题目内容

“方式控制字”和“PC口按位置位/复位控制字”都可以写入82C55的同一控制寄存器,82C55是如何来区分这两个控制字的?

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判断下列说法是否正确,为什么?

A. 由于82C55不具有地址锁存功能,因此在与AT89S51的接口电路中必须加地址锁存器。
B. 在82C55芯片中,决定各端口编址的引脚是PA1和PA0。
C. 82C55具有三态缓冲器,因此可以直接挂在系统的数据总线上。
D. 82C55的PB口可以设置成方式2。

His ____as a soldier ended with injury to both eyes.

The only real ____China’s pollution problems, scientists claim, is to cut emissions (排放) from power plants, factories and cars.

The Chinese government has officially ____the global gambling industry, which makes it likely that Chinese citizens will be gambling much less in China, its neighboring countries, and the US.

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