CONTROLL...

Страница 292: ...E MEMORY SPACE I O SPACE INCREMENT PTR CONSTANT PTR TERMINATE ON TC INTERRUPT SOURCE SYNC HIGH PRIORITY RELATIVE TO CHANNEL 0 BYTE XFERS USE DRQ PIN FOR REQUEST SOURCE ARM CHANNEL MOV AX 1010001101100...

Страница 293: ...ROL AX 4 GET HIGH 4 BITS MOV BX AX SAVE ROTATED VALUE AND AX 0FFF0H GET SHIFTED LOW 4 NIBBLES ADD AX OFFSET WAVEFORM_DATA NOW LOW BYTES OF POINTER ARE IN AX ADC BX 0 ADD IN THE CARRY TO THE HIGH NIBB...

Страница 294: ...RRUPT SOURCE SYNCHRONIZE INTERNAL REQUESTS LOW PRIORITY RELATIVE TO CHANNEL 1 BYTE XFERS MOV AX 0001011101010110B MOV DX D0CON OUT DX AX NOW WE ASSUME THAT TIMER 2 HAS BEEN PROPERLY PROGRAMMED FOR A 2...

Страница 295: ...DIRECT MEMORY ACCESS UNIT 10 28...

Страница 296: ...11 Math Coprocessing...

Страница 297: ......

Страница 298: ...ithout dependence on programmed algorithms Overall math performance exceeds that afforded by a general purpose processor and software alone For the 80C186 Modular Core family the 80C187 math coprocess...

Страница 299: ...utes code written for the Intel387 DX and Intel387 SX math coprocessors The 80C187 conforms to ANSI IEEE Standard 754 1985 11 3 1 80C187 Instruction Set 80C187 instructions fall into six functional gr...

Страница 300: ...uare root instruction that executes faster than ordinary division Other arithmetic instruc tions perform exact modulo division round real numbers to integers and scale values by powers of two Table 11...

Страница 301: ...btraction FDIVR Divide real reversed FSUB Subtract real FDIVRP Divide real reversed and pop FSUBP Subtract real and pop FIDIVR Integer divide reversed FISUB Integer subtract Other Operations FSUBR Sub...

Страница 302: ...Use prologue code to reduce arguments to a range accepted by the instruction Use epilogue code to adjust the result to the range of the original arguments The transcendentals operate on the top one o...

Страница 303: ...p see Table 11 6 includes initialization excep tion handling and task switching instructions Table 11 5 80C187 Constant Instructions FLDZ Load 0 1 FLD1 Load 1 0 FLDPI Load FLDL2T Load log2 10 FLDL2E L...

Страница 304: ...bit floating point numeric value Temporary real is the native 80C187 format Figure 11 1 graphically represents these data types 11 4 MICROPROCESSOR AND COPROCESSOR OPERATION The 80C187 interfaces dir...

Страница 305: ...S 0 63 52 I Biased Exponent Significand S I 79 64 63 0 Biased Exponent Significand S X d 17 d 16 d 15 d 14 d 13 d 12 d 11 d 10 d 9 d 8 d 7 d 6 d 5 d 4 d 3 d 2 d 1 d 0 NOTES S Sign bit 0 positive 1 neg...

Страница 306: ...Modular Core Family 80C187 System Configuration ALE PEREQ RESET PEREQ EN 80C187 CKM NPS2 80C186 Modular Core Latch D15 0 External Oscillator CLKOUT RESOUT WR RD NCS ERROR NPS1 CLK NPWR NPRD BUSY BUSY...

Страница 307: ...each data transfer between memory and the 80C187 via the mi croprocessor takes at least 17 processor clocks The microprocessor cannot process any numerics ESC opcodes alone If the CPU encounters a nu...

Страница 308: ...187 access cannot activate NCS nu merics coprocessor select regardless of programming In a buffered system it is customary to place the 80C187 on the local bus Since DTR and DEN function normally duri...

