AT89S52-33AC ATMEL Corporation, AT89S52-33AC Datasheet - Page 7

• Manufacturer Part Number: AT89S52-33AC
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL Corporation

Table 3a. AUXR: Auxiliary Register
Dual Data Pointer Registers: To facilitate accessing both
internal and external data memory, two banks of 16-bit
Data Pointer Registers are provided: DP0 at SFR address
locations 82H-83H and DP1 at 84H-85H. Bit DPS = 0
in SFR AUXR1 selects DP0 and DPS = 1 selects DP1.
The user should always initialize the DPS bit to the
Table 3b. AUXR1: Auxiliary Register 1
AUXR
–
DISALE
DISRTO
WDIDLE
AUXR1
–
DPS
Reserved for future expansion
Disable/Enable ALE
DISALE
0
1
Disable/Enable Reset out
DISRTO
0
1
Disable/Enable WDT in IDLE mode
WDIDLE
0
1
Reserved for future expansion
Data Pointer Register Select
DPS
0
1
Address = 8EH
Not Bit Addressable
Address = A2H
Not Bit Addressable
Bit
Bit
Operating Mode
ALE is emitted at a constant rate of 1/6 the oscillator frequency
ALE is active only during a MOVX or MOVC instruction
Reset pin is driven High after WDT times out
Reset pin is input only
WDT continues to count in IDLE mode
WDT halts counting in IDLE mode
Selects DPTR Registers DP0L, DP0H
Selects DPTR Registers DP1L, DP1H
–
7
–
7
–
6
–
6
–
5
–
5
WDIDLE
4
–
4
appropriate value before accessing the respective Data
Pointer Register.
Power Off Flag: The Power Off Flag (POF) is located at bit
4 (PCON.4) in the PCON SFR. POF is set to “1” during
power up. It can be set and rest under software control and
is not affected by reset.
DISRTO
3
–
3
–
2
–
2
Reset Value = XXXXXXX0B
Reset Value = XXX00XX0B
–
1
–
1
DISALE
DPS
0
0
7