The DS2250(T) soft microcontroller module is a fully 8051-compatible 8-bit CMOS microcontroller that offers "softness" in all aspects of its application. This is accomplished through the comprehensive use of nonvolatile technology to preserve all information in the absence of system VCC. The internal program/data memory space is implemented using 8, 32, or 64kB of nonvolatile CMOS SRAM. Furthermore, internal data registers and key configuration registers are also nonvolatile. An optional real-time clock gives permanently powered timekeeping. The clock keeps time to a hundredth of a second using an on-board crystal. All nonvolatile memory and resources are maintained for over 10 years at room temperature in the absence of power. * 8-bit 8051-Compatible Microcontroller Adapts to Task-At-Hand: * 8, 32, or 64kB of NV RAM for Program and/or Data Memory Storage * Initial Downloading of Software in End System via On-Chip Serial Port * Capable of Modifying its own Program and/or Data Memory in End Use * High-Reliability Operation: * Maintains all Nonvolatile Resources for 10 Years in the Absence of VCC * Power-Fail Reset * Early Warning Power-Fail Interrupt * Watchdog Timer * Software Security Feature: * Executes Encrypted Software to Prevent Unauthorized Disclosure * On-Chip, Full-Duplex Serial I/O Ports * Two On-Chip Timer/Event Counters * 32 Parallel I/O Lines * Compatible with Industry Standard 8051 Instruction Set * Permanently Powered Real-Time Clock