80C51 4.1I/O4.1.1 P14.1.2 P34.1.3 P24.1.4 P04.2/4.2.14.2.2/T0T1

80C51 4.2.3/T24.2.44.2.5/4.34.44.4.14.4.24.4.3

80C51 14234

80C51 4.1 I/O 80C51832/I/O4--1

41 80C51I/O

I/OP0P1P2P38888I/OI/OI/OI/OSFR80H90HA0HB0H80H~87H90H~97HA0H~A7HB0H~B7H8TTL4TTL4TTL4TTL

I/O P0P1P2P3

88CTC2T2 T2EX(CTC280C52) 8RXD TXDINT0 INT1CTC01 T0 T1WR RD

80C51 4.1.1 P1 P18,,90H,90H~97H P14--1:BUF1BUF2 FETQ0/

80C51

4---1 P1

80C51 P1 P1.i:CPU0,D=0Q=0Q=1Q0A0CPU1D=1Q=1 Q =0Q0A1 P1.i:P1.iAP1.i1ABUF1B0ABUF1B

80C51 2 P1 ,; ,,,1; ,

80C51 A1AAAQ0Q0 P14TTL

80C51 3 P1CPUP18(), MOV P1,A ;(P1) (A) MOV P1,#data ;(P1)#data MOV P1, direct ;(P1)(direct) MOV A ,P1 ;(A)(P1) MOV direct,P1 ;(direct)(P1)

80C51 SETB P1.i ;P1.i1 CLR P1.i ;P1.i0 MOV P1.i,C ;P1.iCY MOV C, P1. i ;CY P1. I JB P1.i ,rel ;P1.i=1, JBC P1.i ,rel ;P1.i=0,P1.i0 ANL C, P1.i ;CY( P1.iCY) ORL C, P1.i ;CY( P1.i+CY) P1.ii=07

80C51 P18 ORL P1,#0000,0010BP1.11, ANL P1,#1111,1101BP1.10, P1

80C51 CPUBUF11A MOV A,P1 ;(A)(P1) MOV direct,P1 ;(direct)(P1)

80C51 CPUBUF2-- ANLORLXRLJBCCPLMOVSETBCLR

80C51 ,P1.iP1.i1CPU01

80C51 4 S6P2P1P2P1

80C51 S6P2P1S1P15 P1 80C52P1.0P1.1I/O

80C51 P1.0/2T2; P1.1/2T2EX P3 P1.0P1.1/2

80C51 4.1.2 P3 P38,,B0H,B0H~B7H1 P3 4---2P3P1

80C51

4--2P3

80C51 P3QFETQ0 QQ I/O

80C51 (2) B1P3.iP1 P3I/O

80C51 1P3.i0C1B01Q0A011Q0A P3

80C51 1 P3I/O1

80C51 2 P3 P1P3I/O,P18 :P3.0RXD

80C51 P3.2INT0 0P3.3INT1 1P3.4T0 /0P3.5T1 /1:

