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分布式系统的一个重要问题是如何实现主机控制下的前端机复位,从而实现完全的主机控制.下面给出的两种电路便能在不改变串行口功能条件下,用串口实现主机控制下的前端机复位.其原理和电路介绍如下:电路一,其结构如图1示,在电路中以U1实现对串行通信信号的反相,R1,C1及U2实现对前端机的复位信号的检出,D1完成对C1的快速放电.工作原理如下:正常工作时串口作主机和前端机通信用,因设置的波特率较高(>1200),即使在发00的最坏情况下,C1 上充得的电压始终超不过门限值,因此,该复位电路不产生复位信号.当需要对前端机复位时,
Distributed system is an important issue is how to achieve the front-end host control reset in order to achieve complete host control. The following two circuits given will be able to change the serial port under the conditions of function, with the serial port to achieve host control The front end of the reset. The principle and circuit description is as follows: Circuit 1, the structure shown in Figure 1 shows, in the circuit to U1 reverse serial communication signal, R1, C1 and U2 to achieve the front-end reset signal Detected, D1 to complete the rapid discharge of C1. The working principle is as follows: Normal work for the serial port for the host and the front-end machine communication, due to the higher baud rate set (> 1200), even in the worst case of hair 00, The voltage charged on C1 always exceeds the threshold, therefore, the reset circuit does not generate a reset signal.When the front-end machine needs to be reset,