
5
AT89C51ID2
4289C–8051–11/05
Table 2. C51 Core SFRs
Mnemonic
Add
Name
765432
10
ACC
E0h
Accumulator
B
F0h
B Register
PSW
D0h
Program Status Word
CY
AC
F0
RS1
RS0
OV
F1
P
SP
81h
Stack Pointer
DPL
82h
Data Pointer Low byte
DPH
83h
Data Pointer High byte
Table 3. System Management SFRs
Mnemonic
Add
Name
765432
10
PCON
87h
Power Control
SMOD1
SMOD0
-
POF
GF1
GF0
PD
IDL
AUXR
8Eh
Auxiliary Register 0
-
M0
XRS1
XRS0
EXTRA
M
AO
AUXR1
A2h
Auxiliary Register 1
-
ENBOO
T
-GF3
0
-
DPS
CKRL
97h
Clock Reload Register
----
CKSEL
85h
Clock Selection Register
----
---
CKS
OSCON
86h
Oscillator Control Register
----
-
SCLKT0
OscBEn
OscAEn
CKCKON0
8Fh
Clock Control Register 0
TWIX2
WDTX2
PCAX2
SIX2
T2X2
T1X2
T0X2
X2
CKCKON1
AFh
Clock Control Register 1
----
---
SPIX2
Table 4. Interrupt SFRs
Mnemonic
Add
Name
765432
10
IEN0
A8h
Interrupt Enable Control 0
EA
EC
ET2
ES
ET1
EX1
ET0
EX0
IEN1
B1h
Interrupt Enable Control 1
----
-
ESPI
ETWI
EKBD
IPH0
B7h
Interrupt Priority Control High 0
-
PPCH
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
IPL0
B8h
Interrupt Priority Control Low 0
-
PPCL
PT2L
PSL
PT1L
PX1L
PT0L
PX0L
IPH1
B3h
Interrupt Priority Control High 1
----
-
SPIH
IE2CH
KBDH
IPL1
B2h
Interrupt Priority Control Low 1
----
-
SPIL
IE2CL
KBDL