Страница 309: ...tially Buffered Bus ALE PEREQ RESET PEREQ EN 80C187 CKM NPS2 80C186 Modular Core Latch D15 0 External Oscillator CLKOUT RESOUT WR RD CLK NPRD BUSY BUSY ERROR T OE D15 8 T OE Buffer Buffer A15 0 D7 0 E...

Страница 310: ...that result as if it is valid further compounding the original error Insert the FNOP in struction at the end of the 80C187 routine to force an ERROR check If the program is written in a high level la...

Страница 311: ...ia Processor Interrupt Pin INTx CLKOUT D15 0 CMD1 CMD0 PEREQ BUSY ALE A19 A16 AD15 0 RESET CKM NPS2 Q D Q D EN D15 0 A D D R E S S A19 0 A2 A1 80C187 RESOUT 80C186 Modular Core BUSY PEREQ 74 74 CLK La...

Страница 312: ...vel languages lib_80186 segment public code assume cs lib_80186 public _187_init _187_initproc far push bp save caller s bp mov bp sp get current top of stack cli disable maskable interrupts fninit in...

Страница 313: ...he computation are the coordinates x and y expressed as 32 bit reals NOTES This routine is coded for Intel ASM86 It is not set up as an HLL callable routine This code assumes that the 80C187 has alrea...

Страница 314: ...12 ONCE Mode...

Страница 315: ......

Страница 316: ...ard log ic and essentially take over operation of the board without removing the soldered device from the board 12 1 ENTERING LEAVING ONCE MODE Forcing UCS and LCS low while RESIN is asserted low enab...

Страница 317: ...2 Figure 12 1 Entering Leaving ONCE Mode RESIN UCS LCS All output bidirectional weakly held pins except OSCOUT NOTES 1 Entering ONCE Mode 2 Latching ONCE Mode 3 Leaving ONCE Mode assuming 2 occurred 1...

Страница 318: ...A 80C186 Instruction Set Additions and Extensions...

Страница 319: ......

Страница 320: ...struction set Data transfer instructions PUSHA POPA String instructions INS OUTS High level instructions ENTER LEAVE BOUND A 1 1 Data Transfer Instructions PUSHA POPA PUSHA push all and POPA pop all a...

Страница 321: ...reates the stack frame required by most block structured high level languages The first parameter size specifies the number of bytes of dynamic storage to be allocated for the procedure being entered...

Страница 322: ...edures C and B operate at the same lexical nesting level The following is a summary of the variable access for Figure A 2 1 Main has variables at fixed locations 2 Procedure A can access only the fixe...

Страница 323: ...t Level 1 After Main calls Procedure A ENTER creates a new display for Procedure A The first word points to the previous value of BP BPM The second word points to the current value of BP BPA BPM conta...

Страница 324: ...Figure A 5 After Procedure B calls Procedure C ENTER creates the display for Procedure C The first word of the display points to the previous value of BP BPB The second word points to the value of BP...

Страница 325: ...0C186 INSTRUCTION SET ADDITIONS AND EXTENSIONS A 6 Figure A 5 Stack Frame for Procedure B at Level 3 Called from A A1004 0A Old BP BP SP 15 0 BPM BPM BPM Display B Dynamic Storage B BPA BPM BPA BPA BP...

Страница 326: ...First LEAVE copies the current BP to the Stack Pointer releasing the stack space allocated to the current procedure Second LEAVE pops the old value of BP from the stack to return to the calling proce...

Страница 327: ...s of the two signed boundary values The lower limit word is at this address and the upper limit word immediately follows The limit values cannot be register operands if they are an invalid opcode exce...

Страница 328: ...ft arithmetic left shifts the destination operand left by an immediate value SAL has two operands The first destination is the effective address to be shifted The second count is an immediate byte val...

Страница 329: ...ificant bit of destination rotates into the most significant bit RCL destination count RCL immediate rotate through carry left rotates the destination byte or word left by an imme diate value RCL has...

Страница 330: ...B Input Synchronization...

Страница 331: ......

Страница 332: ...a stable state The data sheet specifies a setup and hold window larger than is actually required However variations in device operation e g temperature voltage require that a larger window be specifi...

