AT89C51ED2-RDTUM datasheet(2/137 Pages) ATMEL

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4235K–8051–05/08

AT89C51RD2/ED2

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 pro-

vides 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.

Table 1-1.

Memory Size and I/O Pins

Package

Flash (Bytes)

XRAM (Bytes)

Total RAM (Bytes)

I/O

PLCC44/VQFP44

64K

1792

2048

PLCC68/VQFP64

64K

1792

2048

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