13

1280x8638259A

13.1 13.1.1

13.1.2

CPUCPU

1. CPUINTA2. IPCS

3. CPU4. ()

5. 6.

633()

PSW

13.1.3 1. CPUpriority

PC8259A1 13.1INTRCPU

13.1

CPU 13.2

13.2

(2) CPUINTA13.3(a)

13.3 (a)

13.3 (b) ()INTR

2. CPUCPU13.4

13.4 STIIRETSTIIRET............

13.2 80x8613.2.1 13.5

13.5 80x86INT n INT 3INTO, OF=1(TF=18259ANMIINTRIRQ0....IRQ7

80386CPU interrupt),exception) 8086256 (fault) (trap) (abort)

INT n

13.2.2 interrupt vector4:(IP)(CS)

80x862561K25680x8600000H003FFH1K13.6

13.6 25532312245

4

3

2

1

02750000: 03FFH

0000:007FH0000:007EH

0000:0014H0000:0013H

0000:0010H0000:000FH

0000:000CH0000:000BH

0000:0008H0000:0007H

0000:0004H0000:0003H

0000:0000H0

025527H0000H009CH413.727H8765H:4321H

13.7 87H

65H

43H

21H0000:009FH

0000:009CH

4CPUN244N(4)IP IP (4N, 4N+1) CS : CS (4N+2, 4N+3)

N1N

13.1 313.8

13.8

13.2 20H00000080H4400000080H= 10H00000081H= 20H00000082H= 30H00000083H= 40H:

13.3 17H2340H:7890H4: 17H40000:005CH0000:005DH0000:005EH0000:005FH4

13.2.3 ,80x86 CPUNMIINTR1. NMIIF208H09H0AH0BH4

2. CPUINTRCPUIF1CPU

8086

13.9 8086T1 T2 T3 T4 TI TI TI T1 T2 T3 T4CLK____INTAAD7~AD0

13.2.4 CPUINT n(INT 3)INTOINT n

(1) INT n 80x86INT nnCPU(2) 0DIV IDIV 0CPU0

(3) 4OF1INTO4CPUOF=0INTOINTO INTO13-1

13-1............

OVERFLOW: PUSH AX PUSH BX PUSH CX PUSH DXADD AX , BX; OF=1 INTO

POP DXPOP CXPOP BXPOP AX IRET

(4) 1CPUTF1CPUCPU1 1CPU

(5) (3)

INT nINT 3

13.10 ADD AL, BLJMP 201HINC ALCMP AL, 0FFHJL 200H1FCH,1FDH1FEH,1FFH200H201H,202H203H,204H

(1) CPUINT nINTA(2) TF10(3)

13.2.5 1.

13.11

13.11 INTR ____ INTA

IPCSPSW(FR)CPU Q

INTRCPUN

IPCS

IPCSPSW

.....STI...IRET

...164N4N+2IFTFPSWCSIPIRETIPCSPSWCPUCSIP

2. 80x86 80x8613.12

13.12 80x8680x86INTO,INT n?NMIINTR?TF=1?NNNNTF=1?NYYYYYNNTEMPTFIFTFCSIP(4N4N+1)IP(4N+2,4N+3)CSIPCSNMITEMP=1?YYNNIRET

INT nINTONMIINTR

IF=1IF 1STI

13.12()

IF=1TF=1

DIVIDIV

FR->,TF->IF,TFCS,IP->(0,1)->IP(2,3)->CS

FR->,TF->IF,TFCS,IP->(4,5)->IP(6,7)->CS

,IRET,CS,IP,FR

01H

IRETCSIPFR

5040H:7060H

2010H:4030H

00H

....

60704050(FR)30401020(FR)

13.3 8259A (8259A Programmable Interrupt Controller-PIC) Intel 8259A80x86

8259A86498259A

.

13.3.1 8259A2828pin DIP), DIP:Dual-In-line Package ,13.13

Chip Select)CPU8259A CPU 8259ACPU CPU 8259ACPU

D7~ D0 :D7~ D0 IR7~IR0 :INTCPUINTACPU

A08259ACAS2~ CAS0:CASCADELINES3:/8259A1 8259A0P46213.158286 *8259A8259AICW4

13.3.2 8259A8259A13.14

13.14 8259A

CPUAD7~AD0INTRISRICW1 OCW1 (IMR)ICW2OCW2ICW3OCW3ICW4PRIRRD7~D0

...INTA0CAS0CAS1CAS2...

