AT89LS51-16PI(2002) View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT89LS51-16PI
(Rev.:2002)

8-bit Low-Voltage Microcontroller with 4K Bytes In-System Programmable Flash

Atmel Corporation 

AT89LS51

User software should not write 1s to these unlisted locations, since they may be used in future

products to invoke new features. In that case, the reset or inactive values of the new bits will

always be 0.

Interrupt Registers: The individual interrupt enable bits are in the IE register. Two priorities

can be set for each of the five interrupt sources in the IP register.

Table 2. AUXR: Auxiliary Register

AUXR

Address = 8EH

Not Bit

Addressable

–

–

– WDIDLE DISRTO

–

Bit

7

6

5

4

3

2

Reset Value = XXX00XX0B

–

DISALE

1

0

–

DISALE

DISRTO

WDIDLE

WDIDLE

0

1

Reserved for future expansion

Disable/Enable ALE

DISALE

Operating Mode

0

ALE is emitted at a constant rate of 1/6 the oscillator frequency

1

ALE is active only during a MOVX or MOVC instruction

Disable/Enable Reset out

DISRTO

0

Reset pin is driven High after WDT times out

1

Reset pin is input only

Disable/Enable WDT in IDLE mode

WDT continues to count in IDLE mode

WDT halts counting in IDLE mode

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 appropriate value before accessing the

respective Data Pointer Register.

7

3053A–8051–05/02

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