Страница 333: ...by the actual size of the sampling window of the data latch and by the amount of time between the strobe sig nals of the two latches As the sampling window gets smaller the number of times an asynchr...

Страница 334: ...C Instruction Set Descriptions...

Страница 335: ......

Страница 336: ...ed must lie within 128 to 127 bytes of the first byte of the next instruction accum Register AX for word transfers AL for bytes port An I O port number specified as an immediate value of 0 255 or regi...

Страница 337: ...ster DI short label A label within the 128 to 127 bytes of the end of the instruction near label A label in current code segment far label A label in another code segment near proc A procedure in curr...

Страница 338: ...set maskable interrupts will cause the CPU to transfer control to an interrupt vector specified location OF Overflow Flag Set if the signed result cannot be expressed within the number of bits in the...

Страница 339: ...turned in AL and the remainder is returned in AH both high order half bytes are zeroed Instruction Operands none AL AH 0AH AL AH 0 AF CF DF IF OF PF SF TF ZF AAM ASCII Adjust for Multiply AAM Corrects...

Страница 340: ...tion operand with the result Both operands may be signed or unsigned binary numbers see AAA and DAA Since ADC incor porates a carry from a previous operation it can be used to write routines to add nu...

Страница 341: ...to the destination operand A bit in the result is set if both corre sponding bits of the original operands are set otherwise the bit is cleared Instruction Operands AND reg reg AND reg mem AND mem re...

Страница 342: ...procedure name Activates an out of line procedure saving information on the stack to permit a RET return instruction in the procedure to transfer control back to the instruction following the CALL Th...

Страница 343: ...rry right RCR instructions Instruction Operands none CF 0 AF CF DF IF OF PF SF TF ZF CLD Clear Direction flag CLD Zeroes the direction flag DF causing the string instructions to auto increment the sou...

Страница 344: ...erands none IF 0 AF CF DF IF OF PF SF TF ZF CMC Complement Carry Flag CMC Toggles complement carry flag CF to its opposite state and affects no other flags Instruction Operands none if CF 0 then CF 1...

Страница 345: ...word from the source byte or word The destination byte or word is addressed by the destination index DI register and the source byte or word is addresses by the source index SI register CMPS updates t...

Страница 346: ...F 1 if AL 9FH or CF 1 then AL AL 60H CF 1 AF CF DF IF OF PF SF TF ZF DAS Decimal Adjust for Subtraction DAS Corrects the result of a previous subtraction of two valid packed decimal operands the desti...

Страница 347: ...DEC reg DEC mem dest dest 1 AF CF DF IF OF PF SF TF ZF Table C 4 Instruction Set Continued Name Description Operation Flags Affected NOTE The three symbols used in the Flags Affected column are defin...

Страница 348: ...inder are undefined Nonintegral quotients are truncated to integers Instruction Operands DIV reg DIV mem When Source Operand is a Byte temp byte src if temp AX FFH then type 0 interrupt is generated S...

Страница 349: ...ZF ESC Escape ESC Provides a mechanism by which other processors coprocessors may receive their instructions from the 8086 or 8088 instruction stream and make use of the 8086 or 8088 addressing modes...

Страница 350: ...est on INTR if interrupts are enabled Instruction Operands none None AF CF DF IF OF PF SF TF ZF Table C 4 Instruction Set Continued Name Description Operation Flags Affected NOTE The three symbols use...

Страница 351: ...e 0 interrupt is generated In particular this occurs if division by 0 is attempted Nonintegral quotients are truncated toward 0 to integers and the remainder has the same sign as the dividend Instruct...

Страница 352: ...is a Word DX AX word src AX if DX sign extension of AX then CF 0 else CF 1 OF CF AF CF DF IF OF PF SF TF ZF IN Input Byte or Word IN accum port Transfers a byte or a word from an input port to the AL...

Страница 353: ...cannot be overridden After the data transfer takes place the DI register increments or decrements depending on the value of the direction flag DF The DI register changes by 1 for byte transfers or 2 f...

