Principais registradores do 8051.
Nome Descrição Endereço
-------- ------------- -------------
ACC Acummulator E0
B B register F0
DPTR DataPointer
DPH DataPointer high 83
DPL DataPointer low 82
IE Interrupt Enable A8
IP Interrupt Priority B8
P0 Port 0 80
P1 Port 1 90
P2 Port 2 A0
P3 Port 3 B0
PCON Power control 87
PSW Program status word D0
SBUF Serial Databuffer 99
SCON Serial controller 98
SP Stack Pointer 81
TCON Timer Control 88
TH0 Timer high 0 8C
TH1 Timer high 1 8D
TL0 Timer low 0 8A
TL1 Timer low 1 8B
TMOD Timer mode 89
IP
Bit Descrição Simbolo
---- ---------------- --------------
B7 reserved
B6 reserved
B5 reserved
B4 priority of serial port interrupt PS
B3 priority of timer 1 interrupt PT1
B2 priority of external interrupt 1 PX1
B1 priority of timer 0 interrupt PT0
B0 priority of external interrupt 0 PX0
IE
Bit Descrição Simbolo
---- ---------------- --------------
B7 enable all interrupts EA
B6 reserved
B5 reserved
B4 Enable serial port interrupt ES
B3 Enable timer 1 interrupt ET1
B2 Enable external interrupt 1 EX1
B1 Enable timer 0 interrupt ET0
B0 Enable external interrupt 0 EX0
PSW
Bit Descrição Simbolo
---- ---------------- --------------
B7 Carry flag CY
B6 Auxiliary carry flag AC
B5 General purpose status flag F0
B4 Register bank select bit 1 RS1
B3 Register bank select bit 0 RS0
B2 OverFlow flag OV
B1 User definable
B0 Parity of accumulator P
SCON
Bit Descrição Simbolo
---- ---------------- --------------
B7 serial port mode SM0
------------------------------------------------------------------------------------------
B6 serial port mode SM1
------------------------------------------------------------------------------------------
B5 Enable multiprocessorfeature in modes 2 & 3 SM2
RI will not be activated if RB8=0 & SM2=1 in mode 1 RI will not be activated if stop bit was invalid & SM2=1 SM2 should be 0 in mode 0
------------------------------------------------------------------------------------------
B4 enable reception REN
------------------------------------------------------------------------------------------
B3 in modes 2&3 9-th bit tx TB8
------------------------------------------------------------------------------------------
B2 in modes 2&3 9-th bit rx RB8
mode1 ; if SM2=0 RB8=stop bit value
mode0 ; not used
------------------------------------------------------------------------------------------
B1 tx interrupt flag TI
mode0 : set by 8-th bit time
other modes : set by beginning of stop bit
------------------------------------------------------------------------------------------
B0 rx interrupt flag RI
------- ---------------- ----------------
00 shift register f_osc/1201
8-bit UART variable10
9-bit UART f_osc/64 of f_osc/3211
9-bit UART variable
------------------------------------------------------------------------------------------
TCON
Bit Descrição Simbolo
---- ---------------- --------------
B7 timer 1 overflow flag TF1
B6 timer 1 on/off control TR1
B5 timer 0 overflow flag TF0
B4 timer 0 on/off control TR0
B3 interrupt 1 edge flag IE1
B2 interrupt 1 triggercontrol bit IT1
B1 interrupt 0 edge flag IE0
B0 interrupt 0 triggercontrol bit IT0
TMOD
Bit Descrição Simbolo
---- ---------------- --------------
B7 0 = t/c 1 enabled via TR1 GATE
1 = t/c enabled via INT1 + TR1
B6 timer = 0, counter = 1 T/C
B5 operating modes t/c 1 M1
B4 operating modes t/c 1 M0
B3 idem for t/c 0B2 idem for t/c 0
B1 idem for t/c 0B0 idem for t/c 0
Modes
---------
00 TLx serves as 5-bit prescaler
01 16-bit t/c THx & TLx are cascaded
10 8-bit reloader, valTHx is loaded in TLx when TLx overflows
11 TL0 is an 8-bit t/c controlled by Timer 0 controlbits TH0 is an 8-bit t/c controlled by Timer 1 controlbits t/c 1 stopped
