
Preliminary W79E648
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Special Function Registers
The W79E648 uses Special Function Registers (SFRs) to control and monitor peripherals and their
Modes.
The SFRs reside in the register locations 80-FFh and are accessed by direct addressing only. Some
of the SFRs are bit addressable. This is very useful in cases where one wishes to modify a particular
bit without changing the others. The SFRs that are bit addressable are those whose addresses end in
0 or 8. The W79E648 contains all the SFRs present in the standard 8052. However, some additional
SFRs have been added. In some cases unused bits in the original 8052 have been given new
functions. The list of SFRs is as follows. The table is condensed with eight locations per row. Empty
locations indicate that there are no registers at these addresses. When a bit or register is not
implemented, it will read high.
Table 1. Special Function Register Location Table
F8
EIP
F0
B
E8
EIE
E0
ACC
D8
WDCON
PWMP
PWM0
PWM1
PWMCON1 PWM2
PWM3
D0
PSW
C8
T2CON
T2MOD
RCAP2L
RCAP2H
TL2
TH2
PWMCON2 PWM4
C0
PWM5
PMR
STATUS
TA
B8
IP
SADEN
B0
P3
P5
P6
P7
A8
IE
SADDR
ROMCON
SFRAL
SFRAH
SFDFD
SFRCN
A0
P2
XRAMAH
P4CSIN
P4
98
SCON0
SBUF
P42AL
P42AH
P43AL
P43AH
CHPCON
90
P1
P4CONA
P4CONB
P40AL
P40AH
P41AL
P41AH
88
TCON
TMOD
TL0
TL1
TH0
TH1
CKCON
80
P0
SP
DPL
DPH
PCON
Note: The SFRs in the column with dark borders are bit-addressable.