Страница 354: ...eplaces CS SP again is decremented by two and IP is pushed onto the stack and is replaced by the first word of the interrupt pointer If interrupt type 3 the assembler generates a short 1 byte form of...

Страница 355: ...P CS and the flags from the stack IRET thus affects all flags by restoring them to previously saved values IRET is used to exit any interrupt procedure whether activated by hardware or software Instru...

Страница 356: ...ot Above JBE disp8 JNA disp8 Transfers control to the target location if the tested condition C 1 or ZF 1 is true Instruction Operands JBE short label JNA short label if CF 1 or ZF 1 then IP IP disp8...

Страница 357: ...8 Transfers control to the target location if the condition tested SF OF and ZF 0 is true Instruction Operands JG short label JNLE short label if SF OF and ZF 0 then IP IP disp8 sign ext to 16 bits AF...

Страница 358: ...TF ZF JMP Jump Unconditionally JMP target Transfers control to the target location Instruction Operands JMP short label JMP near label JMP far label JMP memptr JMP regptr if Inter segment then CS SEG...

Страница 359: ...location if the tested condition SF 0 is true Instruction Operands JNS short label if SF 0 then IP IP disp8 sign ext to 16 bits AF CF DF IF OF PF SF TF ZF JNP JPO Jump on Not Parity Jump on Parity Od...

Страница 360: ...tion Format JS short label if SF 1 then IP IP disp8 sign ext to 16 bits AF CF DF IF OF PF SF TF ZF LAHF Load Register AH From Flags LAHF Copies SF ZF AF PF and CF the 8080 8085 flags into bits 7 6 4 2...

Страница 361: ...eave LEAVE Reverses the action of the most recent ENTER instruction Collapses the last stack frame created First LEAVE copies the current BP to the stack pointer releasing the stack space allocated to...

Страница 362: ...mode to assert its bus LOCK signal while the following instruction executes The instruction most useful in this context is an exchange register with memory The LOCK prefix may be combined with the seg...

Страница 363: ...f CX is not 0 otherwise the instruction following LOOP is executed Instruction Operands LOOP short label CX CX 1 if CX 0 then IP IP disp8 sign ext to 16 bits AF CF DF IF OF PF SF TF ZF LOOPE LOOPZ Loo...

Страница 364: ...sfers a byte or a word from the source operand to the destination operand Instruction Operands MOV mem accum MOV accum mem MOV reg reg MOV reg mem MOV mem reg MOV reg immed MOV mem immed MOV seg reg r...

Страница 365: ...urce operand is a word then it is multiplied by register AX and the double length result is returned in registers DX and AX The operands are treated as unsigned binary numbers see AAM If the upper hal...

Страница 366: ...dest dest 1 affecting flags AF CF DF IF OF PF SF TF ZF NOP No Operation NOP Causes the CPU to do nothing Instruction Operands none None AF CF DF IF OF PF SF TF ZF NOT Logical Not NOT dest Inverts the...

Страница 367: ...AX register respec tively to an output port The port number may be specified either with an immediate byte constant allowing access to ports numbered 0 through 255 or with a number previously placed i...

Страница 368: ...tion Operands OUTS port src_string OUTS repeat port src_string dst src AF CF DF IF OF PF SF TF ZF POP Pop POP dest Transfers the word at the current top of stack pointed to by SP to the destination op...

Страница 369: ...then incremented by two to point to the new top of stack Instruction Operands none Flags SP 1 SP SP SP 2 AF CF DF IF OF PF SF TF ZF PUSH Push PUSH src Decrements SP by two and then transfers a word fr...

Страница 370: ...P 2 SP 1 SP SI SP SP 2 SP 1 SP DI AF CF DF IF OF PF SF TF ZF PUSHF Push Flags PUSHF Decrements SP by two and then transfers all flags to the word at the top of stack pointed to by SP Instruction Opera...

Страница 371: ...ined AF CF DF IF OF PF SF TF ZF RCR Rotate Through Carry Right RCR dest count Operates exactly like RCL except that the bits are rotated right instead of left Instruction Operands RCR reg n RCR mem n...