IR7IR0 8259A

IRRInterrupt Request RegisterPR---Priority ResolverISR---In-Service RegisterIMR---Interrupt Mask RegisterICWs---Initialization Command WordsOCWs---Operation Command Words7CPUICW1 ~ICW4---OCW1~OCW3(). The OCWs can be written into the 8259A anytime after initialization.(P6P7

7: A0

8259AIRR8IR0IR7ISRPR

IR0IR7->IRR1->IMR(=1=0)->PR->PR->CPUCPUIF=1CPU (P463 13.16)

13.9 8086T1 T2 T3 T4 TI TI TI T1 T2 T3 T4CLK____INTAAD7~AD0

8259AIRRIR0IR7IRR()ISR1IRR8259A(ICW2)D7D0ICW4AEOI1 ISR 1()(EOI)

13.3.3 8259A1. (1) (FULLY NESTED MODE)IRiIR0()>IR7().This mode is entered after initialization unless another mode is programmed.

ISRISn18259A()CPU(EOI)1

(2) (SPECIAL FULLY NESTED MODESFNM)8259ICW4SFNM(p464)

(3) (AUTOMATIC ROTATION)()IR0->IR7IR0IR0IR1IR2IR3IR4 IR5 IR6 IR7IR0IR4IR4__________________________________OCW2( p466)

IR0

IR1

IR2

IR3

IR4

IR5

IR6

IR7

(4)(SPECIFIC ROTATION)IR4IR5

2. ()(IMR)1OCW1IMR1*(SPECIAL MASK MODE)P462

3. (END OF INTERRUPTEOI)(1)(AUTOMATICAEOI) ISRAEOIISR08259AIF1()CPU

AEOIICW4AEOI(AEOI=1)

(2)()8259A(OCW2:EOI=1,SL=0,R=0)MOV AL,20H; OCW2=20H OUT 20H,AL; =20H()ISR10IR0IR7

10111

(3)(SPECIFIC EOISEOI)()ISR()EOISEOIOCW2:EOI=1,SL=1,R=0,L2L0.L2L0ISR

4. IRi

IRi

ICW1LTIM

5. (ICW4BUF=1)8259A(8286)8259A ( )ICW4M/S()8259A(ICW4BUF=0)8259A8259A ( ) 8259AICW4BUF0M/S

(Polling)8259ACPUCPUIF=0(CPU)CPU8259A(poll command)OCW3:P

00001100

(IN)

