AT  -  Series DataSheet
T89C51RD2  -  0 to 40 MHz Flash Programmable 8-bit Microcontroller  -  Atmel  -  8051

Features
• 80C52 Compatible
– 8051 Pin and Instruction Compatible
– Four 8-bit I/O Ports (or 6 in 64/68 Pins Packages)
– Three 16-bit Timer/Counters
– 256 bytes Scratch Pad RAM
– 7 Interrupt Sources With 4 Priority Levels
• ISP (In-System Programming) Using Standard VCC Power Supply
• Boot Flash Contains Low Level Flash Programming Routines and a Default Serial Loader
• High-Speed Architecture
– 40 MHz in Standard Mode
– 20 MHz in X2 Mode (6 Clocks/Machine Cycle)
• 64K bytes On-chip Flash Program/Data Memory
– Byte and Page (128 bytes) Erase and Write
– 100K Write Cycles
• On-chip 1024 Bytes Expanded RAM (XRAM)
– Software Selectable Size (0, 256, 512, 768, 1024 bytes)
– 768 Bytes Selected at Reset for T87C51RD2 Compatibility
• Dual Data Pointer Variable Length MOVX for Slow RAM/Peripherals
• Improved X2 Mode with Independant Selection for CPU and Each Peripheral
• 2K bytes EEPROM Block for Data Storage
– 100K Write Cycle
• Programmable Counter Array with
– High Speed Output
– Compare/Capture
– Pulse Width Modulator
Watchdog Timer Capabilities
Asynchronous Port Reset
Full-duplex Enhanced UART
Low EMI (Inhibit ALE)
– Hardware Watchdog Timer (One-time Enabled with Reset-out)
• Power Control Modes:
– Idle Mode
– Power-down Mode
• Power Supply:
– M version: Commercial and Industrial
4.5V to 5.5V: 40 MHz (X1 Mode), 20 MHz (X2 Mode)
3V to 5.5V: 33 MHz (X1 Mode), 16 MHz (X2 Mode)
– L version: Commercial and industrial
2.7V to 3.6V: 25 MHz (X1 Mode), 12 MHz (X2 Mode)
• Temperature Ranges: Commercial (0 to +70°C) and Industrial (-40 to +85°C)
• Packages: PDIL40, PLCC44, VQFP44, PLCC68, VQFP64