Description
The AT89C51RB2/RC2 is a high-performance Flash version of the 80C51 8-bit microcontrollers. It contains a 16K or 32K Bytes Flash memory block for program and data.
The 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 VCC pin.
The AT89C51RB2/RC2 retains all features of the 80C52 with 256 Bytes of internal RAM, a 9-source 4-level interrupt controller and three timer/counters.

FEATUREs
• 80C52 Compatible
   – 8051 Pin and Instruction Compatible
   – Four 8-bit I/O Ports
   – Three 16-bit Timer/Counters
   – 256 Bytes Scratch Pad RAM
   – 9 Interrupt Sources with 4 Priority Levels
   – Dual Data Pointer
• Variable Length MOVX for Slow RAM/Peripherals
• ISP (In-system Programming) Using Standard VCC Power Supply
• Boot ROM Contains Low Level Flash Programming Routines and a Default Serial Loader
• High-speed Architecture
   – 48 MHz in Standard Mode and Internal Code Execution (40 MHz for external code)
   – 24 MHz in X2 Mode and internal code execution (20 MHz for external code)
   – 16K/32K 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)
   – 256 Bytes Selected at Reset for TS87C51RB2/RC2 Compatibility
• Keyboard Interrupt Interface on Port P1
• SPI Interface (Master/Slave Mode)
• 8-bit Clock Prescaler
• Improved X2 Mode with Independent Selection for CPU and Each Peripheral
• Programmable Counter Array 5 Channels
   – 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:
   – 2.7 to 3.6 (3V Version)
   – 2.7 to 5.5V (5V Version)
• Temperature Ranges: Commercial (0 to +70°C) and Industrial (-40°C to +85°C)
• Packages: PDIL40, PLCC44, VQFP44