> From: Mervin J > > As you told, there is some problem with stack pointer handling.Since > the program behavior is not predicable with FIQ but works well with IRQ. > How can i handle FIQ as it is,without taking it to IRQ level.
I'm wondering why you're using FIQ at all. The only legitimate reason I can think of for trying to get FIQ to invoke an eCos ISR is that you've got some external device that's hard-wired to the FIQ pin, and you can't change the board. Otherwise, if you don't mind the overhead of the standard eCos ISR/DSR mechanism, then you'd do better to use a regular interrupt. (Remember, you can make any PIO line an interrupt input, although all such PIO lines would share an ISR.) If you're using FIQ because you want the lower overhead, then routing it to an ISR is probably not what you want. FIQ is most useful for implementing a software-based smart DMA-like system, where the only thing the FIQ handler does is some simple I/O, and not invoking an ISR until some buffer is full or empty. In that case, you should be writing it in assembler. -- Ciao, Paul D. DeRocco Paul mailto:[email protected] -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
