
22
4428E–8051–02/08
AT/TS80C31X2
Figure 11-1. Power-Down Exit Waveform
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:
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
INT1
INT0
XTAL1
Power-down phase
Oscillator restart phase
Active phase
Mode
Program
Memory
ALE
PSEN
PORT0
PORT1
PORT2
PORT3
Idle
External
1
Floating
Port Data
Address
Port Data
Power Down
External
0
Floating
Port Data