AT89C51RE2-RLTUM Atmel, AT89C51RE2-RLTUM Datasheet - Page 119

• Manufacturer Part Number: AT89C51RE2-RLTUM
• Description: MCU 8051 128K FLASH 44-VQFP
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51RE2-RLTUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 60MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 8 KB
• Interface Type: UART, SPI
• Maximum Clock Frequency: 60 MHz
• Number Of Programmable I/os: 34
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: AT89OCD-01
• Minimum Operating Temperature: - 40 C
• Height: 1.45 mm
• Length: 10.1 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Width: 10.1 mm
• For Use With: AT89STK-11 - KIT STARTER FOR AT89C51RX2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details

Entering Power-Down
Mode
Exiting Power-Down
Mode
Figure 45. Power-Down Exit Waveform Using INT1:0#
7663E–8051–10/08
INT1:0#
OSC
To enter Power-Down mode, set PD bit in PCON register. The AT89C51RE2 enters the Power-
Down mode upon execution of the instruction that sets PD bit. The instruction that sets PD bit is
the last instruction executed.
Note:
There are two ways to exit the Power-Down mode:
1. Generate an enabled external interrupt.
Note:
Note:
2. Generate a reset.
Note:
Note:
Active phase
–
–
If VCC was reduced during the Power-Down mode, do not exit Power-Down mode until VCC is
restored to the normal operating level.
The external interrupt used to exit Power-Down mode must be configured as level sensitive
(INT0# and INT1#) and must be assigned the highest priority. In addition, the duration of the inter-
rupt must be long enough to allow the oscillator to stabilize. The execution will only resume when
the interrupt is deasserted.
Exit from power-down by external interrupt does not affect the
During the time that execution resumes, the internal RAM cannot be accessed; however, it is pos-
sible for the Port pins to be accessed. To avoid unexpected outputs at the Port pins, the instruction
immediately following the instruction that activated the Power-Down mode should not write to a
Port pin or to the external RAM.
Exit from power-down by reset redefines all the
content.
The AT89C51RE2 provides capability to exit from Power-Down using INT0#, INT1#.
Hardware clears PD bit in PCON register which starts the oscillator and restores the
clocks to the CPU and peripherals. Using INTx# input, execution resumes when the
input is released (see Figure 45). Execution resumes with the interrupt service
routine. Upon completion of the interrupt service routine, program execution
resumes with the instruction immediately following the instruction that activated
Power-Down mode.
A logic high on the RST pin clears PD bit in PCON register directly and
asynchronously. This starts the oscillator and restores the clock to the CPU and
peripherals. Program execution momentarily resumes with the instruction
immediately following the instruction that activated Power-Down mode and may
continue for a number of clock cycles before the internal reset algorithm takes
control. Reset initializes the AT89C51RE2 and vectors the CPU to address 0000h.
Power-down phase
Oscillator restart phase
SFRs
, but does not affect the internal RAM
SFRs
Active phase
nor the internal RAM content.
AT89C51RE2
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