8259AP=1 ISR1 CPUAL

13.3.5 8259A8259AICWICW4OCWOCW38259A(A0 = 0)(A0 = 1)8259A

1. 8259AICWICW4 4(1) ICW1ICW1 (A0 = 0)D4 1ICW OCW1 OCW1 D4 0ICW

ICW1

IC4 ICW4IC4 = 0ICW4IC4 = 1ICW4SNGL8259ASNGL=0ICW3 SNGL=1ICW3ADI8085CALL80x86LTIMLTIM=0LTIM=1A5A7 808580x86

(2) ICWICW2 (A0 = 1)ICWICW

A15/T7A14/T6A13/T5A12/T4A11/T3A10A9A81ICW2A0 D7 D6 D5 D4 D3 D2 D1 D0 ICW2

80x86ICWD7D3N5T7T33D2D0;80x86ICW88A15A8

80x868259ACPU8N5D7D3T7T3ICW3D2D08259AIR0IR7000111

: ICW2 28H , CPU IR2AH IR

(3) ICWICW

ICW3

8259AICW IRi 8259A8259AS10

IR2IR6 8259AIR8259AICW 01000100

8259AICW ID2ID0 8259A8259AIR

IR0IR7 ID000111

8259A8259AIR6 8259AICW ID2=1ID1=1ID0=0

(4) ICW480x86ICW4

ICW4

PMPM = 08080/8085PM = 180x86AEOIAEOI=0EOIAEOI=1EOIBUF8259ABUF=1BUF=0

SP/ENM/S8259A8259A8259A8259A()M/S8259AM/S=0M/S=1(BUF=0)M/SSFNMSFNM=0SFNM=1

8259A8259AICWCPUA0

8259A13.17

ICWICW

ICWSNGL=0ICWICW

ICWIC4=1ICW480x86ICW4

8259A80x86 CPUICWICWICW4

ICWICWICWICW4

8259AOCW

2. 8259A8259AICWICW4OCW1OCW3 8259A

(1) OCW1OCW1 8259A(A0=1)OCW1 IMR

OCW1

M0M7 8259AIR0IR7OCW1 Mi 1IRi

OCW111110000IR7IR4IR3IR0

(2) OCW2OCW2 (A0=0)OCW2

OCW2

DD= 00OCW2 RR1R0SLOCW2 L2L1L0 SL1SL0EOIEOI1ISR0ICW4 AEOI0ISR1

L2L1L0 SL=1RSLEOIL2L1L0 8000111IR0IR7 RSLEOIRSLEOI13-2

13-2 RSLEOI

RSLEOI001EOI011EOI101EOI111EOI000EOI100EOI110010

(3) OCW3OCW3 (A0=0)

OCW3

D D = 01OCW ESMMSMMESMM0SMMESMM1SMMESMM=1SMM=08259AESMM=SMM=18259A

P(Poll Command)P=18259A

8259A13.6 8259A(1) 80x868259A

(2) 08HIR0IR 08H0FH

(3)

8259A20H21H

MOV AL13H ICW18259AICW4OUT 20HAL MOV AL08H ICW208HOUT 21HAL MOV AL0DH ICW480x86EOIOUT 21HAL

8259AOCW2=20HMOV AL20H OCW2EOIOUT 20HAL

8259A

8259A: ()P=1OCW3(IN AL,20H)

IRROCW3(RR=1,RIS=0)(IN AL,20H)

ISR:OCW3(RR=1,RIS=1)(IN AL,20H)

IMR (IN AL,21H)

1IN AL21H IMRAND AL7FH IR7OUT 21HAL

2IN AL21H IMR

OR AL80H IR7

OUT 21HAL

13.3.6 8259A 1. 8259A IBM PC/XT IBM PC/XT 8259A 813.1813-3

13.18 8259AIBM PC/XT

2. 8259A IBM PC/AT IBM PC/XT 7INT 0AH802878 8259A8259AIBM PC/XT8259A8259AINT8259AIR2(PC/XT)CAS0CAS28259ACAS0CAS2 8259ACAS0CAS2

IBM PC/AT 28259A13.19:

IRQ0>IRQ1>IRQ8>IRQ9>IRQ10IRQ15>IRQ3>IRQ4>IRQ5>IRQ6>IRQ7

13.19 8259A IBM PC/AT

(1)ALDS:DX AH=25H INT 21H AL= DS:DX=(2)ALES:BX AH=35H INT 21H AL=

ES:BX=

DOS

MOV AL,N; type N InterruptMOV AH,35H; get Interrupt vectorINT 21H;PUSH ES; save the old base andPUSH BX; offset of interrupt NPUSH DS;MOV AX,SEG INTHAND;MOV DS,AX; base of INTHAND in DSMOV DX, Offset INTHAND; offset in DXMOV AL, N;MOV AH, 25H; Set Interrupt VectorINT 21H;POP DS;

POP DX; restore the old offsetPOP DS;and base of interruptMOV AL,N;MOV AH,25H;set interrupt vectorINT 21H;RET ;return

INTHAND:. Interrupt Processing RoutineIRET

DATA SEGMENT MESS DB `THIS IS A IRQ7 INTRUPT !`,0AH,0DH,`$`DATA ENDSCODE SEGMENT ASSUME CS:CODE,DS:DATASTART: MOV AX, CS MOV DS, AX ;set up ds to same as cs MOV DX,OFFSET INT7 MOV AX, 250AH INT 21H IN AL, 21H AND AL, 7FH OUT 21H, AL MOV CX, 10 STIHERE: JMP HERE

INT7: MOV AX,DATA MOV DS,AX MOV DX,OFFSET MESS MOV AH,09 INT 21H MOV AL,20H OUT 20H,AL LOOP NEXT IN AL,21H OR AL,80H OUT 21H,AL STI MOV AH,4CH INT 21H NEXT: IRET CODE ENDS END START

13 1. (TF=1)INTR4030H:2080HINTR9080H:3020H.P475 7P475 8 (0BH 0FH)