AT89C55WD-33JC(2002) View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT89C55WD-33JC
(Rev.:2002)

8-bit Microcontroller with 20K Bytes Flash

Atmel Corporation 

AT89C55WD

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

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

Table 2. T2CON—Timer/Counter 2 Control Register

T2CON Address = 0C8H

Bit Addressable

Bit

TF2

EXF2

RCLK

TCLK

7

6

5

4

EXEN2

3

Reset Value = 0000 0000B

TR2

C/T2

CP/RL2

2

1

0

Table 3. AUXR: Auxiliary Register

AUXR

Address = 8EH

Not Bit Addressable

–

–

Bit

7

6

–

WDIDLE DISRTO

5

4

3

Reset Value = XXX00XX0B

–

–

DISALE

2

1

0

–

DISALE

DISRTO

WDIDLE

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

Operating Mode

0

Reset pin is driven High after WDT times out

1

Reset pin is input only

Disable/Enable WDT in IDLE mode

WDIDLE Operating Mode

0

WDT continues to count in IDLE mode

1

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.

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.

7

1921B–MICRO–09/02

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