8098单片机支持多机通讯,图1是基本结构.但在工业控制中,经常以IBM-PC机或其兼容机为上位机,与多个8098下位机进行串行通讯,构成多机系统.在应用中必须解决两个问题.一个是电平转换,因上位机的RS-232C电平标准为负逻辑;另一个是隔离,以避免因曾有下位机故障而导致昂贵的上位机损坏.在多机系统中,各机之间隔离非常重要.图2是1台IBMPC机与4片8098单片机通讯的电路,该电路能够同时解决上述两个问题.这个电路主要使 8098 supports multi-machine communication, Figure 1 is the basic structure, but in industrial control, often with IBM-PC or compatible machine for the host computer, with a number of 8098 lower computer serial communication to form a multi-machine system. Two problems must be solved in the application: one is level shifting because the RS-232C level standard of the host computer is negative logic; the other is isolation, so as to avoid the damage of the expensive host computer caused by the failure of the lower computer. Multi-machine system, the isolation between the various machines is very important Figure 2 is a IBMPC machine and four 8098 microcontroller communication circuit, the circuit can solve both the above problems. This circuit is mainly used