Philips Semiconductors
Product specification
CMOS single-chip 8-bit microcontrollers
80C31/80C51/87C51
Table 1.
80C52/80C54/80C58 Special Function Registers
DIRECT
DESCRIPTION
BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION
RESET
VALUE
SYMBOL
ADDRESS MSB
LSB
ACC*
AUXR#
AUXR1#
B*
Accumulator
Auxiliary
E0H
8EH
A2H
F0H
E7
–
E6
–
E5
–
E4
–
E3
–
E2
–
E1
–
E0
00H
AO
DPS
F0
xxxxxxx0B
xxxx00x0B
00H
Auxiliary 1 (Note 2)
B register
–
–
–
–
WUPD
F3
0
–
F7
F6
F5
F4
F2
F1
DPTR:
DPH
DPL
Data Pointer (2 bytes)
Data Pointer High
Data Pointer Low
83H
82H
00H
00H
AF
EA
BF
–
AE
EC
BE
–
AD
ET2
BD
AC
ES
BC
PS
B4
AB
ET1
BB
AA
EX1
BA
A9
ET0
B9
A8
EX0
B8
IE*
Interrupt Enable
Interrupt Priority
Interrupt Priority High
Port 0
A8H
B8H
B7H
80H
90H
A0H
00H
IP*
PT2
B5
PT1
B3
PX1
B2
PT0
B1
PX0
B0
x0000000B
x0000000B
FFH
B7
–
B6
–
IPH#
P0*
P1*
P2*
P3*
PT2H
85
PSH
84
PT1H
83
PX1H PT0H
PX0H
80
87
86
82
AD2
92
81
AD1
91
AD7
97
AD6
96
AD5
95
AD4
94
AD3
93
AD0
90
Port 1
–
–
–
–
–
–
T2EX
A1
T2
FFH
A7
AD15
B7
RD
A6
AD14
B6
WR
A5
A4
A3
A2
A0
Port 2
AD13
B5
AD12
B4
AD11
B3
AD10
B2
AD9
B1
AD8
B0
FFH
Port 3
B0H
87H
T1
T0
INT1
INT0
TxD
RxD
FFH
1
PCON#
Power Control
SMOD1
D7
SMOD0
D6
–
–
GF1
D3
GF0
D2
PD
D1
–
IDL
D0
P
00xx0000B
D5
F0
D4
PSW*
Program Status Word
D0H
CY
AC
RS1
RS0
OV
00H
SADDR#
SADEN#
Slave Address
Slave Address Mask
A9H
B9H
00H
00H
SBUF
Serial Data Buffer
99H
xxxxxxxxB
9F
9E
9D
9C
9B
9A
99
TI
98
RI
SM0/FE
SCON*
SP
Serial Control
Stack Pointer
98H
81H
SM1
SM2
REN
TB8
RB8
00H
07H
8F
TF1
CF
–
8E
TR1
CE
–
8D
TF0
CD
–
8C
TR0
CC
–
8B
IE1
CB
–
8A
IT1
CA
–
89
IE0
88
IT0
TCON*
Timer Control
88H
00H
C9
C8
T2MOD#
TH0
TH1
TL0
TL1
Timer 2 Mode Control
Timer High 0
Timer High 1
Timer Low 0
Timer Low 1
C9H
8CH
8DH
8AH
8BH
T2OE
DCEN
xxxxxx00B
00H
00H
00H
00H
TMOD
Timer Mode
89H
GATE
C/T
M1
M0
GATE
C/T
M1
M0
00H
*
SFRs are bit addressable.
#
–
SFRs are modified from or added to the 80C51 SFRs.
Reserved bits.
1. Reset value depends on reset source.
2. Available only on SC80C51.
8
1996 Aug 16
NXP [ NXP ]
