AT89C51RD2 Datasheet, PDF (1/137 Pages) ATMEL Corporation – 8-bit Flash Microcontroller

Features
• 80C52 Compatible
– 8051 Instruction Compatible
– Six 8-bit I/O Ports (64 Pins or 68 Pins Versions)
– Four 8-bit I/O Ports (44 Pins Version)
– Three 16-bit Timer/Counters
– 256 Bytes Scratch Pad RAM
– 9 Interrupt Sources with 4 Priority Levels
• Integrated Power Monitor (POR/PFD) to Supervise Internal Power Supply
• ISP (In-System Programming) Using Standard V_CC Power Supply
• 2048 Bytes Boot ROM Contains Low Level Flash Programming Routines and a Default
Serial Loader
• High-speed Architecture
– In Standard Mode:
40 MHz (Vcc 2.7V to 5.5V, both Internal and external code execution)
60 MHz (Vcc 4.5V to 5.5V and Internal Code execution only)
– In X2 mode (6 Clocks/machine cycle)
20 MHz (Vcc 2.7V to 5.5V, both Internal and external code execution)
30 MHz (Vcc 4.5V to 5.5V and Internal Code execution only)
• 64K Bytes On-chip Flash Program/Data Memory
– Byte and Page (128 Bytes) Erase and Write
– 100k Write Cycles
• On-chip 1792 bytes Expanded RAM (XRAM)
– Software Selectable Size (0, 256, 512, 768, 1024, 1792 Bytes)
– 768 Bytes Selected at Reset for T89C51RD2 Compatibility
• On-chip 2048 Bytes EEPROM Block for Data Storage (AT89C51ED2 Only)
– 100K Write Cycles
• Dual Data Pointer
• Variable Length MOVX for Slow RAM/Peripherals
• Improved X2 Mode with Independent Selection for CPU and Each Peripheral
• Keyboard Interrupt Interface on Port 1
• SPI Interface (Master/Slave Mode)
• 8-bit Clock Prescaler
• 16-bit Programmable Counter Array
– High Speed Output
– Compare/Capture
– Pulse Width Modulator
– Watchdog Timer Capabilities
• Asynchronous Port Reset
• Full-duplex Enhanced UART with Dedicated Internal Baud Rate Generator
• Low EMI (Inhibit ALE)
• Hardware Watchdog Timer (One-time Enabled with Reset-Out), Power-off Flag
• Power Control Modes: Idle Mode, Power-down Mode
• Single Range Power Supply: 2.7V to 5.5V
• Industrial Temperature Range (-40 to +85°C)
• Packages: PLCC44, VQFP44, PLCC68, VQFP64, PDIL40
8-bit Flash
Microcontroller
AT89C51RD2
AT89C51ED2
Description
AT89C51RD2/ED2 is high performance CMOS Flash version of the 80C51 CMOS sin-
gle chip 8-bit microcontroller. It contains a 64-Kbyte Flash memory block for code and
for data.
The 64-Kbytes Flash memory can be programmed either in parallel mode or in serial
mode with the ISP capability or with software. The programming voltage is internally
generated from the standard V_CC pin.
Rev. 4235E–8051–04/04
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