jlmao-微机原理-ch7-中断系统-part1[1]

1、2005-04-26Kunming University of Science & Technology1Kunming University of Science & TechnologyPage 22005-04-26Kunming University of Science & TechnologyPage 32005-04-26Kunming University of Science & TechnologyPage 42005-04-26Kunming University of Science & TechnologyPage 52005-

2、04-26Kunming University of Science & TechnologyPage 62005-04-26Kunming University of Science & TechnologyPage 72005-04-264#0#1#INT n指令指令INTO指令指令除法除法出错出错单步单步(TF=1)非屏蔽中断非屏蔽中断中断逻辑中断逻辑INTR8259A2# NMI可可屏屏蔽蔽中中断断n#内部中断内部中断8086/8088 中断源中断源Kunming University of Science & TechnologyPage 82005-04-2

3、6Kunming University of Science & TechnologyPage 92005-04-26注意：这三种软件中断都是不可屏蔽中断。注意：这三种软件中断都是不可屏蔽中断。Kunming University of Science & TechnologyPage 102005-04-26Kunming University of Science & TechnologyPage 112005-04-26Kunming University of Science & TechnologyPage 122005-04-26由由CPU自动完成。

4、自动完成。Kunming University of Science & TechnologyPage 132005-04-26Kunming University of Science & TechnologyPage 142005-04-26以上过程中除了中断服务子程序需用户编程实现外，以上过程中除了中断服务子程序需用户编程实现外，其它部分均由其它部分均由CPU的中断机制自动完成。的中断机制自动完成。Kunming University of Science & TechnologyPage 152005-04-26对不可屏蔽中断对不可屏蔽中断即使即使IF = 0，

5、由，由NMI引脚进入的中断请求，引脚进入的中断请求，CPU也照常可响也照常可响应应 。软件中断软件中断不受不受IF标志的影响标志的影响 Kunming University of Science & TechnologyPage 162005-04-26Kunming University of Science & TechnologyPage 172005-04-26Kunming University of Science & TechnologyPage 182005-04-26Kunming University of Science & Technol

6、ogyPage 192005-04-26Kunming University of Science & TechnologyPage 202005-04-26Kunming University of Science & TechnologyPage 212005-04-26Kunming University of Science & TechnologyPage 222005-04-26注意：此处强调中断时硬件动作的时间配合。注意：此处强调中断时硬件动作的时间配合。Kunming University of Science & TechnologyPage

7、232005-04-26P291 图图8-6 8086/8088中断响应总线周期的时序中断响应总线周期的时序第第1个个INTA周期周期CLKT1 T2 T3 T4 T1 T2 T3 T4第第2个个INTA周期周期ALELOCKINTA中断类型号中断类型号D7D0Kunming University of Science & TechnologyPage 242005-04-26Kunming University of Science & TechnologyPage 252005-04-26多中断源时要考虑中断优先级及中断嵌套问题多中断源时要考虑中断优先级及中断嵌套问题 Ku

8、nming University of Science & TechnologyPage 262005-04-26通常在矢量中断中，通常在矢量中断中，IR0的优先级最高，的优先级最高，IR7最低。最低。（8259A） Kunming University of Science & TechnologyPage 272005-04-26Kunming University of Science & TechnologyPage 282005-04-26Kunming University of Science & TechnologyPage 292005-04-26Kunming University of Science &