题目内容

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。

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