AT87C54X2-3CSUL View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT87C54X2-3CSUL

8-bit CMOS Microcontroller 16/32 Kbytes ROM/OTP

Atmel Corporation 

Figure 11-1. Power-Down Exit Waveform

INT0

INT1

XTAL1

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 inter-

rupt 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 11-1. The state of ports during idle and power-down modes

Mode

Program

Memory

ALE

PSEN

PORT0

Idle

Internal

1

1

Port Data*

Idle

External

1

1

Floating

Power Down Internal

0

0

Port Data*

Power Down External

0

0

Floating

* Port 0 can force a "zero" level. A "one" Level 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

30 AT/TS8xC54/8X2

4431E–8051–04/06

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