AT89C51ED2-RLTUM Atmel, AT89C51ED2-RLTUM Datasheet - Page 86

• Manufacturer Part Number: AT89C51ED2-RLTUM
• Description: IC 8051 MCU FLASH 64K 44VQFP
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51ED2-RLTUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 60MHz
• Connectivity: SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 2K 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
• Cpu Family: 89C
• Device Core: 8051
• Device Core Size: 8b
• Frequency (max): 40MHz
• Interface Type: SPI/UART
• Total Internal Ram Size: 2KB
• # I/os (max): 34
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: VQFP
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• 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
• Minimum Operating Temperature: - 40 C
• Package: 44VQFP
• Family Name: AT89
• Maximum Speed: 40 MHz
• For Use With: AT89OCD-01 - USB EMULATOR FOR AT8XC51 MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -
• Lead Free Status / Rohs Status: Compliant

20. ONCE
86
AT89C51RD2/ED2
®
Mode (ON- Chip Emulation)
The ONCE mode facilitates testing and debugging of systems using AT89C51RD2/ED2 without
removing the circuit from the board. The ONCE mode is invoked by driving certain pins of the
AT89C51RD2/ED2; the following sequence must be exercised:
While the AT89C51RD2/ED2 is in ONCE mode, an emulator or test CPU can be used to drive
the circuit. Table 20-1 shows the status of the port pins during ONCE mode.
Normal operation is restored when normal reset is applied.
Table 20-1.
Weak pull-
• Pull ALE low while the device is in reset (RST high) and PSEN is high.
• Hold ALE low as RST is deactivated.
ALE
up
Weak pull-
PSEN
External Pin Status During ONCE Mode
up
Port 0
Float
Weak pull-
Port 1
up
Weak pull-
Port 2
up
Weak pull-
Port 3
up
Port I2
Float
XTALA1/2
Active
4235K–8051–05/08
XTALB1/2
Active