• 80C52 Compatible
– Four 8-bit I/O Ports
– Three 16-bit Timer/Counters
– 256 Bytes Scratch Pad RAM
– 8 Interrupt Sources with 4 Priority Levels
– Dual Data Pointer
• Variable Length MOVX for Slow RAM/Peripherals
• High-speed Architecture
– 10 to 40 MHz in Standard Mode
• 16K/32K Bytes On-Chip ROM Program
• AT80C51RD2 ROMless Versions
• On-Chip 1024 bytes Expanded RAM (XRAM)
– Software Selectable Size (0, 256, 512, 768, 1024 bytes)
– 256 Bytes Selected at Reset
• Keyboard Interrupt Interface on Port P1
• 8-bit Clock Prescaler
• 64K Program and Data Memory Spaces
• Improved X2 Mode with Independant Selection for CPU and Each Peripheral
• Programmable Counter Array 5 Channels with:
– High-speed Output
– Compare/Capture
– Pulse Width Modulator
– Watchdog Timer Capabilities
• Asynchronous Port Reset
• Full Duplex Enhanced UART
• Dedicated Baud Rate Generator for UART
• Low EMI (Inhibit ALE)
• Hardware Watchdog Timer (One-time Enabled with Reset-out)
• Power Control Modes
– Idle Mode
– Power-down Mode
– Power-off Flag
• Power Supply: 2.7V to 5.5V
• Temperature Ranges: Commercial (0 to +70°C) and Industrial (-40°C to +85°C)
• Packages: PDIL40, PLCC44, VQFP44
