论文部分内容阅读
微型机的应用往往涉及到与多个外部设备或中断源的连接问题.这些中断源的中断信号一起接到微处理器(μP)的IRQ脚上但是μP本身无法分辨是哪个中断源来的中断信号.最简单的办法就是μP通过中断服务程序对各中断源依次查询,以确定是哪个中断源来的信号,然后转入相应的服务程序.这种办法当然是很慢的.为此有些半导体器件厂商生产一种专用蕊片:优先中断控制器(如Motorola的6828),对中断时μP给出的中断矢量地址自动进行修改,从而由μP的一个中断矢量地址派生出对应8个中断源的8个中断矢量地址.中断的优先等级由中断源连线的次序决
Microcomputer applications often involve connection problems with multiple external devices or interrupt sources whose interrupt signals are connected to the IRQ pin of the microprocessor (μP), but μP itself can not tell which one was the source of the interrupt Signal. The easiest way is to μP through the interrupt service routine for each interrupt source inquiries, to determine which interrupt source to the signal, and then transferred to the corresponding service routine. This approach is of course very slow. For this reason, some semiconductors Device manufacturers to produce a special chip: priority interrupt controller (such as the Motorola 6828), interrupted interrupt address μP given automatically modified to address the address of an interrupt vector μP derived from the corresponding eight interrupt sources 8 interrupt vector addresses. The interrupt priority level is determined by the sequence of interrupt source connections