AT89C51RC2-RLTIL Atmel, AT89C51RC2-RLTIL Datasheet - Page 79

• Manufacturer Part Number: AT89C51RC2-RLTIL
• Description: 8-bit Microcontrollers - MCU 80C31 w/4k
• Manufacturer: Atmel

Specifications of AT89C51RC2-RLTIL

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 60 MHz
• Program Memory Size: 32 KB
• Data Ram Size: 1280 B
• On-chip Adc: No
• Operating Supply Voltage: 2.7 V to 5.5 V
• Package / Case: VQFP-44
• Mounting Style: SMD/SMT
• Interface Type: SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Program Memory Type: Flash
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 2.7 V

ONCE
Chip Emulation)
4180E–8051–10/06
™
Mode (ON
The ONCE mode facilitates testing and debugging of systems using AT89C51RB2/RC2
without removing the circuit from the board. The ONCE mode is invoked by driving cer-
tain pins of the AT89C51RB2/RC2; the following sequence must be exercised:
•
•
While the AT89C51RB2/RC2 is in ONCE mode, an emulator or test CPU can be used to
drive the circuit. Table 61 shows the status of the port pins during ONCE mode.
Normal operation is restored when normal reset is applied.
Table 61. External Pin Status during ONCE Mode
Weak pull-up
Pull ALE low while the device is in reset (RST high) and PSEN is high.
Hold ALE low as RST is deactivated.
ALE
Weak pull-up
PSEN
Port 0
Float
Weak pull-up
Port 1
Weak pull-up
AT89C51RB2/RC2
Port 2
Weak pull-up
Port 3
XTAL1/2
Active
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