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Nested Interrupts

Hello everybody,
I'm using LPC2148 ARM7, programming with uVision3.

Now, I need nesting Interrupts. Following lines were used:

                AREA    NESTED_IRQ, CODE, READONLY
                ARM

                                EXPORT  nested_irq_enable
                                EXPORT  nested_irq_disable



nested_irq_enable                       ; Nested Interrupts Entry:

                                MRS             LR, SPSR
                                STMFD   SP!, {LR}
                                MSR             CPSR_c, #0x1F
                                STMFD   SP!, {LR}



nested_irq_disable                      ; Nested Interrupts Exit:

                                ldmfd   sp!, {lr}
                                msr             cpsr_c, #0x92
                                ldmfd   sp!, {lr}
                                msr             spsr_cxsf, lr


;/*****************************************************************************/

                END

Now, my Controller runs always in Prefetch Abort Handler. Does anybody know this problem?
Or does anybody see what I'm doing wrong?

Thanks for all Replys, Adrian

0 Tamiryan Michael over 13 years ago

I never tested this code:

void __asm enable_nested_interrupts(void)
{
    MOV     R0, LR

    MRS     LR, SPSR                ; Copy SPSR_irq to LR
    PUSH    {LR}                    ; Save SPSR_irq
    MSR     CPSR_c, #0x1F           ; Enable IRQ (Sys Mode)
    PUSH    {LR}                    ; Save LR

    MOV     LR, R0

    BX LR
}

void __asm disable_nested_interrupts(void)
{
    MOV     R0, LR

    POP     {LR}                    ; Restore LR
    MSR     CPSR_c, #0x92           ; Disable IRQ (IRQ Mode)
    POP     {LR}                    ; Restore SPSR_irq to LR
    MSR     SPSR_cxsf, LR           ; Copy LR to SPSR_irq

    MOV     LR, R0

    BX LR
}

0 A. M. over 13 years ago in reply to Tamiryan Michael

Hello Tamir, Thanks for Reply!
I tested your routines, but I have now some strange Problems:
When the Nested Interrupts were used, the Stack Pointer go into a unused routine and the uC hangs himself up... Or in tech. Language: The Controller runs into an endless Loop, even though this Loop isn't used...
Do I have some Problems with Function calls? Or what?!?

Have anybody (Tamir =) an Idea?

Thanks for Replys,
Adrian
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0 Tamiryan Michael over 13 years ago in reply to A. M.

You must make sure you have enough stack space - don't forget that all interrupts will use IRQ mode stack by default.
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0 A. M. over 13 years ago in reply to Tamiryan Michael

The biggest Object I use is a String FIFO which's declarated as a Global Structure... Otherwise I don't use big Variables. Where can I look how much Memory Space I use?

PS: I found an other routine and this is running!!
It was the Nested Interrupt handling who crashed my programme =)
Thanks a lot for your help

Adrian
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0 A. M. over 13 years ago in reply to A. M.

Oh, sorry:
My Solution was this Link:

http://www.keil.com/support/docs/3353.htm

Thanks again!
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