MCS??51??????????????
MCS-51??????????????(1) P3 TCON
P3?????湦??
????????B0H??λ??B7H??B0H??
???? | P3.0 | P3.1 | P3.2 | P3.3 | P3.4 | P3.5 | P3.6 | P3.7 |
???湦?? | | TXD | /INT0 | /INT1 | T0 | T1 | /WR | /RD |
TCON???????????????
????????88H??λ??8FH??88H??
λ??? | 8F | 8E | 8D | 8C | 8B | 8A | 89 | 88 |
λ???? | TF1 | TR1 | TF0 | TR0 | IE1 | IT1 | IE0 | IT0 |
TF0(TF1)——??????????λ??????????????????????λ??1??
TR0(TR1)——????????п???λ
??TR0(TR1)=0 ???????/??????????
??TR0(TR1)=1 ?????????/??????????
IE0(IE1)——???ж???????λ
??CPU??????P3.2(P3.3)??????Ч?ж??????????λ???????1?????ж????????????ж???????????????????0??
IT0(IT1)——???ж??????????????λ
??IT0(IT1)=1 ???巽?(?????????Ч)
??IT0(IT1)=0 ??????(??????Ч)??λ????????1????0??
TF0(TF1)——??????????λ
????????????????????????λ???????1????????ж???????????????????0?????????????λ?????????????????????ж?????????ж???????λ?????;???ò???????????????λ????á?
MCS-51??????????????(2) TMOD T2MOD
TMOD?????????????????
????????89H??????λ????
λ?? | B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 |
λ???? | GATE | C/T | M1 | M0 | GATE | C/T | M1 | M0 |
GATE——???λ
??=0?????????TR0(??TR1)?????????????????????
??=1?????TR0*/INT0(??TR1*/INT1)?????????????????????
GATE=0 ??TR0(TR1)?????????
GATE=1 ??INT0(INT1)?????????
C/T=0 ???/??????????????λ
M1M0——??????????λ
T2MOD?????????????????
????????0C9H??????λ??
?? | ?? | ?? | ?? | ?? | ?? | T2OE | DCEN |
T2OE???????2???????λ????=1???P1.0/T2??????????????????
DCEN????=1???T2???ó??????????????
MCS-51??????????????(3) T2CON
T2CON???????????????
????????0C8H??λ??0C8H??0CFH??
λ??? | CF | CE | CD | CC | CB | CA | C9 | C8 |
λ???? | TF2 | EXF2 | RCLK | TCLK | EXEN2 | TR2 | C/T2 | CP/RL2 |
TF2??T2??????
??T2????TF2=1??TD2????????????
??RCLK=1??TCLK=1???TF2??????λ
EXF2??T2?????
??EXEN2=1???T2EX/P1.1????????????????T2????/????????????EXF2=1????T2?ж????????EXF2=1???????ж??EXF2????????????????T2??????????????????(DCEN=1)EXF2????λ?????????ж??
RCLK?????????????
??RCLK=1???T2?????????????????п??????????????????п???1??3??RCLK=0???T1????????????????п??????????
TCLK?????????????
EXEN2??T2?????(?????/??????????)????
??EXEN2=1??????T2???????????????(??RCLK+TCLK=0)??????T2EX/P1.1???????佫????T2????/???????;
??EXEN2=0?????T2EX?????????佫????????
TR2??T2??????/??????
C/T2?????????
CP/RL2?????/??????
??CP/RL2=1??EXEN2=1???T2EX/P1.1?????????佫?????????
??CP/RL2=0??EXEN2=1???T2EX/P1.1?????????佫???????????
??CP/RL2=0??EXEN2=0???T2???????????T2????????????
??RCLK+TCLK=1???CP/RL2????λ?????????T2??????????????????????????????T2???????????????????????????
MCS-51??????????????(4) SCON
SCON?????п????????
????????98H??λ??9FH??98H??
λ??? | 9F | 9E | 9D | 9C | 9B | 9A | 99 | 98 |
λ???? | SM0 | SM1 | SM2 | REN | TB8 | RB8 | TI | RI |
SM0??SM1?????п??????????λ
SM2???????????λ
REN??????/??????п????????λ
TB8??????2????3?У??????????9λ?????????????????????1?????????????????У??λ??????1??????λ??
RB8??????2????3?У??????????9λ????(?????TB8λ);????1?У?RB8?????????λ??????0?в??á?
TI——???п?????ж???????λ
??????????????????????????1;??????ж????????????????0??
RI——???п?????ж???????λ
??????????????????????????1;??????ж????????????????0??
MCS-51??????????????(5) IE?ж????? IP?ж?????
IE???ж?????????????
????????A8H??λ??AFH??A8H??
λ??? | AF | AE | AD | AC | AB | AA | A9 | A8 |
λ???? | EA | / | ET2 | ES | ET1 | EX1 | ET0 | EX0 |
EA???ж??????????λ
??EA=0????ж???????
??EA=1????ж??????????ж??????????????ж?????ж?????????λ???????á?
EX0( EX1)?????ж?????????λ
??EX0( EX1)=0 ??????ж?
??EX0( EX1)=1 ???????ж?
ET0(EX1)?????/?????ж?????????λ
??ET0(ET1)=0 ??????(?????)?ж?
??ET0(ET1)=1 ???????(?????)?ж?
ET2???????2?ж?????????λ????AT89S52??AT89C52??
ES???????ж?????????λ
??ES=0 ????????ж?
??ES=1 ?????????ж?
IP???ж??????????????
????????B8H??λ??BFH??B8H??
λ??? | BF | BE | BD | BC | BB | BA | B9 | B8 |
λ???? | / | / | PT2 | PS | PT1 | PX1 | PT0 | PX0 |
PX0——???ж?0??????趨λ
PT0——????ж?0??????趨λ
PX1——???ж?1??????趨λ
PT1——????ж?1??????趨λ
PS——?????ж???????趨λ
PT2——?????2??????趨λ
MCS-51??????????????(6) PSW PCON
PSW??????????
????????D0H??λ??D7H??D0H??
λ??? | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
λ???? | CY | AC | F0 | RS1 | RS0 | OV | - | P |
CY——??λ???
AC——???λ???
F0——????趨???
RS1 ??RS0——4??????????????????λ??
VO——??????
P——???У????
PCON??????????????????????????
?????=87H??????λ??
SMOD | - | - | POF | GF1 | GF0 | PD | IDL |
SMOD——?????????λ
GF1??GF0——????????
PD——???緽?????λ??PD=1??????????
IDL——???з??????λ??IDL=1???????з??
??AT89S51??PCON.4?????????λPOF????????1
51????????
???????????PCON=0x01; ?????AUXR=0xFF;???????????????WDT????????
PCON??????????????????????????
?????=87H??????λ??
SMOD | - | - | POF | GF1 | GF0 | PD | IDL |
SMOD——?????????λ
GF1??GF0——????????
PD——???緽?????λ??PD=1??????????
IDL——???з??????λ??IDL=1???????з??
??AT89S51??PCON.4?????????λPOF????????1??
??????????ο?????????????MCU??
????admin ?????????2018-05-19
