AT89S53
XTAL1
Special Function Registers
A map of the on-chip memory area called the Special Func-
tion Register (SFR) space is shown in Table 1.
Input to the inverting oscillator amplifier and input to the
internal clock operating circuit.
XTAL2
Note that not all of the addresses are occupied, and unoc-
cupied addresses may not be implemented on the chip.
Read accesses to these addresses will in general return
random data, and write accesses will have an indeterminate
effect.
Output from the inverting oscillator amplifier.
Table 1. AT89S53 SFR Map and Reset Values
0F8H
0FFH
0F7H
0EFH
0E7H
0DFH
B
0F0H
00000000
0E8H
ACC
0E0H
00000000
0D8H
PSW
0D0H
SPCR
000001XX
0D7H
00000000
T2CON
00000000
T2MOD
XXXXXX00
RCAP2L
00000000
RCAP2H
00000000
TL2
00000000
TH2
00000000
0C8H
0C0H
0B8H
0B0H
0A8H
0A0H
98H
0CFH
0C7H
0BFH
0B7H
0AFH
0A7H
9FH
IP
XX000000
P3
11111111
IE
SPSR
00XXXXXX
0X000000
P2
11111111
SCON
00000000
SBUF
XXXXXXXX
P1
11111111
WCON
00000010
90H
97H
TCON
00000000
TMOD
00000000
TL0
00000000
TL1
00000000
TH0
00000000
TH1
00000000
88H
8FH
P0
11111111
SP
00000111
DP0L
00000000
DP0H
00000000
DP1L
00000000
DP1H
00000000
SPDR
XXXXXXXX
PCON
0XXX0000
80H
87H
4-221
ATMEL [ ATMEL ]
