DS2251 Datasheet, PDF (1/20 Pages) Dallas Semiconductor – 128k Soft Microcontroller Module

DS2251(T)
128k Soft Microcontroller Module
www.dalsemi.com
FEATURES
8051-compatible microcontroller adapts to its
task
- 32K, 64K, or 128K bytes of nonvolatile
SRAM for program and/or data storage
- In-system programming via on-chip serial
port
- Capable of modifying its own program or
data memory in the end system
- Provides separate Byte-wide bus for
peripherals
- Performs CRC-16 check of NV RAM
memory
High-reliability operation
- Maintains all nonvolatile resources for
over 10 years in the absence of power
- Power-fail reset
- Early Warning Power-fail Interrupt
- Watchdog Timer
- Lithium backed memory remembers
system state
- Precision reference for power monitor
Fully 8051-compatible
- 128 bytes scratchpad RAM
- Two timer/counters
- On-chip serial port
- 32 parallel I/O port pins
Permanently powered real time clock
PIN ASSIGNMENT
72-Pin SIMM
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.
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