文档介绍：The Description of AT89S51 1 General Description The AT89S51 isa low-power, high-performance CMOS 8-bit microcontroller with 4K bytes of In-System Programmable Flash memory. The device is manufactured using Atmel ’s high-density nonvolatile memory technology and patible with the industry-standard 80C51 instruction set and p in out. The on-chip Flash allows the program memory tobe reprogrammed in-system orbya conventional nonvolatile memory programmer. bining a versatile 8-bit CPU with In-System Programmable Flash ona monolithic chip, the Atmel AT89S51 isa powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. The AT89S51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, two 16-bit timer/counters, a five-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next external interrupt or hardware re