80C51 P3.1TXD P3.6WR P3.7RD (3) P34TTL

80C51 4.1.3 P2 P28,,A0H,A0H~A7H1 P24--3

4---3P280C51

80C51 P1 P2 QPCDPTRFET Q0 QQ

80C51

4---3P2

80C51 (2) C 0Q01Q0A01Q10Q0A1 P2I/O

80C51 BA0110 P28

80C51 2 P2 P2(1)I/OP2P1(2) P28P01664 KB8I/O(3) P24TTL

80C51 3 P2(1)P28(2) P2P2I/O(3) P2

80C51 256 BMOVX A@RiMOVX @RiAP2P2I/O 256 B MOVX A@DPTRMOVX @DPTRAP28P28P2

80C51 P2I/O P1P3P2P2I/OMOVX A@RiMOVX @RiA

80C51 4.1.4 P0 P08,,80H,80H~87H1 P04--4

80C51

44 P0

80C51 P0P1 P0/FET Q0 P0P1P0/

80C51 (2) 1/ /11FET/0FETA/1

80C51 /00FET/1FETA/0

80C51 /P0/FETP0

80C51 0 0FETP0 FETP0 P0P0i10FETP0iP0.i01FETP0.i

80C51 P0P0.iP0i1FETP0.iACPUP02 P0(1)I/O 1

80C51 P1NMOS(2)/ P0 ///88P0/I/O

80C51 P0/I/O

(3) P08TTL

80C51 4.2/4.2.1 /timer/counterCPU 80C5116//T0/T180C5216//T0/T1/T280C5180C5528T3

80C51 /1 T0T1T2101

80C51 4.2.2/T0T11 /T0T1/T0T14--5 /T0T1 TH0TL0TH1TL1 TMODTCON T0T1INT0INT1

80C51

4---5 /T0T1

80C51 2 /T0T1(1)/T0T1TMODTMOD889H D7 D6 D5 D4 D3 D2 D1 D0

GATEC/TM1M0GATEC/TM1M0

80C51 4/T04/T1GATEGATE=1INT0INT1TR0TR1INT0TR0T0INT1TR1T1 GATE=0TR0TR1T0T1

80C51 C/TC/T =1C/T=0M1M0 M1M04--2

80C51

4--2/T0 T1

M1M0 00013011 161028113T08T1

80C51 /T0T1TMOD 4--34--3TMOD

80C51

D7GATE/T1D6C/T/T1C/T=1C/T=0D5M1/T1D4M0/T1D3GATE/T0D2C/T/T0C/T=1C/T=0D1M1/T0D0M0/T0

80C51 (2) /T0T1TCON TCON888H88H~8FH

8FH8EH8DH8CH8BH8AH89H88HTF1TR1TF0TR0IE1IT1IE0IT0

80C51 TF1TCON.7/T1/T100

80C51 TR1TCON.6/T11T10T1 TF0TCON.5/T0TF1 TR0TCON.4/T01T00T0

80C51 IE1TCON.31 IT1TCON.21 IE0TCON.10 IT0TCON.00 TCON4

80C51 TCON0/T0T1TCON4--4

80C51 4---4TCON

D7 TF1(TCON.7)T1D6TR1TCON.6/T1D5TF0 TCON.5/T0D4TR0TCON.4/T0D3IE1TCON.31D2IT1TCON.21D1IE0TCON.10D0IT0TCON.00

80C51 (3) /T0T1TH1TL1TH0TL0 /T0T116,88// 4---5

80C51 3 /T0T1 /T0T1TMODC/T(1) C/T=01121/1212 MHz1 MHz

80C51 4--5/T0T1

TH1T188DHTL1T188BHTH0T088CHTL0T088AH

80C51 (2) C/T=1 T0P3.4T1(P3.5) S5P2CPU101S3P1101/24

80C51 4 /T0T1 M1M0/T0T1/T0T1012310 TMODM1=0M0=0004--613TLx3

80C51

4---6 0/T0T1

80C51 TLx5THxTHxTFxCPU GATE=0A//TRxTRx=1/TRx=0/ GATE=1AINTxBTRxINTx//TRxINTx

80C51 TFxCPUTFxTFx(2) 1 TMODM1=0M0=1114--716

80C51

4--7 1/T0T1

80C51 TLxTHxTHxTFxCPU0(3) 2 TMODM1=1M0=02168824--8

80C51

4--8 2/T0T1

80C51 2TLx8THx8 TLxTFxCPUTHxTLx THx 2

80C51 (4) 3 TMODM1=1M0=13/T08/8TL08/TH083/T04--9

80C51

4---93/T0

80C51

/08TL0T0GATEINT0TR0T0TH0T0/TL0/T1/TR1TF1

80C51 3/T14--10/T1012/T1/T03

80C51

4--103/T1

80C51 4.2.3 /T2 80C52/T216//T28TL2TH2T2CONT2MODRCAP2LRCAP2H/T2:T2(P1.0)