Страница 372: ...n REPNE and REPNZ are mnemonics for the same prefix byte These instructions function the same as REPE and REPZ except that the zero flag must be cleared or the repetition is terminated ZF does not nee...

Страница 373: ...T immed8 IP SP 1 SP SP SP 2 if inter segment then CS SP 1 SP SP SP 2 if add immed8 to SP then SP SP data AF CF DF IF OF PF SF TF ZF ROL Rotate Left ROL dest count Rotates the destination byte or word...

Страница 374: ...efined AF CF DF IF OF PF SF TF ZF SAHF Store Register AH Into Flags SAHF Transfers bits 7 6 4 2 and 0 from register AH into SF ZF AF PF and CF respectively replacing whatever values these flags previo...

Страница 375: ...al value Note that SAR does not produce the same result as the dividend of an equivalent IDIV instruction if the destination operand is negative and 1 bits are shifted out For example shifting 5 right...

Страница 376: ...ds SBB reg reg SBB reg mem SBB mem reg SBB accum immed SBB reg immed SBB mem immed if CF 1 then dest dest src 1 else dest dest src AF CF DF IF OF PF SF TF ZF Table C 4 Instruction Set Continued Name D...

Страница 377: ...eparture from a given value If SCAS is prefixed with REPNE or REPNZ the operation is interpreted as scan while not end of string CX not 0 and string element is not equal to scan value ZF 0 Instruction...

Страница 378: ...then OF 1 else OF 0 else OF undefined AF CF DF IF OF PF SF TF ZF STC Set Carry Flag STC Sets CF to 1 Instruction Operands none CF 1 AF CF DF IF OF PF SF TF ZF STD Set Direction Flag STD Sets DF to 1 c...

Страница 379: ...pdates DI to point to the next location in the string As a repeated operation Instruction Operands STOS dest string STOS repeat dest string When Source Operand is a Byte DEST AL if DF 0 then DI DI DEL...

Страница 380: ...but does not return the result i e neither operand is changed If a TEST instruction is followed by a JNZ jump if not zero instruction the jump will be taken if there are any corresponding one bits in...

Страница 381: ...semaphore that controls access to a resource shared by multiple processors Instruction Operands XCHG accum reg XCHG mem reg XCHG reg reg temp dest dest src src temp AF CF DF IF OF PF SF TF ZF Table C...

Страница 382: ...tion Operands XLAT src table AL BX AL AF CF DF IF OF PF SF TF ZF XOR Exclusive Or XOR dest src Performs the logical exclusive or of the two operands and returns the result to the destination operand A...

Страница 383: ...INSTRUCTION SET DESCRIPTIONS C 48...

Страница 384: ...D Instruction Set Opcodes and Clock Cycles...

Страница 385: ......

Страница 386: ...A Calculation mod Effect on EA Calculation 0 0 0 BX SI DISP 0 0 if r m 110 DISP 0 disp low and disp high are absent 0 0 1 BX DI DISP 0 0 if r m 110 EA disp high disp low 0 1 0 BP SI DISP 0 1 DISP disp...

Страница 387: ...10 segment register 0 0 0 reg 1 1 0 9 immediate 0 1 1 0 1 0 s 0 data data if s 0 10 POP Pop memory 1 0 0 0 1 1 1 1 mod 000 r m 20 register 0 1 0 1 1 reg 10 segment register 0 0 0 reg 1 1 1 reg 01 8 P...

Страница 388: ...if sw 01 4 16 immediate to accumulator 0 0 0 0 0 1 0 w data data if w 1 3 4 1 ADC Add with carry reg memory with register to either 0 0 0 1 0 0 d w mod reg r m 3 10 immediate to register memory 1 0 0...

Страница 389: ...0 immediate with register memory 1 0 0 0 0 0 s w mod 111 r m data data if sw 01 3 10 immediate with accumulator 0 0 1 1 1 1 0 w data data if w 1 3 4 1 AAS ASCII adjust for subtraction 0 0 1 1 1 1 1 1...

