AVR-Chat

Kathy Quinlan wrote:
> David Kelly wrote:
> 
>>On Jun 5, 2005, at 10:50 AM, Kathy Quinlan wrote:
>>
>>
>>
>>>Hi all,
>>>
>>>I have a problem with a project. I can see the problem externally, I
>>>have a counter that counts from 1 to 255, ticks over to 0 and  
>>>counts up
>>>again....
>>>
>>>Sometimes during the operation, the counter resets to 1 and starts  
>>>again.
>>
>>
>>That sounds a lot like an interrupt vector is undefined by your  
>>application and is executing the default vector which is usually the  
>>startup/initialization code.
>>
>>Its the kind of thing that could be hard to track down. I don't know  
>>of a way for a routine to extract the vector which called it. Write  
>>such a routine and substitute for the default. Otherwise one is stuck  
>>writing a unique IRQ service routine for each and every IRQ vector.  
>>Do something unique in each routine and you'll know which is getting  
>>dispatched.
> 
> 
> 
> This is in CodeVision C, so I am sure all unused interrupts are just 
> reti instructions, but I will check :)
> 
> Regards,
> 
> Kat.

F*&K that is not good, I just checked the .lst file, and all UNUSED 
interrupts jump to 0x0000 ie the RESET VECTOR.

I think this is a very poor way to handle things.

now to track down the phantom interrupt :(

Regards,

Kat.