80C51 T2(P1.0)T2EX(P1.1)1 /T21T2CON T2CON80C8H0C8H~0CFH

80C51 :TF2(T2CON.7)/T2T2RCLK=lTCLK=lTF2

0CFH0CEH0CDH0CCH0CBH0CAH0C9H0C8HTF2EXF2RCLKTCLKEXEN2TR2C/T2CP/RL2

80C51 EXF2(T2CON.6)/T2EXEN2=1T2EX,EXF2/T2CPUEXF2 RCLK(T2CON.5)/T2T1RCLK=l/T2;RCLK=0/T1

80C51 TCLK(T2CON.4)/T2T1TCLK=l/T2;TCLK=0/Tl

80C51 EXEN2(T2CON.3)/T2EXEN2=1/T2T2EX/T2EXF21EXEN2=0T2EXTR2(T2CON.2)/T2/T2TR2=1/T2

80C51 C/T2(T2CON.1)/T2C/T2=0;C/T2=1

80C51 CP/RL2(T2CON.0)/CP/RL2=1EXEN2=1T2EXCP/RL2=0/T2EXEN2=1T2EXRCLK=lTCLK=lCP/RL2/T2/T2T2CON

80C51 (2) T2MOD T2MOD80C52/54/58/T20C9H:

2:

D7D6D5D4D3D2D1D0T2OEDCEN

80C51

T2OE(T2MOD.l)/T2T2OE=lT2(P1.0)80C54/80C58DCEN(T2MOD.0)DCEN=l/T2T2MOD =00B

80C51 (3) TH2TL2 /T216,8(TH2)8(TL2)0CDH0CCH/

80C51 (4) RCAP2HRCAP2L /T2168(RCAP2H)8RCAP2L0CBH0CAHRCAP2HRCAP2LTL2TH2TH2TL2RCAP2HRCAP2L()

80C51 2 /T2 /T2C/T2 C/T2=0TH2TL2TL211/12

80C51 C/T2=1T2(Pl.0)TH2TL2l/T0T11/243 /T2 /T2CP/RL2(T2CON.0)RCLK+TCLK/T2(46):

80C51 46/T2

RCLK+TCLKCP /RL2TR2 001011110

80C51 (1) TH2TL2RCAP2HRCAP2LTH2TL2RCAP2HRCAP2L4--11

80C51

411 /T2

80C51 CP/RL2=1: 2TH2TL2TH2TL2RCAP2HRCAP2LTF21

80C51 EXEN2=1T2EX(P1.1)EXF21 /2TF2=1EXF2=1,CPU2BHTF2EXF2CLR TF2CLR EXF2

80C51 (2) RCAP2HRCAP2LTH2TL2RCAP2HRCAP2L8XC524--12

80C51

4--12

80C51 CP/RL2=0: /T2TH2TL2RCAP2HRCAP2LTH2TL2TF21

80C51 EXEN2=1T2EX(P1.1)EXF21 /T2TF2=1EXF2=1,CPU2BHTF2EXF2CLR TF2CLR EXF2

80C51 (3) T2CONRCLK + TCLK=1/T2/T2413T2CON RCLKTCLK /T2 C/T2=01/2

80C51 C/T=1T2(P1.0)11/24 RCAP2HRCAP2LTH2TL2RCAP2HRCAP2L RCLK + TCLK/T1T24--130/T11/T2

80C51

4--13 /T2

80C51 /T2TH2TF2/T2 /T2EXEN21T2EX,EXF21,T2EX

80C51 T2TR2=1/TH2TL21T2T2RCAP2HRCAP2LRCAP2HRCAP2L

80C51 4.2.4 watchdogT3T3

80C51 80C552T3118T34--14 T3EWPCON.4(WLE)PCON.1(PD) EWEW=0EW=1 WLE (PCON.4)WLET3WLE

80C51

4---14 T3

80C51 T3T3T3T38XC552RSTT3T3T3 watchdog T3EQU0FFHT3 PCON EQU 87H PCON

80C51 WATCH_INTV EQU 156 LCALL WATCHDOG WATCHDOG ORL PCON#10H T3 MOV T3# WATCHINTV T3 RET

80C51 4.2.5 /1 / /, ,(TC)1 t=Tc(2L- TC)=12/fosc(2L--TC)

