Rainbow-electronics AT89C55WD Bedienungsanleitung PDF herunterladen (Seite 7)

AT89C55WD

1921B–MICRO–09/02

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.

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.

Table 2 . T2CON—Timer/Counter 2 Control Register

T2CON Address = 0C8H Reset Value = 0000 0000B

Bit Addressable

Bit TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2

CP/RL2

76543210

Table 3 . AUXR: Auxiliary Register

AUXR Address = 8EH Reset Value = XXX00XX0B

Not Bit Addressable

–––WDIDLE DISRTO ––DISALE

Bit 7 6 5 4 3 2 1 0

– Reserved for future expansion

DISALE 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

DISRTO Disable/Enable Reset out

DISRTO Operating Mode

0 Reset pin is driven High after WDT times out

1 Reset pin is input only

WDIDLE Disable/Enable WDT in IDLE mode

WDIDLE Operating Mode

0 WDT continues to count in IDLE mode

1 WDT halts counting in IDLE mode

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Rainbow-electronics AT89C55WD Bedienungsanleitung Seite 7