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pic18fxx and interupt

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ect_09

New Member
Hi
i studied Pic 18f458 interupts.
i use
1-#pragma interrupt chk_isr
void chk_isr(void)
2-#pragma code my_HiPrio_int=0x08
void my_HiPrio_int(void)
3-#pragma code
void main()

please tell me why we use it.
 

Ian Rogers

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Most Helpful Member
The correct way to declare an interrupt in C18 is:-

Code:
#pragma code InterruptVectorHigh = 0x08
This instructs the compiler to the CODE section at address 0x08 ( low interrupt vector )
Code:
void InterruptVectorHigh (void)
{
  _asm
    goto InterruptHandlerHigh //jump to interrupt routine
  _endasm
}
This places the new vector in that code space (InterruptHandlerHigh can be any function identifier )

Now vector 0x08 in code will hold the jump call to YOUR interrupt routine.

Code:
#pragma code
#pragma interrupt InterruptHandlerHigh

void InterruptHandlerHigh ()
	{
         // your code here...
         }
The final piece, is a function in CODE space that contains the code that needs executing when a interrupt is fired.
 
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