单片机学习应用的六个重要部分

中文字数:2138,中文页数:3  英文字数:1357页数:3

A bus: We know that a circuit is always from the components connected through the wire in analog circuits, the connection does not become a problem because the devices are usually serial inter-relationship between the various devices connection, not many, but not the same as computer circuits, which is based on the microprocessor as the core, the device must be connected with the microprocessor, the device must be between the coordinated and so they need a lot of connections on If still the same as analog circuits, in the microprocessor and a separate connection between devices, while the number of lines will be more shocking, so the introduction of the microprocessor in the concept of a bus, all devices share the connection, all devices all the eight data lines from the eight common line, which is equivalent to all devices in parallel, but this is not enough alone, if there are two devices send data at the same time, a 0, a 1, then recipient received what is it? This is not allowed, there is a need to control through the control line so that devices work time, any time there can be only one device to send data (can have more than one receiving device at the same time). Data devices will be referred to as data bus, all the line of control devices known as the control bus. In the internal or external memory single-chip and other devices in the memory cell, the memory cell to be assigned addresses to use, the allocation of addresses is of course given in the form of electrical signals, and as a result of more storage units, so for address the allocation of more of the line, the line known as the address bus.

总线：我们知道，一个电路总是由元器件通过电线连接而成的，在模拟电路中，连线并不成为一个问题，因为各器件间一般是串行关系，各器件之间的连线并不很多，但计算机电路却不一样，它是以微处理器为核心，各器件都要与微处理器相连，各器件之间的工作必须相互协调，所以需要的连线就很多了，如果仍如同模拟电路一样，在各微处理器和各器件间单独连线，则线的数量将多得惊人，所以在微处理机中引入了总线的概念，各个器件共同享用连线，所有器件的8根数据线全部接到8根公用的线上，即相当于各个器件并联起来，但仅这样还不行，如果有两个器件同时送出数据，一个为0，一个为1，那么，接收方接收到的究竟是什么呢？这种情况是不允许的，所以要通过控制线进行控制，使器件分时工作，任何时候只能有一个器件发送数据（可以有多个器件同时接收）。器件的数据线也就被称为数据总线，器件所有的控制线被称为控制总线。在单片机内部或者外部存储器及其它器件中有存储单元，这些存储单元要被分配地址，才能使用，分配地址当然也是以电信号的形式给出的，由于存储单元比较多，所以，用于地址分配的线也较多，这些线被称为地址总线。

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