问题 阅读理解

阅读理解。

     Bicycles are very popular around the world today. People ride their bicycles for exercise and enjoyment.

In some places,people use a bicycle to get to work. In other places,bicycle riding is a very popular exercise

to people who live in cities. But who invented the first bicycle? In 1791, a Frenchman named Comte de

Sovran invented and owned the first bicycle. Mrs. Sovran rode (骑) the bicycle in Paris. The handles (把手)

and the seat were wooden. This bicycle was very difficult to move. A rider even had to pick up the front

wheel to change direction. Finally, the bicycle had no brakes for stopping or pedals for the feet! Riding a

bicycle was a great risk.

     In 1817, a German named Baronvon Drais de Sauer burn made the first bicycle better. The seat became

more comfortable. The wheel could now change direction. His ride in the forest took only one hour instead

of three hours on foot, which surprised people at that time.

      Sauer burn brought this kind of bicycle from Germany to France. Then Denis Johnson, an Englishman,

made a bicycle for women. It had space for their dresses to hang down. But these bicycles still had no brakes

or pedals,and riders often got hurt. These bicycles and the people who rode them were not very popular.

     It took another forty-five years for the bicycle to become popular. More than 100 years later, bicycle riding

is more popular than ever. In fact, in India and China, there are still many more bicycles than ears.

1. Which of the following best describes the first bicycle?

A. Very popular.

B. Easy to carry.

C. Ugly-looking.

D. Difficult to ride.

2. Why was it a risk to ride the first bicycle?

A. Because it had no pedals for the feet.

B. Because it was difficult to control (控制).

C. Because people would laugh at you.

D. Because handles and the seat were wooden.

3. Which of the following was not improved by Sauer burn to the first bicycle?

A. Brakes were added to it.

B. It was made to go faster.

C. The wheel could now change direction.

D. The seat was made more comfortable.

4. What's the major difference between Denis Johnson's bicycle and the earlier ones?

A. It was more comfortable.

B. It was faster and safer.

C. It had space for the rider's dress.

D. It had metal handles and seat.

5. The best title (题目) for the passage would be _______.

A. Bicycles Around the World

B. How to Ride a Bicycle

C. The Greatest Invention

D. The First Bicycle

答案

1-5      DBACD

问答题


阅读以下关于嵌入式系统软件设计方面的叙述,回答问题1至问题3。
某公司承担了一项嵌入式系统软件开发项目。该项目主要用于车载电子系统中监视发动机及燃油系统等系统工作状况,并通过综合仪表显示给驾驶员。经过多次与用户沟通,形成以下技术要求:
(1)本项目的硬件平台由主处理机模块和多种接口模块组成,底板采用标准VME总线(硬件结构图如图3-1所示),具体硬件模块配置如下。


①主处理机模块(CPM)采用PowerPC755,主频266MHz,配有SDRAM存储器和FLASH存储器;提供一个定时/计数器;支持16级中断和二级cache。
②输入输出模块(IOC)支持16路RS422接口信号,传输速率不低于115.2kbps,IOC模块与CPM模块的数据交换采用64KByte双端口存储器。
③离散量接口模块(DAM)支持64路开关型离散量输入输出接口;2路频率量输入;12位A/D转换器和12位:D/A转换器。
④图形处理模块(GPM)用于显示图形,支持OpenGL标准接口软件。
⑤MBI模块主要提供1553B外总线接口,PSM为电源支持模块。
(2)本项目软件主要工作在CPM模块中,完成对外部设备的数据采集、分析和相应的控制,将监视结果以图形方式显示给驾驶员。该系统的软件主要包括外部接口驱动软件、VME数据传输软件、处理软件、图形显示和外总线(1553B)数据交换软件。要求数据的采集必须确保每帧数据无丢失,并在本帧内完成数据的处理工作,本帧信息显示给驾驶员的时刻最晚不能超过下帧。详细的技术要求如下。
①16路RS422接口主要完成对汽车燃油系统、动力系统和驾驶员命令的数据采集与控制。RS422数据传输格式将以32Byte为基本数据块,分别以20ms、40ms、60ms和1s四个不同周期交换数据。
②64路离散量数据主要监控发动机工作状态,要求每10ms采集一次,并在下一个10ms周期内将发动机状况显示到驾驶员座舱。
③多路模拟量数据主要采集发动机转速、油量及汽车的其他数据,为驾驶员监控汽车状态提供必要的量化数据。模拟量数据的刷新频率为1s。
④外总线(1553B)主要完成该系统与汽车其他电子系统的数据交换。


公司将本项目交给项目主管李工实施,要求李工按技术要求完成本项目的软件设计工作,公司根据合同关于“数据的采集必须确保每帧数据无丢失,并在本帧内完成数据的处理工作,本帧信息显示给驾驶员的时刻最晚不能超过下帧”的要求,提醒李工设计中重点考虑整个系统的实时性问题。李工完成设计后,提交公司评审,会上就李工设计中存在的缺陷展开了激烈讨论,最终达成一致。

【问题3】
请用150字以内的文字说明针对IOC模块的多路RS422接口的数据采集,其驱动程序使用中断方式或查询方式的主要差别是什么主要优缺点有哪些

多项选择题