AT89C5122 ATMEL [ATMEL Corporation], AT89C5122 Datasheet - Page 181

• Manufacturer Part Number: AT89C5122
• Description: MICROCONTROLLER WITH USB AND SMART CARD READER INTERFACES
• Manufacturer: ATMEL [ATMEL Corporation]

Table State of Ports
Note:
Reduced EMI Mode
4202D–SCR–06/05
Power-down
Power-down
Mode
Idle
Idle
1. Port 0 can force a 0 level. A "one" will leave port floating.
Program Memory
External
External
Internal
Internal
XTAL1
INT0
INT1
ALE
1
1
0
0
Figure 109. Power-down Exit Waveform
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:
Table shows the state of ports during idle and power-down modes.
The ALE signal is used to demultiplex address and data buses on port 0 when used with
external program or data memory. Nevertheless, during internal code execution, ALE
signal is still generated. In order to reduce EMI, ALE signal can be disabled by setting
AO bit.
The AO bit is located in AUXR register at bit location 0. As soon as AO is set, ALE is no
longer output but remains active during MOVX and MOVC instructions and external
fetches. During ALE disabling, ALE pin is weakly pulled high.
Active phase
PSEN
1
1
0
0
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.
Port Data
Port Dat*
Floating
Floating
P0
(1)
Power-down phase
Port Data
Port Data
Port Data
Port Data
P1
Port Data
Port Data
Port Data
Address
P2
Oscillator restart phase
Port Data
Port Data
Port Data
Port Data
P3
Port Data
Port Data
Port Data
Port Data
Active phase
P4
Port Data
Port Data
Port Data
Port Data
P5
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