80C51 tTcfoscL T0T10 L=13 213=8 1921 L=16 216=65 5362 L=8 28=256T2L=16 216=65 536

80C51 TC/ =1/t=fosc/12 *1/(2L--TC)tTCTCBTHiTLi(T0i=0T1i=1) /T0T10 TCB=TCH+TCLTCH8TCL5MOV THi# TCH8MOV TLi# TCL5

80C51 1 TCB=TCH+TCL TCH8TCL8MOV THi# TCH8MOVTLi# TCL82 TCB8MOV THi# TCBMOV TLi# TCB/T2T0T11

80C51 2 / /: TMOD/M1M0C/GATE THiTLiTHiTLi TCON

80C51 SETB TRi SETB TCON.4(T0) SETB TCON.6(T1) CLR TRi IEIE.7IE.3IE.1SETB ETiETi SETB EA CLR ETi ETi CLR EA

80C51 3 /1 /T001 msP1.02 msfosc=6 MHz fosc=6 MHz=6106 Hz0L=13L=213=8 192t=1 ms=110-3 s

80C51 TC=2L-fosct/12=8192-610610-3/12 =8 192-500=7 692TCTCB=1 1110 0000 1100 B TCH=0F0HTCL=0CH TMOD

80C51 MOV TMOD#00HMOV TH0#0F0H MOV TL0#0CHSETB TR0 T0SETB ET0 T0SETB EA CPUAJMP $ORG 000BH T0AJMP INQP

80C51 ORG 00H INQP MOV TH0#0F0H MOV TL0#0CH CPL P1.0 P1.0RETI

80C51 2. /T111 msP1.02 msfosc=6 MHz fosc=6 MHz=6106 Hz1L=16 2L=216=65 536

80C51 t=1 ms=110-3 sTC=2L-fosct/12 =65536-610610-312= 65 536-500=65 036 TCTCB=1111 1110 0000 1100 B=0FE0CH TCH=0FEH (8)TCL=0CH(8) TMOD

80C51 ORG 001BHT1 AJMP INQP ORG 100H MOV TMOD#10H MOV TH1#0FEH MOV TL1#0CHSETB TR1 T1

80C51 SETB ET1 T1SETB EA CPU AJMP $ORG 00H INQPMOV TH1#0FEH MOV TL1#0CH CPL P1.0 P1.0 RETI

80C51 3 80C51200 s400 s80C51// /T03 TL0200 sP1.0; TH0400 sP1.1; /T12fosc=9.216MHz

80C51 TL0TCL0tL0=100sTCL0=28921610610010-6/12=25676.8=179.2sTCBL0=0B3H

80C51 TH0TCH0 tH0=200 sTCH0=289.216106200106/12=256-153.6=102.4sTCBH0=66 H TH1()2 400,TC2=0F6H

80C51 ORG 0000H AJMP MAIN

ORG 000BH TL0 AJMP ITL0P ORG 001BH TH0 AJMP ITH0P

80C51 ORG 0100HMAINMOV SP#60H MOV TMOD#23H T03T12 MOV TL0#0B3H TL0 MOV TH0#66H TH0 MOV TL1#0F6H TL1

80C51 MOV TH1#0F6H TH1 SETB TR0 TL0 SETB TR1 TH0 SETB ET0 TL0 SETB ET1 TH0 SETB EA AJMP $

80C51 ORG 200HITL0P MOV TL0#0B3H CPL P1.0 RETIITH0P MOV TH0#66H CPL P1.1 RETI

80C51 4 /T02T0CPU T0CPUTCB=0FFH TMOD

80C51 ORG 000BHT0 RETI ORG 0100H MAIN MOV TMOD#06H T0 2 MOV TL0#0FFH TL0 MOV TH0#0FFH TH0 SETB TR0 SETB ET0 T0

80C51 SETB EA AJMP $ CLR ET0 T0 CLR EA . T0

80C51 5 /4--15GATE4--15/T0INT0/T1T110 3330ms100 ms116

80C51

4---15/

80C51 T0TMOD 9H

1

GATEC/TTM1M01001

80C51 6 MHz100 ms TcTc=12/6106=210-6 s x216-x=10010-3/210-6=50103x=216-50103=15 536 =3CB0H TH0=3CHTL0=0B0H

