• State Not Answered
  • Locked Locked
  • Replies 5 replies
  • Subscribers 21 subscribers
  • Views 2623 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Changing an Interrupt Vector

Kitty Fields

I have an application that uses CAPCOM Timer 0, and want to change the interrupt vector address during runtime to vector to another function. However, the CAPCOM Interrupt Vector Location is at 80h, which is in Flash. Is there any way to easily change the interrupt vector address for CAPCOM Timer 0?

Parents
  • 0 in reply to Mik Kleshov

    Mike

    Thanks for the reply. The problem is that the interrupt routine is also in flash, and the location of the new interrupt routine is in downloaded RAM, and will change as updates change. I could modify the flash code to jump to a RAM location, and then change the RAM code as needed, but the flash code is already programmed into an existing product, and I'm trying to change the updated application code that is downloaded into RAM. I was somewhat suprised to find that the interrupt vector table was located in flash, since changing interrupt vectors is fairly common. Is there a way to move the entire interrupt table to RAM, and force the CPU to use that table? I know there is a VECTAB linker command, but I don't know if there is a way to implement something like a VECTAB function in C. Thanks.

Reply
  • 0 in reply to Mik Kleshov

    Mike

    Thanks for the reply. The problem is that the interrupt routine is also in flash, and the location of the new interrupt routine is in downloaded RAM, and will change as updates change. I could modify the flash code to jump to a RAM location, and then change the RAM code as needed, but the flash code is already programmed into an existing product, and I'm trying to change the updated application code that is downloaded into RAM. I was somewhat suprised to find that the interrupt vector table was located in flash, since changing interrupt vectors is fairly common. Is there a way to move the entire interrupt table to RAM, and force the CPU to use that table? I know there is a VECTAB linker command, but I don't know if there is a way to implement something like a VECTAB function in C. Thanks.

Children
  • 0 in reply to Kitty Fields

    Is there a way to move the entire interrupt table to RAM, and force the CPU to use that table?

    No, not with the C16x (ST10) family of microcontrollers. If you can't change code in flash, then I can see no way out for you. Unless you have loads of RAM and it's possible to copy the code from flash to RAM and remap RAM to replace flash, including interrupt vector table.

    - mike

  • 0 in reply to Mik Kleshov

    Mike

    Thanks again for the reply. Actually, I do have lots of RAM available. In fact, I have much more RAM than flash, and the RAM program is basically an update of the flash code. So I have enough RAM, and more, to duplicate all the flash code, including the interrupt table. With this configuration, is there a way to startup the whole application from a non-zero memory location which is in RAM? Thanks.

  • 0 in reply to Kitty Fields

    I don't know what particular microcontroller it is and whether the flash memory is internal or external. There is a catch: if it's internal flash memory, then there is no way to remap it at run-time (after the EINIT instruction has been executed.) If it is external flash memory, then remapping RAM in its place should be fairly straightforward.

    - mike