ISA总线扩展板的原理及抗干扰措施

The Principle and Anti-Disturbance Ways of the Extended ISA Bus Board

本文在论及了总线主设备、从设备、总线操作周期等总线术语概念的基础上提出了当前最广泛流行的 ISA 总线延伸和扩展时的实际技术问题,给出了ISA 总线中输出、输入总线信号的实际延伸和扩展电路;详细论述了主机板CPU 和 DMA 控制器以及 I/O 插接板上 CPU 和 DMA 控制器等主设备分别占有 ISA 总线信号时的时序,总线信号方向控制的实际电路;最后叙述了延伸总线信号时的抗干扰措施。

Based on the discussion about main devices,auxiliary devices,operating cycle and other jargon of the bus,this pater brings out the practical problems of the most popular ISA bus when the bus is extended or expanded.It stats the time sequence that are occupied by CPU and DMA controller in either main board or I/O board,discusses the control of the bus sig- nals′ diretion in practical circuits.At last,the paper describes the way of anti-noise when the voltage bus signals are extended.