80C51 /T1212T1T0T0 T1TMOD 5HGATEC/TM1M00101 1 0FFFEHTH1=0FFHTL1=0FEH ORG 0BH T0 AJMP TIME0

80C51 ORG 1BH T1 AJMP TIME1 ORG H MOV R3#0 SETB P3.2 P3.2 P3.5 SETB P3.5 MOV TMOD#59H MOV TH0#3CH MOV TL0#0B0H MOV TH1#0FFH

80C51 MOV TL1#0FEH SETB TR0 SETB TR1 MOV IP#08H T1T0 SETB ET1 T0T1SETB ET0 SETB 20H.1 20H.020H.1

80C51 LOOP SETB 20H.0 SETB ET0 SETB EA JB 20H.0$ JB 20H.1LOOP RET

TIME0 CLR TR0

80C51 MOV TMOD#51HGATE=0 SETB TR1 MOV TH0#3CH MOV TL0#0B0H INC R3 1 CPL 20H.0 RETI

80C51 TIME1CLR 20H.0 CLR 20H.1 CLR ET0 T0T1 CLR ET1 CLR EA CLR TR0; CLR TR1 RETI T0T120H.020H.1R3 R3100 ms256100 ms=25.6 s

80C51 4.3 80C51serial portUART8XC552I2C 80C51UART

80C51 SBUF

80C51 1 UART UART4--16

80C51

4--16UART

80C51 /T1T2/TXCLOCKRXCLOCKTMODTCONT2CONPCONTL1TH1TL2TH2 SBUFSBUF 99H

80C51 TXCLOCKRXCLOCK RITI SCON /TXDP3.1,RXD(P3.0)

80C51 2 SCON SCON8SCON98H98H~9FH

9FH9EH9DH9CH9BH9AH99H98HSM0SM1SM2RENTB8RB8TIRI

80C51 SM0SM14--74--7SM0SM1()

80C51 SM2(SCON.5)230SM2=01SM2=1RI123SM2=19RB80RI09RB81RI1

80C51 REN(SCON.4)/TB8(SCON.3)239/RB8(SCON.2)23910

80C51 TI(SCON.1)08RI(SCON.0)08PCON PCON8,SMOD

80C51

SMODSMOD=1 PCON87H(3) SBUF SBUF8: 99H

D7D6D5D4D3D2D1D0SMODGF1GF0PDIDL

80C51

SBUFMOV SBUFA,SBUFMOVASBUF,

D7D6D5D4D3D2D1D0SD7SD6SD5SD4SD3SD2SD1SD0

80C51 3 SM0SM1SM20:SM0=0SM1=0, 0(1/12)foscRXDP3.0TXDP3.1/8 D0 D1 D2 D3 D4 D5 D6 D704--17

80C51 4--170

80C51 SBUF SBUF19SBUFRXDP3.0;TXD(P3.1)

