AT89C51RC2 Atmel Corporation, AT89C51RC2 Datasheet - Page 83

• Manufacturer Part Number: AT89C51RC2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RC2

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 1.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

Figure 34. Power-down Exit Waveform
Table 62. State of Ports
4180E–8051–10/06
Power Down
Power Down
Mode
Idle
Idle
or
XTALB
XTALA
INT0
INT1
Program Memory
Active Phase
External
External
Internal
Internal
be the one following the instruction that puts the AT89C51RB2/RC2 into Power-down
mode.
Exit from Power-down by reset redefines all the SFRs, exit from Power-down by exter-
nal interrupt does no affect the SFRs.
Exit from Power-down by either reset or external interrupt or keyboard interrupt does not
affect the internal RAM content.
Note:
Table 62 shows the state of ports during idle and power-down modes.
Port 0 can force a 0 level. A "one" will leave port floating.
ALE
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.
1
1
0
0
Power-down Phase
PSEN
1
0
0
1
Port Data
Port Data
Oscillator Restart Phase
PORT0
Floating
Floating
(1)
(1)
Port Data
Port Data
Port Data
Port Data
PORT1
AT89C51RB2/RC2
Active Phase
Port Data
Port Data
Port Data
PORT2
Address
Port Data
Port Data
Port Data
Port Data
PORT3
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