Special Function Registers of 8051

Name of FSR

Name of FSR

Byte Address

Bit Address

Function of FSR

A

Accumulator

0E0H

0E7H...0E0H

USED TO HOLD DATA AND STATUS DURING PROGRAMMING

B

Arithmetic

0F0H

0F7H…0F0H

PSW

Program status word

0D0H

SP

Stack pointer

81H

81H

USED IN INSTRUCTIONS TO POINT POINTER

DPL

Address external memory

82H

82H

DPH

Address external memory

83H

83H

P0

I/O Port

80H

87H…80H

USED BY RESPECTIVE I/O PORTS

P1

I/O Port

90H

97H…90H

P2

I/O Port

A0H

0A7H…0A0H

P3

I/O Port

B0H

0B7H…0B0H

SCON

Serial Port control

98H

9FH…98H

USED BY SERIAL PORT

SBUF

Serial Port Data Buffer

99H

99H

USED FOR TIMER CONTROL

TCON

Timer/Counter control

88H

8FH…88H

TMOD

Timer/Counter ode control

89H

89H

TL0

Timer 0 low byte

8AH

8AH

TL1

Timer 1 low byte

8BH

8BH

TH0

Timer 0 high byte

8CH

8CH

TH1

Timer 1 high byte

8DH

8DH

IE

Interrupt enable

0A8H

0AFH…0A8H

USED FOR INTERRUPT CONTROL

IP

Interrupt priority

0B8H

0BFH…0B0H

PCON

Power control

87H

87H

USED FOR POWER CONTROL