80C51 0910TI

80C51 2 REN=1RI1111 1110TXDP3.1RXDP3.0

80C51 1111 11100SBUF10RI

80C51 (2) 1 SM0=0SM1=1, 1/T1T2TXDP3.1RXDP3.0 1010811

D0D1D2D3D4D5D6D7

80C51

1418

4181

80C51

80C51 SBUFSBUF19161016SBUF

80C51 TXDP3.1TXDP3.1091010160TI

80C51 14--19

4---191

80C51 REN=1RIRXDP3.010161FFH9116RXDP3.0789

80C51 10RXDP3.11019SBUFRB8RI

80C51 SBUFRB8RI RI=0 SM2=0=1 SBUFRB8RI

80C51 RXDP3.010(3) 23 SM0=1SM1=0, 2SM0=1SM1=1, 3TXDP3.1RXDP3.0

80C51 1110911

D0D1D2D3D4D5D6D7D89

80C51 2321/321/643/T1T224--20

80C51

4--202

80C51 SBUFSBUF19161016SBUF

80C51 TXDP3.1TXDP3.1091011160TI

80C51 REN=1RIRXDP3.110161FFH9116RXDP3.0789

80C51 10RXDP3.01019SBUFRB8RI

80C51 SBUFRB8RI RI=0 SM2=09=1 SBUF9RB8RI

80C51 RXDP3.010(4) SCONSM2(SCON.5)23 SM2=19RB81SBUFRI 1

80C51 SM2=09RB810SBUF42180C511~3

80C51

4--21

80C51 SM21 9TB819TB80 SM219RB81

80C51 SM20 SM21

80C51 4 (baud rate)4---22

80C51

4---22

80C51 0fosc =fosc/12 2foscSMODPCON.7 =fosc/322SMOD/ 2 SMOD=1 =fosc/32SMOD=0 =fosc/64

80C51 13 T1T2SMODPCON.7T1T213 (1) T1C/T=0 =2SMOD/32T1 T1 T10T113 =fosc/12[1/(213-TC+X)]

80C51 TC13X T11T116 =fosc/12[1/(216-TC+X)] T12T18TL1TH1 =fosc/12{1/28-(TH1)}

80C51 2T1 (2) T2 =216T2 = fosc/12{1/216-(RCAP2HRCAP2L)}(RCAP2HRCAP2L)16()

80C51 5 1 1T11 RAM78H77H76H75H

80C51 78H=20H 77H=00H 76H=20H 75H=20HRAM2000H~201FHTRANSANL TMOD#0FH /T1 ORL TMOD#10H 1 MOV TL1#0AAH

80C51 MOV TH1#0AAH SETB EA CLR ES SETB ET1 T1 SETB PT1 T1

80C51 CLR PS SETB TR1 T1 CLR TI MOV SCON#40H 1 MOV SBUF78H

80C51 WAIT1 JNB TIWAIT1 CLR TI MOV SBUF77H WAIT2JNB TIWAIT2 CLR TI MOV SBUF76H WAIT3 JNB TIWAIT3 CLR TI MOV SBUF75H WAIT4 JNB TIWAIT4

