51???????????????????SFR??
??51?????????????CPU??????????????????????I/O????????P0??P1??P2??P3????ROM??????????????RAM??????????м??????????ж??/????????????I/O????ж????????????????????·?????????????Щ??????洢???????????????Щ???????????????????????(SFR)??????????????????51?????????21???????????????б??????
???? | ??? | ??????? |
B | F0H | B????? |
ACC ?? | E0H | ????? |
PSW ?? | D0H | ???????? |
IP ?? | B8H | ?ж?????????????? |
P3 ?? | B0H | P3???????? |
IE ?? | A8H | ?ж????????????? |
P2 ?? | A0H | P2???????? |
SBUF | 99H | ???п??????? |
SCON | 98H | ???п???????? |
P1 ?? | 90H | P1???????? |
TH1 ?? | 8DH | ?????/??????1????8λ?? |
TH0 | 8CH | ?????/??????1????8λ?? |
TL1 | 8BH | ?????/??????0????8λ?? |
TL0 ?? | 8AH | ?????/??????0????8λ?? |
TMOD | 89H | ?????/????????????????? |
TCON | 88H | ?????/?????????????? |
DPH ?? | 83H | ???????????8λ?? |
DPL | 82H | ???????????8λ?? |
SP | 81H | ?????? |
P0 | 80H | P0???????? |
PCON | 87H | ??????????? |
???????????
1??ACC---??????????????A?????
????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????ACC?е????ɡ??????????????????????????????????????????????????????е???????????????????????????????Z????A=0??Z=1;??A≠0??z=0???????????????????????ж???????
2??B--??????????
????????????????????????????????????????????á?
3??PSW-----???????????????????????????????????CPU???????????????????????????CPU?????????????????????????????λ???????±???
D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 |
CY ?? | AC | F0 | RS1 | RS0 | OV | ?? | P |
????????????????λ?????
CY????λ?????8051?е????????????8λ???????????????????8λ?????????????0-255????????????????????????????255?????????λ??????????????????????????λ??????????????????????????н?????λ??CY=1;???????λ??CY=0
????78H+97H(01111000+10010111)
AC????????????λ(????????????????????λ)??
????57H+3AH(01010111+00111010)
F0????????λ???????(??????)??????????????????á?
RS1??RS0????????????????λ???????????????
0V????????λ?????????????????????????????OV=1;???????OV=0?????????????????????????
P?????У??λ???????????ALU???????ж???????λ“1”????????????????????????P=1???????0????????????????1??P=1;?????????????1??P=0??
?????????????78H(01111000)?????1???????????????P=0??
4??DPTR(DPH??DPL)--------???????????????????????????洢???е???????????????????????????ü???????????????????????????á????DPL(??8λ)??DPH(??8λ)??????????????????16λ??????????ü???????????????????????RAM?????洢????64K????Χ????????????
5??P0??P1??P2??P3------????????????????????????????/???????????????????????????????????
6??IE-----?ж?????????
??λ?????????A8H
B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 |
EA ?? | - | ET2 | ES | ET1 | EX1 | ET0 | EX0 |
EA (IE.7)??EA=0????????ж???(?????????ж?)
EA=1??????ж???????????????λ????
- (IE.6)??????
ET2(IE.5)?????2????ж????(8052??)
ES (IE.4)?????п??ж????(ES=1??????ES=0???)
ET1(IE.3)?????1?ж????
EX1(IE.2)?????ж?INT1?ж????
ET0(IE.1)???????0?ж????
EX0(IE.0)?????ж?INT0???ж?????
7??IP-----?ж??????????????
??λ???????λB8H
B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 |
-?? | - | PT2 | PS | PT1 | PX1 | PT0 | PX0 |
- (IP.7)??????
- (IP.6)??????
PT2(IP.5)?????2?ж?????(8052??)
PS (IP.4)?????п??ж?????
PT1(IP.3)?????1?ж?????
PX1(IP.2)?????ж?INT1?ж?????
PT0(IP.1)???????0?ж?????
PX0(IP.0)?????ж?INT0???ж?????
8??TMOD-----?????????????
????λ???????89H
B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 |
GATE ?? | C/T | M1 | M0 | GATE | C/T | M1 | M |
GATE ????????????????λ????GATE=1???INT0??INT1?????????????TCON?е?TR0??TR1????λ?1??????/??????0??1????????????GATE=0????????TR0??TR1????λ???1?????/??????0??1??????????
C/T ??????????????????????λ??C/T=1??????????????????T0??T1??????????塣C/T=0???????????????????????????????塣
M1 ???????λ??λ
M0 ???????λ??λ
M1 | M0 | ?????? |
0 | 0 | 13λ????/????? |
0 | 1 | 16λ????/????? |
1 | 0 | 8λ??????????/????? |
1 | 1 | ?????1?????????????0?????????????8λ?????TH0??TL0 |
9??TCON-----?????????????
??λ??????? | B6 | B5 | B4 | B3 | B2 | B1 | B0 |
TF1?? | TR1 | TF0 | TR0 | IE1 | IT1 | IE0 | IT0 |
803l?????????21????????????????(SFR)????????ü???????????????????????·?????з?????????·?????????????????й?????????????????????У????а???к????I/O?????????????????????Щ????????д???????????I/O?????????????????
21????????????????????????128??????SFR?洢????У????????80H-FFH???????SFR????У???????128??λ????????????80H-FFH???????83????Чλ????????11???????????????Щλ??λ????????
??λ????SFR??????
|
???? | ??? | ??????? |
B | F0H | B????? |
ACC ?? | E0H | ????? |
PSW ?? | D0H | ???????? |
IP ?? | B8H | ?ж?????????????? |
P3 ?? | B0H | P3???????? |
IE ?? | A8H | ?ж????????????? |
P2 ?? | A0H | P2???????? |
SBUF | 99H | ???п??????? |
SCON | 98H | ???п???????? |
P1 ?? | 90H | P1???????? |
TH1 ?? | 8DH | ?????/??????1????8λ?? |
TH0 | 8CH | ?????/??????1????8λ?? |
TL1 | 8BH | ?????/??????0????8λ?? |
TL0 ?? | 8AH | ?????/??????0????8λ?? |
TMOD | 89H | ?????/????????????????? |
TCON | 88H | ?????/?????????????? |
DPH ?? | 83H | ???????????8λ?? |
DPL | 82H | ???????????8λ?? |
SP | 81H | ?????? |
P0 | 80H | P0???????? |
PCON | 87H | ??????????? |
???棬??????????????????SFR??
??????????51???????????
????admin ?????????2018-05-19
