系统核心：AT89C51 特性 • 与MCS-51 产品兼容 • 在系统内有可编程的4KB闪存 • 耐久性: 1,000 写/擦除周期 • 全静态工作: 0 Hz－24 MHz • 三级程序存储器保密 • 128 x 8字节的内部RAM • 32 条可编程I/O 线 • 两个16 位的定时/计数器 • 六个中断源 • 空闲模式和掉电方式 AT89C51是一个带有4K字节闪速可编程可擦写只读存储器(EEPROM)的低压、高性能8位CMOS微型计算机。它采用ATMEL的高密非易失存储技术制造并和工业标准MC-51指令集和引脚结构兼容。通过在单块芯片上组合通用的CPU和闪速存储器，ATMEL89C51是一个强劲的微型机算计，它对许多嵌入式控制应用提供一高度灵活和成本低的解决办法。本多功能打铃设计应用AT89单片机的中断定时系统，进行定时、时间设置、打铃等功能，是嵌入系统的一个典型应用。 关键字：嵌入系统 AT89 多功能打铃 AT89C51 Features • Compatible with MCS-51™ Products • 4K Bytes of In-System Reprogrammable Flash Memory • Fully Static Operation: 0 Hz to 24 MHz • Three-level Program Memory Lock • 128 x 8-bit Internal RAM • 32 Programmable I/O Lines • Two 16-bit Timer/Counters • Six Interrupt Sources • Programmable Serial Channel • Low-power Idle and Power-down Modes The AT89C51 is a low-power， high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip，the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applic- ations
