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Forum: ARM programming with GCC/GNU tools Problem getting fiq working with AT91SAM7S256


von Michel B. (vbarre)


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I have no problems with normal interrupts (irqs) but cannot get fast
interrupt (fiq) working. I am using the assembler wrapper code found in
the "MIPS" example. Looking at the wrapper code for fiq
(FIQ_Handler_Entry), I am wondering if it is complete : is it not
supposed to save the LR_fiq in fiq stack at the begining?

Has anybody tested successfully this wrapper ?

Thanks.

Michel

von Martin Thomas (Guest)


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Michel Boulanger wrote:
> I have no problems with normal interrupts (irqs) but cannot get fast
> interrupt (fiq) working. I am using the assembler wrapper code found in
> the "MIPS" example. Looking at the wrapper code for fiq
> (FIQ_Handler_Entry), I am wondering if it is complete : is it not
> supposed to save the LR_fiq in fiq stack at the begining?
>
> Has anybody tested successfully this wrapper ?

I don't think the wrapper itself does cause the problem. I have not used
ARM7 FIQ so far since I did not need it in a project -> I have not
tested the wrapper. But the wrapper seems to handle the "banked" LR
correctly and the LR is also "saved" on the stack before the wrapper
calls the user-function. You may check the stack-setup startup
assembler-code. The startup-code based on examples from Atmel do not
include the "MOV SP,..." for the FIQ stack-setup. The instructions used
for the other stack initialisations can serve as templates for the FIQ
stack-setup

Martin Thomas

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