AT83C51RB2-3CSCM View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT83C51RB2-3CSCM

80C51 High Performance ROM 8-bit Microcontroller

Atmel Corporation 

Figure 22. Power-down Exit Waveform

INT0

INT1

XTAL

Active Phase

Power-down Phase

OscillatoR Restart Phase

Active Phase

Exit from power-down by reset redefines all the SFRs, exit from power-down by external

interrupt does no affect the SFRs.

Exit from power-down by either reset or external interrupt does not affect the internal

RAM content.

Note:

If idle mode is activated with power-down mode (IDL and PD bits set), the exit sequence

is unchanged, when execution is vectored to interrupt, PD and IDL bits are cleared and

idle mode is not entered.

Table 43 shows the state of ports during idle and power-down modes.

Table 43. State of Ports

Mode

Program Memory

ALE

PSEN

PORT0

Idle

Internal

1

1

Port Data(1)

Idle

External

1

1

Floating

Power-down

Internal

0

0

Port Dat(1)

Power-down

External

0

0

Floating

Note: 1. Port 0 can force a 0 level. A "one" will leave port floating.

PORT1

Port Data

Port Data

Port Data

Port Data

PORT2

Port Data

Address

Port Data

Port Data

PORT3

Port Data

Port Data

Port Data

Port Data

60 AT80C51RD2/AT83C51Rx2

4113B–8051–03/05

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