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AT89C51ED2  -  8-bit Flash Microcontroller  -  Atmel  -  8051

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 VCC 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
Description
AT89C51RD2/ED2 is high performance CMOS Flash version of the 80C51 CMOS single 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 VCC pin.
The AT89C51RD2/ED2 retains all of the features of the Atmel 80C52 with 256 bytes of internal RAM, a 9-source 4-level interrupt controller and three timer/counters. The AT89C51ED2 provides 2048 bytes of EEPROM for nonvolatile data storage.
In addition, the AT89C51RD2/ED2 has a Programmable Counter Array, an XRAM of 1792 bytes, a Hardware Watchdog Timer, SPI interface, Keyboard, a more versatile serial channel that facilitates multiprocessor communication (EUART) and a speed improvement mechanism (X2 Mode).
The fully static design of the AT89C51RD2/ED2 allows to reduce system power consumption by bringing the clock frequency down to any value, including DC, without loss of data.
The AT89C51RD2/ED2 has 2 software-selectable modes of reduced activity and an 8-bit clock prescaler for further reduction in power consumption. In the Idle mode the CPU is frozen while the peripherals and the interrupt system are still operating. In the Power-down mode the RAM is saved and all other functions are inoperative.
The added features of the AT89C51RD2/ED2 make it more powerful for applications that need pulse width modulation, high speed I/O and counting capabilities such as alarms, motor control, corded phones, and smart card readers.