Datasheet

71M6521DE/DH/FE Data Sheet
Page: 20 of 107 Rev 3
Special Function Registers (Generic 80515 SFRs)
Table 8 shows the location of the SFRs and the value they assume at reset or power-up.
Name Location Reset value Description
P0
0x80
0xFF
Port 0
SP
0x81
0x07
Stack Pointer
DPL
0x82
0x00
Data Pointer Low 0
DPH
0x83
0x00
Data Pointer High 0
DPL1
0x84
0x00
Data Pointer Low 1
DPH1
0x85
0x00
Data Pointer High 1
WDTREL
0x86
0x00
Watchdog Timer Reload register
PCON
0x87
0x00
UART Speed Control
TCON
0x88
0x00
Timer/Counter Control
TMOD
0x89
0x00
Timer Mode Control
TL0
0x8A
0x00
Timer 0, low byte
TL1
0x8B
0x00
Timer 1, high byte
TH0
0x8C
0x00
Timer 0, low byte
TH1
0x8D
0x00
Timer 1, high byte
CKCON
0x8E
0x01
Clock Control (Stretch=1)
P1
0x90
0xFF
Port 1
DPS
0x92
0x00
Data Pointer select Register
S0CON
0x98
0x00
Serial Port 0, Control Register
S0BUF
0x99
0x00
Serial Port 0, Data Buffer
IEN2
0x9A
0x00
Interrupt Enable Register 2
S1CON
0x9B 0x00 Serial Port 1, Control Register
S1BUF
0x9C
0x00
Serial Port 1, Data Buffer
S1RELL
0x9D
0x00
Serial Port 1, Reload Register, low byte
P2
0xA0
0x00
Port 2
IEN0
0xA8
0x00
Interrupt Enable Register 0
IP0
0xA9
0x00
Interrupt Priority Register 0
S0RELL
0xAA
0xD9
Serial Port 0, Reload Register, low byte
IEN1
0xB8
0x00
Interrupt Enable Register 1
IP1
0xB9
0x00
Interrupt Priority Register 1
S0RELH
0xBA
0x03
Serial Port 0, Reload Register, high byte
S1RELH
0xBB
0x03
Serial Port 1, Reload Register, high byte
USR2
0xBF
0x00
User 2 Port, high address byte for MOVX@Ri
IRCON
0xC0
0x00
Interrupt Request Control Register
T2CON
0xC8
0x00
Polarity for INT2 and INT3
PSW
0xD0
0x00
Program Status Word
WDCON
0xD8
0x00
Baud Rate Control Register (only WDCON.7 bit used)
A
0xE0
0x00
Accumulator
B
0xF0
0x00
B Register
Table 8: Special Function Registers Reset Values