AT89C51RB2-SLSIM Atmel, AT89C51RB2-SLSIM Datasheet - Page 79

• Manufacturer Part Number: AT89C51RB2-SLSIM
• Description: IC 8051 MCU FLASH 16K 44PLCC
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51RB2-SLSIM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 60MHz
• Connectivity: SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-PLCC
• For Use With: AT89STK-11 - KIT STARTER FOR AT89C51RX2
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

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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