jlmao-微机原理-ch7-中断系统-part2

1、Kunming University of Science & TechnologyPage 2Kunming University of Science & TechnologyPage 3Kunming University of Science & TechnologyPage 4Kunming University of Science & TechnologyPage 5图图8 11(a) 8259A芯片引脚芯片引脚12345678910111213142827262524232221201918171615VccA0INTAIR7IR6IR5IR4I

2、R3IR2IR1IR0INTSP/ENCAS2CSWRRDD7D6D5D4D3D2D1D0CAS0CAS1Vss8259AKunming University of Science & TechnologyPage 6Kunming University of Science & TechnologyPage 7Kunming University of Science & TechnologyPage 8数据数据总线总线缓冲器缓冲器读读/写写逻辑逻辑级联级联缓冲器缓冲器/比较器比较器中断屏蔽寄存器中断屏蔽寄存器 IMR控控 制制 逻逻 辑辑现行现行服务服务寄存器寄存器

3、ISR优先级优先级分析器分析器PR中断中断请求请求寄存器寄存器IRRCAS0CAS1CAS2内部总线内部总线CSINTAINTSP/ END0-D7IR0IR1IR2IR3IR4IR5IR6 IR7RDWRA0Kunming University of Science & TechnologyPage 9Kunming University of Science & TechnologyPage 10Kunming University of Science & TechnologyPage 11Kunming University of Science & T

4、echnologyPage 12Kunming University of Science & TechnologyPage 13Kunming University of Science & TechnologyPage 14Kunming University of Science & TechnologyPage 1512345678910111213142827262524232221201918171615VccA0INTAIR7IR6IR5IR4IR3IR2IR1IR0INTSP/ENCAS2CSWRRDD7D6D5D4D3D2D1D0CAS0CAS1Vss

5、8259AKunming University of Science & TechnologyPage 16【注意注意】：当中断得到响应后，中断输入端必须及时撤出：当中断得到响应后，中断输入端必须及时撤出高电平，否则在高电平，否则在CPU进入中断处理过程，并且开中断的情进入中断处理过程，并且开中断的情况下，原输入端的高电平会引起第二次中断的错误。况下，原输入端的高电平会引起第二次中断的错误。Kunming University of Science & TechnologyPage 17Kunming University of Science & Technology

6、Page 18Kunming University of Science & TechnologyPage 19Kunming University of Science & TechnologyPage 20Kunming University of Science & TechnologyPage 21Kunming University of Science & TechnologyPage 22Kunming University of Science & TechnologyPage 23Kunming University of Scienc

7、e & TechnologyPage 24Kunming University of Science & TechnologyPage 25Kunming University of Science & TechnologyPage 26Kunming University of Science & TechnologyPage 27Kunming University of Science & TechnologyPage 28Kunming University of Science & TechnologyPage 29213Kunming University of Science & TechnologyPage 30Kunming University of Science & Technolo