分类：
2010-11-17 13:47:50
① Select communication
Since the control signal is relatively simple, this uses the serial communication. Used in this way was easier, less demanding on the peripheral device, half / full duplex mode can be free to choose. In the asynchronous method is the most important baud rate setting. Too high, will increase the burden on the microcontroller, or even not realized; too low, it will affect the response speed of the whole operation.
② transmission standard chosen
Transmission standards, now in a lot, but have advantages and disadvantages. System for the distribution of light in the studio, all kinds of audio, a lot of electrical interference, therefore, the selected transmission mode should be relatively strong anti-interference. This consideration, the communication distance of tens of meters to kilometers on, the selection of RS485 bus transfer is ideal. 485 using two transmission lines, to balance the transmission and differential receiver, so it has the ability to suppress common mode interference, plus the receiver has high sensitivity, can detect voltages as low as 200mV, it can greatly enhance the transmission of anti-jamming capability , the transmission signal is available outside the resumption of kilometers.
RS485 bus, easy to use, with a twisted pair to constitute a multi-station network of distributed systems. Its simple equipment, low cost, capable of long distance communications, it is obtained in the project a wide range of applications.
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