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Atmel AT89C51ID2 Data Sheet - Keil

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4289A–8051–09/03<br />

<strong>AT89C51ID2</strong><br />

pins, the instruction immediately following the instruction that activated the Power-Down<br />

mode should not write to a Port pin or to the external RAM.<br />

Note: Exit from power-down by reset redefines all the SFRs, but does not affect the internal<br />

RAM content.<br />

Table 56. Pin Conditions in Special Operating Modes<br />

Mode Port 0 Port 1 Port 2 Port 3 Port 4 ALE PSEN#<br />

Reset Floating High High High High High High<br />

Idle<br />

(internal<br />

code)<br />

Idle<br />

(external<br />

code)<br />

Power-<br />

Down(inter<br />

nal code)<br />

Power-<br />

Down<br />

(external<br />

code)<br />

<strong>Data</strong> <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> High High<br />

Floating <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> High High<br />

<strong>Data</strong> <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> Low Low<br />

Floating <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> <strong>Data</strong> Low Low<br />

75

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