80C51 CLR TI SETB ES ORG 001BH T1 AJMP T1INT ORG 0023H AJMP SINT T1INT: CLR TR1 T1

80C51 MOV TL1#0AAH MOV TH1#0AAH SETB TR1 T1 RETI T1

80C51 SINT PUSH DPL PUSH DPH PUSH ACC MOV DPH78H MOV DPL77H MOVX A@DPTR

80C51 CLR TI MOV SBUFA MOV ADPH CJNE A76HEND1 MOV ADPL CJNE A75HEND1 CLR ES CLR ET1 CLR TR1

80C51 ESCOM POP ACC POP DPH POP DPL RETI END1 INC 77H1 MOV A77H JNZ 02H INC 78H SJMP ESCOM

80C51

RXD 1

80C51 RECEIVE ANL TMOD#0FH /T1 ORL TMOD#10H 1 MOV TL1#0AAH MOV TH1#0AAH SETB EA SETB ES SETB ET1 T1 SETB PT1 T1

80C51 CLR PS SETB TR1 T1 MOV SCON#50H 1 CLR B.0 MOV 70H#78H ORG 001BH T1 AJMP RTINT

80C51 ORG 0023H AJMP RSINT RTINT CLR TR1 T1 MOV TL1#0AAH MOV TH1#0AAH SETB TR1 T1 RETI T1

80C51 RSINT PUSH DPL PUSH DPH PUSH ACC MOV AR0 PUSH ACC JB B.0DATA MOV R070H MOV ASBUF 78H~76H MOV @R0A DEC 70H

80C51 CLR RI MOV A#74H CJNE A70HRETURN SETB B.0RETURNPOP ACC MOV R0A POP ACC POP DPH POP DPL RETI

80C51 DATA MOV DPH78H MOV DPL77H MOV ASBUF MOVX @DPTRA RAM CLR RI INC 77H 1 MOV A77H JNZ 02H INC 78H MOV A76H

80C51 CJNE A78HRETURN MOV A75H CJNE A77HRETURN CLR ES CLR ET1 SETB PSW.5 AJMP RETURN

80C51 6 MHzT11T116 = fosc/121/(216-TC+X)X CLR TR1 1 MOV TL1#0AAH 2 MOV TH1#0AAH 2 SERB TR1 1 3 X = 9

80C51 TC =0AAAAH= 43 690221 2/11001~89TB81011/10 212=/n

80C51 SMOD=0 n=64SMOD=1 n=32 233

80C51 (4) 3 31/2 3T12 78H77H000102FE255

80C51 TRANSFER MOV TL1#0F0H MOV TH1#0F0H MOV TMOD#20H 2 SETB EA CLR ES CLR ET1 T1

80C51 SERB TR1 T1 MOV SCON#0E0H 3 SETB TB8 MOV SBUF78H JNB TI$ CLR TI MOV SBUF77H JNB TI,$

80C51 CLR TI MOV IE#90H CLR TB8 MOV A#00H MOV SBUFA WAIT CJNE A#0FEHWAIT CLR ES

80C51 CLR EA HERE AJMP HERE ORG 0023H INC A CLR TI MOV SBUFA RETI 255

80C51 RECEIVE MOV TL1#0F0H MOV TH1#0F0H MOV TMOD#20H 2 SETB ES CLR ET1 T1

80C51 SETB EA SETB TR1 T1 MOV SCON#0F0H 3 MOV R0#0FEH RWAIT AJMP RWAIT ORG 0023H

80C51 MOV CRB8 JNC PD2 INC R0 NOP MOV AR0 JZ PD MOV DPHSBUF AJMP PD1

80C51 PD MOV DPLSBUF CLR SM2 PD1 CLR RI RETI PD2 MOV ASBUF MOVX @DPTRA INC DPTR CLR RI CJNE A#0FEHRETURN

80C51 CLR ES RETURN RETI 212

80C51 4.4 4.4.1 CPU4--234--23

80C51

(2)

80C51 (3) CPUCPUCPU 80C514--2480C51

80C51

4--2480C51

80C51 4.4.2 80C5180C52/T280C51 INT0P3.20IT0TCON.0=0IT0TCON.0=1 INT1P3.31IT1TCON.2=0IT1TCON.2=1

80C51 TF0P3.4/T0 TF1P3.5/T1RX,TX2. INT0INT1T0T1TCON/SCON TCON88H

80C51

SCON98H

8FH8EH8DH8CH8BH8AH89H88HTF1TF0IE1IT1IE0IT0

9FH9EH9DH9CH9BH9AH99H98HTIRI

80C51 TF1TCON.7T10TF0TCON.5T00 IE1TCON.3IE1=1INT1CPUIE0TCON.1IE0=1INT0CPU

80C51 TISCON.10RISCON.00TCONIT1TCON.2IT0TCON.03. IEA8H

80C51

IE01IE0 EX0IE.00 ET0IE.1/T0 EX1IE.21

AFHAEHADHACHABHAAHA9HA8HEAESET1EX1ET0EX 0

80C51 ET1IE.3/T1 ESIE.4 EAIE.7CPUEA=1EA=04. 80C51IPIP0B8H

BFHBEHBDHBCHBBHBAHB9HB8HPSPT1PX1PT0PX0

80C51 IP01IP0 CLR EA CPUCPUINT0T0INT1T1

80C51 5 INT0INT1TCONIT1TCON.2IT0TCON.0IT1IT0=0IT1IT0=1INT0INT1IE0IE1CPU

80C51 CPUINT0INT1INT0INT1INT0INT1CPUINT0INT1CPU

80C51 6 CPURETI /T0T1CPUTF0TF1IE0IE1

80C51 /80C52/T2CPURITITF2EXF2 CPUINT0INT1CPU

80C51 4.4.3 4--25

80C51 4--25 S5P2CPUS61 LCALLPC2

80C51 PC RETI RETIPC2

80C51 LCALL RETIIEIP/

80C51 (2) 4--84--8 0INT0 0003H/0T0 000BH1INT1 0013H/1T1 001BHRITI 0023H2(T2) 002BH