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011800

FEATURES

8051-compatible microcontroller adapts to its

task

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32K, 64K, or 128K bytes of nonvolatile

SRAM for program and/or data storage

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In-system programming via on-chip serial

port

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Capable of modifying its own program or

data memory in the end system

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Provides separate Byte-wide bus for

peripherals

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Performs CRC-16 check of NV RAM

memory

High-reliability operation

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Maintains all nonvolatile resources for

over 10 years in the absence of power

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Power-fail reset

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Early Warning Power-fail Interrupt

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Watchdog Timer

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Lithium backed memory remembers

system state

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Precision reference for power monitor

Fully 8051-compatible

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128 bytes scratchpad RAM

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Two timer/counters

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On-chip serial port

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32 parallel I/O port pins

Permanently powered real time clock

PIN ASSIGNMENT

DESCRIPTION

The DS2251T 128k Soft Microcontroller Module is an 8051-compatible microcontroller module based on

nonvolatile RAM technology. It is designed for systems that need large quantities of nonvolatile memory.

Like other members of the Secure Microcontroller family, it provides full compatibility with the 8051

instruction set, timers, serial port, and parallel I/O ports. By using NV RAM instead of ROM, the user can

program, then reprogram the microcontroller while in-system. The application software can even change

its own operation. This allows frequent software upgrades, adaptive programs, customized systems, etc.

In addition, by using NV RAM, the DS2251T is ideal for data logging applications. The powerful real

time clock includes interrupts for time stamp and date. It keeps time to one-hundredth of seconds using its

onboard 32 kHz crystal.

DS2251(T)

128k Soft Microcontroller Module

www.dalsemi.com

72-Pin SIMM