80C451 Datasheet, PDF (8/22 Pages) NXP Semiconductors – 80C51 8-bit microcontroller family 4K/128 OTP/ROM/ROMless, expanded I/O

Philips Semiconductors
80C51 8-bit microcontroller family
4K/128 OTP/ROM/ROMless, expanded I/O
Product specification
80C451/83C451/87C451
Table 2. 8XC451 Special Function Registers
SYMBOL
DESCRIPTION
DIRECT
ADDRESS MSB
BIT NAMES AND ADDRESSES
ACC*
Accumulator
E0H
E7
E6
E5
E4
E3
E2
B*
B register
F0H
F7
F6
F5
F4
F3
F2
EF
EE
ED
EC
EB
EA
CSR*# Port 6 command/status
E8H
MB1 MB0 MA1 MA0 OBFC IDSM
DPTR
Data pointer (2 bytes)
DPH
Data pointer high
83H
DPL
Data pointer low
82H
BF
BE
BD
BC
BB
BA
IP*
Interrupt priority
B8H
–
–
–
PS PT1 PX1
E1
F1
E9
OBF
B9
PT0
LSB
E0
F0
E8
IBF
RESET
VALUE
00H
00H
FCH
00H
00H
B8
PX0 xxx00000B
IE*
P0*
P1*
P2*
P3*
P4*#
P5*#
P6*#
Interrupt enable
Port 0
Port 1
Port 2
Port 3
Port 4
Port 5
Port 6
A8H
80H
90H
A0H
B0H
C0H
C8H
D8H
AF
AE
AD
AC
AB
AA
A9
A8
EA
–
–
ES ET1 EX1 ET0 EX0 0xx00000B
87
B6
85
84
83
82
81
80 FFH
97
96
95
94
93
92
91
90 FFH
A7
A6
A5
A4
A3
A2
A1
A0 FFH
B7
B6
B5
B4
B3
B2
B1
B0 FFH
C7
C6
C5
C4
C3
C2
C1
C0 FFH
CF
CE
CD
CC
CB
CA
C9
C8 FFH
DF
DE
DD
DC
DB
DA
D9
D8 FFH
PCON Power control
87H
SMOD –
–
–
GF1 GF0 PD IDL 0xxx0000B
PSW*
SBUF
Program status word
Serial data buffer
SCON*
SP
Serial port control
Stack pointer
TCON* Timer/counter control
D0H
99H
98H
81H
88H
D7
D6
D5
D4
D3
D2
D1
CY
AC
F0 RS1 RS0 OV
–
9F
9E
9D
9C
9B
9A
99
SM0 SM1 SM2 REN TB8 RB8
TI
8F
8E
8D
8C
8B
8A
89
TF1 TR1 TF0 TR0 IE1
IT1
IE0
D0
P 00H
xxxxxxxxB
98
RI 00H
07H
88
IT0 00H
TMOD Timer/counter mode
89H
GATE C/T M1
M0 GATE C/T M1
M0 00H
TH0
Timer 0 high byte
8CH
00H
TH1
Timer 1 high byte
8DH
00H
TL0
Timer 0 low byte
8AH
00H
TL1
Timer 1 low byte
8BH
00H
* SFRs are bit addressable.
# SFRs are modified from or added to the 80C51 SFRs.
1998 May 01
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