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1、,电子信息专业英语 Unit 8 Microcontrollers,大连理工大学出版社,Contents,Text,Microcontrollers,The AT89C51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K bytes of Flash programmable and erasable read only memory (PEROM). By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel
2、AT89C51 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications.,微处理器 AT89C51是一种低功耗、高性能的带有4KB可编程和可擦除的只读存储器(PEROM)。 CMOS 8位微控制器，通过把通用的8位CPU与Flash内存集成在一块单芯片上，AT89C51是一种功能强大的微控制器，它为许多嵌入式控制应用提供了具有高度灵活性且价格低廉的解决方案。,microcontroller n.
3、 微处理器 (在本文中可以译成单片机) CMOS 是Complementary Metal Oxide Semiconductor缩写,指互补金属氧 化物(PMOS管和NMOS管)半导体共同构成的互补型MOS集成电路 制造工艺,它的特点是低功耗 programmable a. 可设计的, 可编程的 erasable a. 可消除的, 可抹去的 versatile a. 多用途的,多功能的 monolithic n. 单片电路, 单块集成电路 flexible a. 柔韧性, 易曲的, 可通融的 cost-effective a. 有成本效益的,划算的 embedded a. 植入的, 深入的,
4、 内含的,,Company Logo,Text,The AT89C51 provides the following standard features, 4K bytes of Flash 128 bytes of RAM, 32 I/O lines, 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 AT89C51 is de
5、signed with static logic for operation down to zero frequency and supports two software selectable power saving modes.,AT89C51具有以下标准特点：4KB闪存、128字节RAM、32个I/O、2个16位定时器/计数器、五个2级中断结构、全双工串行端口、片内振荡器和时钟电路。此外，AT89C51具有降到零频率的静态逻辑，以及支持两种软件可选的省电模式。,interrupt n. 发给电脑的中断信号 duplex a. 双倍的,复式的双工的,双向的 circuitry n. 电
6、路, 线路,,Company Logo,Text,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.,闲置模式可以停止CPU的同
7、时而允许RAM、定时器/计数器、串行端口和中断系统继续运行；掉电模式时保存RAM的内容、冻结振荡器以禁用芯片的所有其他功能，直至下一次硬件复位。 89C51有4个I/O端口，它们是P0口、P1口、P2口和P3口。,89C51 has 4 I/O ports, they are port 0, port 1, port 2 and port 3.,idle a. 空闲的, 懒惰的, 停顿的,,Company Logo,Text,Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin ca
8、n sink eight TTL inputs. When 1s are written to Port 0 pins, the pins can be used as high impedance inputs. In this mode P0 has internal pull-ups. Port 0 also receives the code bytes during Flash programming, and outputs the code bytes during program verification. External pull-ups are required duri
9、ng program verification.,P0口是一个8位漏极开路的双向I/O端口。作输出口时，每个引脚可以驱动8个TTL负载。当向P0口引脚写“1”时，则引脚可以被用来作为高阻抗输入。在访问外部程序存储器和数据存储器时，P0口也可以被指定为低字节地址和数据总线的复用，在此模式下P0有内部上拉电阻。在闪存编程时P0口接收指令字节；而在校验程序时，输出代码字节核查。在编程校验时，要求外接上拉电阻。,Port 0 may also be configured to be the multiplexed low order address/data bus during accesses t
10、o external program memory and data memory.1,在访问外部程序存储器和外部数据存储器时,P0口也可以被指定为低字节地址/数据总线的复用 本句中技术专有名词比较多:“Port 0”通常翻译为“P0口”;“low order address/data bus”译为“低字节数据/地址总线”;“external program memory”译为“外部程序存储器”;“(external) data memory”译为“(外部)数据存储器”,high impedance 高阻抗 programming n. 编程 verification n. 验证,,Compa
11、ny Logo,Text,Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. 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-ups and can be used as inputs. As inputs, Port 1 pins that are externally being pul
12、led low will source current (IIL) because of the internal pull-ups. Port 1 also receives the low-order address bytes during Flash programming and verification.,P1口是一个带有内部上拉电阻的8位双向I/O端口。P1口的输出缓冲器可以驱动4个TTL输入。当向P1口引脚写“1”时，通过内部的上拉电阻把端口拉到高电位，这时可用作输入口。作为输入口使用时，由于有内部的上拉电阻，P1被外部信号拉低的引脚将会输出电流(IIL)。在进行Flash编程
13、和校验时，P1口接收低8位地址。,,Company Logo,Text,Port 2 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that a
14、re externally being pulled low will source current (IIL) because of the internal pull-ups.,P2口是一个带有内部上拉电阻的8位双向I/O端口。P2的输出缓冲器可驱动（吸收/输出电流）4个TTL输入。对P2口写“1”时，通过内部上拉电阻把端口拉到高电位，这时可用作输入口。P2作输入口使用时，因为有内部上拉电阻，那些被外部信号拉低的引脚会输出一个电流(IIL)。,,Company Logo,Text,(MOVX DPTR). In this application, it uses strong intern
15、al pull-ups when emitting 1s. During accesses to external data memory that uses 8-bit addresses (MOVXRI), 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.,在从外部程序存储器取指令和访问外部数据存储器(如执行“MOVX DPTR”指令)期间,当使用16位地址时,P2输出高8位地址。当送出“1S”信息时,本器件采用的是较大内部上拉电阻，在访问8位地址的外部数据存储器(如执行“MOVX RI”指令)时,P2口输出P2特殊功能寄存器的内容。在对Flash ROM 编程和程序检验期间,P2也接收高位地址和一些控制信号。,Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data me