Страница 390: ...m data data if w 1 4 16 immediate to accumulator 0 0 1 0 0 1 0 w data data if w 1 3 4 1 OR Or reg memory and register to either 0 0 0 0 1 0 d w mod reg r m 3 10 immediate to register memory 1 0 0 0 0...

Страница 391: ...LODS Load byte word to AL AX 1 0 1 0 1 1 0 w 12 STOS Store byte word from AL AX 1 0 1 0 1 0 1 w 10 Repeated by count in CX MOVS Move byte word 1 1 1 1 0 0 1 0 1 0 1 0 0 1 0 w 8 8n INS Input byte word...

Страница 392: ...1 0 0 1 1 disp 4 13 2 JNC not carry 0 1 1 1 0 0 1 1 disp 4 13 2 JNBE JA not below or equal above 0 1 1 1 0 1 1 1 disp 4 13 2 JNP JPO not parity parity odd 0 1 1 1 1 0 1 1 disp 4 13 2 JNO not overflow...

Страница 393: ...1 1 0 0 0 1 0 disp 6 16 2 LOOPZ LOOPE Loop while zero equal 1 1 1 0 0 0 0 1 disp 5 16 2 LOOPNZ LOOPNE Loop while not zero not equal 1 1 1 0 0 0 0 0 disp 5 16 2 JCXZ Jump if CX zero 1 1 1 0 0 0 1 1 dis...

Страница 394: ...ytes 3 6 ASM 86 Instruction Format Hex Binary 00 0000 0000 mod reg r m disp lo disp hi add reg8 mem8 reg8 01 0000 0001 mod reg r m disp lo disp hi add reg16 mem16 reg16 02 0000 0010 mod reg r m disp l...

Страница 395: ...eg r m disp lo disp hi sbb reg8 reg8 mem8 1B 0001 1011 mod reg r m disp lo disp hi sbb reg16 reg16 mem16 1C 0001 1100 data 8 sbb AL immed8 1D 0001 1101 data lo data hi sbb AX immed16 1E 0001 1110 push...

Страница 396: ...hi xor reg16 mem16 reg16 3A 0011 1010 mod reg r m disp lo disp hi xor reg8 reg8 mem8 3B 0011 1011 mod reg r m disp lo disp hi xor reg16 reg16 mem16 3C 0011 1100 data 8 xor AL immed8 3D 0011 1101 data...

Страница 397: ...m data lo data hi imul immed16 70 0111 0000 IP inc 8 jo short label 71 0111 0001 IP inc 8 jno short label 72 0111 0010 IP inc 8 jb jnae jc short label 73 0111 0011 IP inc 8 jnb jae jnc short label 74...

Страница 398: ...disp lo disp hi data lo data hi sub reg16 mem16 immed16 mod 110 r m disp lo disp hi data lo data hi xor reg16 mem16 immed16 mod 111 r m disp lo disp hi data lo data hi cmp reg16 mem16 immed16 82 1000...

Страница 399: ...1001 0010 xchg AX DX 93 1001 0011 xchg AX BX 94 1001 0100 xchg AX SP 95 1001 0101 xchg AX BP 96 1001 0110 xchg AX SI 97 1001 0111 xchg AX DI 98 1001 1000 cbw 99 1001 1001 cwd 9A 1001 1010 disp lo dis...

Страница 400: ...100 data lo data hi mov SP immed16 BD 1011 1101 data lo data hi mov BP immed16 BE 1011 1110 data lo data hi mov SI immed16 BF 1011 1111 data lo data hi mov DI immed16 C0 1100 0000 mod 000 r m data 8 r...

Страница 401: ...1 r m mod 100 r m mod 101 r m mod 110 r m mod 111 r m C8 1100 1000 data lo data hi level enter immed16 immed8 C9 1100 1001 leave CA 1100 1010 data lo data hi ret immed16 intersegment CB 1100 1011 ret...

