SPECIAL FUNCTION REGISTERS (SFRs) of 8051

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SPECIAL FUNCTION REGISTERS (SFRs) of 8051
SPECIAL FUNCTION REGISTERS (SFRs) of 8051
In 8051 microcontroller there certain registers which uses the RAM addresses from 80h to FFh and they are meant for certain specific operations .These registers are called Special function  registers (SFRs).Some of these registers are bit addressable also. The list of SFRs and their functional names are given below. In these SFRs some of them are related to  I/O ports (P0,P1,P2 and P3) and some of them are meant for control operations (TCON,SCON, PCON..) and remaining are  the auxillary SFRs, in the sense that they don't directly configure the 8051.

The following table shows the layout of each record in 8051 and 8052 microcontroller.


F8HFFH
F0HB * F7H
E8HEFH
E0hACC * E7H
D8HDFH
D0HPSW * D7H
C8HT2CON * # RCAP2L # RCAP2H # TL2 # TH2 # CFH
C0hC7H
B8HIP * BFH
B0hP3 * B7H
A8hIE * AFH
A0HP2 * A7H
98HSCON * SBUF9FH
90HP1 * 97H
88hTCON * TMODTL0TL1TH0TH18FH
80HP0 * SPDPLDPHPCON87H
The following table shows the description and the symbols of each bit or pin of the internal registers (SFR) of the 8051/8052 microcontroller family.
RegisterDescriptionAddressCommand bit or alternate function portReset value
MSBLSB
ACC *Accumulator
(Accumulator)		E0hE7E6E5E4E3E2E1E000H
B *Register B
(Register B)		F0HF7F6F5F4F3F2F1F000H
DPTR:Data Pointer
(Data Pointer) (2 bytes)
DPHHigh byte of DPTR
(Data pointer high)		83H00H
DPLLow byte of DPTR
(Data pointer low)		82H00H
AFAEADACABAAA9A8
IE *Enable interrupts
(Interrupt enable)		A8hEA-ET2ESET1EX1ET0EX00x000000B
BFBEBDBCBBBAB9B8
IP *Priority interrupts
(Interrupt priority)		B8H--PT2PSPT1PX1PT0PX00x000000B
8786858483828180
P0 *Port 0 (Port 0)80HAD7AD6AD5AD4AD3AD2AD1AD0FFH
9796959493929190
P1 *Port 1 (Port 1)90H------T2EXT2FFH
A7A6A5A4A3A2A1A0
P2 *Port 2 (Port 2)A0HA15A14A13A12A11A10A9A8FFH
B7B6B5B4B3B2B1B0
P3 *Port 3 (Port 3)B0hRDWRT1T0INT1INT0TxDRxDFFH
PCON1Consumption control
(Power control)		87HSMOD---GF1GF0PDIDL0xxxxxxxB
D7D6D5D4D3D2D1D0
PSW *Program status word
(Program status word)		D0HCYACF0RS1RS0OV-P00H
RegisterDescriptionAddressBit command or alternate function portReset value
MSBLSB
RCAP2H #Capture high byte
(Capture high)		CBH00H
RCAPL #Capture Low byte
(Capture low)		CAH00H
SBUFSerial Data Buffer
(Serial data buffer)		99hxxxxxxxxB
9F9E9D9C9B9A9998
SCON *Serial Port Control
(Serial controller)		98HSM0SM1SM2RENTB8Rb8ITRI00H
SPStack pointer
(Stack Pointer)		81F07H
8F8E8D8C8B8A8988
TCON *Control Timers
(Timer Control)		88hTF1TR1TF0TR0IE1IT1IE0IT000H
CFCECDCCCBCAC9C8
T2CON * #Timer 2 Control
(Timer 2 contro l)		C8HTF2EXF2RCLKTCLKEXEN2TR2C/T2CP/RL200H
TH0Timer 0 upper
(Timer high 0)		8CH00H
TH1Timer 1 upper
(Timer high 1)		8DH00H
TH2 #Timer 2 top
(Timer high 2)		CDH00H
TL0Timer 0 lower
(Timer Low 0)		8AH00H
TL1Timer 1 lower
(Timer Low 1)		8BH00H
TL2 #Timer 2 lower
(Timer Low 2)		CCH00H
TMODTimers Mode
(Timer mode)		89hGATEC / TM1M0GATEC / TM1M000H
* Register with bit-level addressing.
# Records added in the 8052 microcontroller family.

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