Embedded Systems Design, 2nd Edition

258 Embedded systems design

Within Windows NT, the interrupt processing is also sub-

ject to the multitasking priority levels. Depending on how these

are assigned to the interrupt priority levels, the processing of a

high priority interrupt may be delayed until a higher priority

process has completed. It makes sense therefore to have high

priority interrupts processed by processes with high priority

scheduling levels. Comparing the interrupts and the priority

levels shows that this maxim has been followed. Software inter-

rupts used to communicate between processes are allocated both

low interrupt and scheduling priorities. Time critical interrupts

such ...