Страница 402: ...m disp lo disp hi ror reg16 mem16 CL mod 010 r m disp lo disp hi rcl reg16 mem16 CL mod 011 r m disp lo disp hi rcr reg16 mem16 CL mod 100 r m disp lo disp hi sal shl reg16 mem16 CL mod 101 r m disp...

Страница 403: ...p repe repz F4 1111 0100 hlt F5 1111 0101 cmc F6 1111 0110 mod 000 r m disp lo disp hi data 8 test reg8 mem8 immed8 mod 001 r m mod 010 r m disp lo disp hi not reg8 mem8 mod 011 r m disp lo disp hi ne...

Страница 404: ...mod 110 r m mod 111 r m FF 1111 1111 mod 000 r m disp lo disp hi inc mem16 mod 001 r m disp lo disp hi dec mem16 mod 010 r m disp lo disp hi call reg16 mem16 intrasegment mod 011 r m disp lo disp hi c...

Страница 405: ...H SP PUSH BP PUSH SI PUSH DI 6x PUSHA POPA BOUND w f r m 7x JO JNO JB JNAE JC JNB JAE JNC JE JZ JNE JNZ JBE JNA JNBE JA 8x Immed b r m Immed w r m Immed b r m Immed is r m TEST b r m TEST w r m XCHG b...

Страница 406: ...BX POP SP POP BP POP SI POP DI 5x PUSH w i IMUL w i PUSH b i IMUL w i INS b INS w OUTS b OUTS w 6x JS JNS JP JPE JNP JPO JL JNGE JNL JGE JLE JNG JNLE JG 7x MOV b f r m MOV w f r m MOV b t r m MOV w t...

Страница 407: ...PU register is immediate byte sign extended si short intrasegment w word operation i immediate l long intersegment sr segment register z zero Byte 2 Immed Shift Grp1 Grp2 mod 000 r m ADD ROL TEST INC...

Страница 408: ...Index...

Страница 409: ......

Страница 410: ...es Data transfers Address bus See Address and data bus Address space See Memory space I O space Addressing modes 2 27 2 36 and string instructions 2 34 based 2 30 2 31 2 32 based index 2 34 2 35 direc...

Страница 411: ...5 2 30 C Carry Flag CF 2 7 2 9 Chip Select Unit CSU 6 1 and DMA 10 8 and DMA acknowledge signal 10 22 and HALT bus cycles 3 28 and READY 6 15 6 16 and wait states 6 15 6 16 block diagram 6 3 bus cycle...

Страница 412: ...ransfers 10 20 synchronization 10 18 transfer count 10 18 10 19 programming pointers 10 10 10 14 requests 10 3 external 10 4 internal 10 6 software 10 6 Timer 2 10 6 selecting source 10 17 synchroniza...

Страница 413: ...ulation instructions 2 21 2 22 A 9 data transfer instructions 2 18 2 20 A 1 A 8 data types 2 37 2 38 enhancements A 8 high level instructions A 2 nesting A 2 processor control instructions 2 27 progra...

Страница 414: ...s hold protocol Direct Memory Access DMA Unit Interrupts LEAVE instruction A 7 Literature ordering 1 6 Local bus 3 1 3 41 11 11 Long integer defined 11 7 Long real defined 11 7 M Manuals online 1 5 Ma...

Страница 415: ...k register 8 17 8 18 8 28 Processor control instructions 2 27 Processor Status Word PSW 2 1 2 7 2 41 bits defined 2 7 2 9 flag storage formats 2 19 reset status 2 7 Program transfer instructions 2 23...

Страница 416: ...cation 2 13 2 14 interrupts 2 45 overview 2 17 See also Addressing modes Instruction set Square wave generator code example 9 17 9 22 SRDY See READY SS register 2 1 2 5 2 6 2 13 2 15 2 30 2 45 Stack f...

Страница 417: ...e output 9 14 9 15 Timer Maxcount Compare Registers TxCMPA TxCMPB 9 11 Timers See Timer Counter Unit TCU Trap exceptions 2 43 Trap Flag TF 2 7 2 9 2 43 2 48 T state and bus cycles 3 9 and CLKOUT 3 8 d...

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