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Nested Interrupt Question

Hi,

I have very long function that I want to be executed on time, even if other long functions (less important) are running in my main loop.

So my Idea was to write this function in an interrupt, that can be interrupted by my other, short interrupts (communication etc.)

I am trying to use the IENABLE and IDISABLE macros for the interruptable interrupt, but they don't seem to have any effect (or even cause crashes)

I'm using STR91FAM with uvision3 and ARM-ELF-GCC

Any ideas?

Parents

0 Andreas Pennekamp over 15 years ago in reply to Tamir Michael

Those functions look pretty much like the macros I'm already using:


#define IENABLE asm(" MRS LR, SPSR"); /* Copy SPSR_irq to LR */ \ 
asm("STMFD SP!, {LR} "); /* Save SPSR_irq */ \ 
asm("MSR CPSR_c, #0x1F "); /* Switch to SYS mode with IRQ enabled*/ \ 
asm("STMFD SP!, {LR} ") ; /* Save SYS mode LR */

#define IDISABLE asm("LDMFD SP!, {LR}") ; /* Restore SYS mode LR */ \ 
asm("MSR CPSR_c, #0x92") ; /* Switch to IRQ mode with IRQ disabled*/ \ 
asm("LDMFD SP!, {R0}") ; /* Restore SPSR_irq to R0 */ \ 
asm("MSR SPSR_cxsf, R0") ; /* Copy R0 to SPSR_irq */

I want to call my big function whenever a complete data package is received via SPI, so I placed these lines at the end of the SPI interrupt:

if(SPI_TransferCompleted)
{
   SPI_TransferCompleted = 0;
   IENABLE;
   BigFunction();
   IDISABLE;
}
// write any value to VIC1 VAR
VIC1->VAR = 0xFF;

I can compile this, but the controller behaves awkwardly and crashes after a few seconds

Reply

0 Andreas Pennekamp over 15 years ago in reply to Tamir Michael

Those functions look pretty much like the macros I'm already using:


#define IENABLE asm(" MRS LR, SPSR"); /* Copy SPSR_irq to LR */ \ 
asm("STMFD SP!, {LR} "); /* Save SPSR_irq */ \ 
asm("MSR CPSR_c, #0x1F "); /* Switch to SYS mode with IRQ enabled*/ \ 
asm("STMFD SP!, {LR} ") ; /* Save SYS mode LR */

#define IDISABLE asm("LDMFD SP!, {LR}") ; /* Restore SYS mode LR */ \ 
asm("MSR CPSR_c, #0x92") ; /* Switch to IRQ mode with IRQ disabled*/ \ 
asm("LDMFD SP!, {R0}") ; /* Restore SPSR_irq to R0 */ \ 
asm("MSR SPSR_cxsf, R0") ; /* Copy R0 to SPSR_irq */

I want to call my big function whenever a complete data package is received via SPI, so I placed these lines at the end of the SPI interrupt:

if(SPI_TransferCompleted)
{
   SPI_TransferCompleted = 0;
   IENABLE;
   BigFunction();
   IDISABLE;
}
// write any value to VIC1 VAR
VIC1->VAR = 0xFF;

I can compile this, but the controller behaves awkwardly and crashes after a few seconds

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