1、 专业文献翻译 题 目 : AT89C51 的介绍 姓 名 : 学 院 : 专 业 : 电子信息科学与技术 班 级 : 班 学 号 : 指 导教师 : 职称 : 20 年 月 日 南京农业大学教务处制 2008 届电子信息科学与技术专业毕业设计外文翻 译 1 原文： The Introduction of AT89C51 Description The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read on
2、ly memory (PEROM). The device is manufactured using Atmels high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By c
3、ombining 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 applications. Function characteristic The AT89C51 provides the following standard features: 4K bytes of
4、Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, one 5 vector two-level interrupt architecture, a full duplex serial port, one-chip oscillator and clock circuitry. In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports two software s
5、electable 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 hardware reset. Pin Desc
6、ription VCC： Supply voltage. GND： Ground. 2008 届电子信息科学与技术专业毕业设计外文翻 译 2 Port 0 Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance inputs. Port 0 may also be configured
7、 to be the multiplexed address/data bus during accesses to external program and data memory. In this mode P0 has internal Pull-up resistor. Port 0 also receives the code bytes during Flash programming, and outputs the code bytes during Program verification. External Pull-up resistors are required du
8、ring Program verification. Port 1 Port 1 is an 8-bit bi-directional I/O port with internal Pull-up resistors. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins they are pulled high by the internal Pull-up resistors and can be used as inputs. As inputs, Por
9、t 1 pins that are externally being pulled low will source current (IIL) because of the internal Pull-up resistors. Port 1 also receives the low-order address bytes during Flash programming and verification. Port 2 Port 2 is an 8-bit bi-directional I/O port with internal Pull-up resistor. The Port 2
10、output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins they are pulled high by the internal Pull-up resistor and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current, because of the internal Pull-up resistor. Port 2 emits
11、the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses. In this application, it uses strong internal Pull-up resistor when emitting 1s. During accesses to external data memory that use 8-bit addresses, Port 2 emits the contents of the P2 Special Function Register. Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.
