Relocate the INTERRUPT VECTOR

[dan78]

Dear all Hello,

I'm using CodeWarrior 5.9.0 for my application with MC9S12P128.

In my application I need to relocate the interrupt vector address.
For example: I need to put the Timer Overflow Interrupt in the location 0x7FDE.
I've done this by this entry in the .prm file:

VECTOR ADDRESS 0x7FDE TOV_Interrupt

My applicatin runs correctly, even if I reset it by the debugger.
But if i do an hardware reset turning off the power supply, the application doesn't handle the interrupt correctly and it enters in a infinite loop.

Is corretc to use the entry in the .prm file or do I have to use another method?

Thank you.

[Sten · Accepted solution]

Hi DAN78

I assume you are using a bootloader? I am using the same approach: a bootloader in protected flash occupying the address range 0xF800..FFFF. Because the standard vector area is in protected flash, I have relocated my applications vectors to 0xF7xx. In my applications I set the IVBR to 0xF7 before enabling interrupts. But!!! All the Reset-vectors you must handle with your bootloader in the way Lundin suggests. For example the Bootloaders Reset-ISR must, depending of if the bootloader is running or not, either do bootloader-stuff or jump to the address pointed toby the aplications reset-vector (in my case at 0xF7FE).

Hope this helps you to find your problem.

Sten

[dan78]

Hi Sten,

I've just done an example like the way you suggested to me and it works.

Thanks a lot!

[Lundin]

Why on earth would you need to move the vector table? This seems like needless obfuscation to me. Even if you are make some mysterious bootloader, I still don't see the need to move the vector table. Flash the vector table when you switch from bootloader to live application.

Or simpler still:

// prm

VECTOR ADDRESS 0xFFDE TOV_Interrupt

#pragma TRAP_PROC

void TOV_Interrupt (void)

{

  if(something)

   {

    execute_this();

  }

  else

  {

    execute_that();

  }

}

[dan78]

Hi Ludlin,

Yes I've have to use a bootloader.

But I can't flash the vector table when I'm in my main program (bootloader and reset vector are in the same flash bank,

 so i want to flash the vector table I have to erase the whole bolck, erasing the bootloader... )

Thanks