本文继续介绍Windows Embedded CE 6.0和Windows桌面系统内部一些知识。
Windows Embedded CE 6.0中断机制
下图为Windows Embedded CE 6.0中断模型：
(1).设备发起一个硬件中断。->
(2).内核(Kernel.DLL)响应该中断，并call对应的中断服务例程(ISR)。->
(3).中断服务例程快速处理该中断。->
(4).驱动中的中断服务线程(IST)被通知处理该中断，这里内核使用Event通知IST。
这个过程中涉及到的ISR和IST都会处理中断，但有所不同，前者的中断级别更高，所做的工作也很简单，而后者做主要的处理工作。具体请看以下的介绍。
"Real-time applications use interrupts to respond to external events in a timely manner. To do this, Windows Embedded CE 6.0 breaks interrupt processing into two steps: an interrupt service routine (ISR) and an interrupt service thread (IST). The ISR runs immediately to identify and mask the interrupt, and perform any high priority tasks. The corresponding IST is a normal system thread (although typically of high priority) and can perform the bulk of the handling that is not time critical. This two stage model allows the operating system to maximize the amount of time the system is able to respond to other high priority interrupts.
The kernel is able to handle a total of 64 interrupts from external sources, some of which are predefined (e.g. system timer interrupt, real time clock etc). Devices that have more than 64 interrupt sources that need to be exposed (rare) must implement a mechanism to share interrupt identifiers. Typically this is done by multiplexing related interrupts together in the ISR, and demultiplexing them in the IST.”
关于Windows Embedded CE 6.0中断机制在此就介绍这么多，更详细的内容等我慢慢消化了再介绍。
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