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Architectures and Processors forum How to relocate the Cortex-M3 Vector Table

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How to relocate the Cortex-M3 Vector Table

Offline Davide Masi over 9 years ago

Note: This was originally posted on 9th November 2011 at http://forums.arm.com

Hello,
I am Davide Masi and I work on Fujitsu based on ARM Cortex M3.

How do I relocate the interrupt vector table from address 0x0000 to a different address, for examples in RAM?
Where can I find examples or AN about the problem?

Thanks

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Offline Joseph Yiu over 9 years ago +2 verified

Note: This was originally posted on 11th November 2011 at http://forums.arm.com Let's say you want to relocate vector table from flash to SRAM: - reserve an area in SRAM for Vector table when you setup...

0 Offline Davide Masi over 9 years ago

Note: This was originally posted on 10th November 2011 at http://forums.arm.com

Is possible to relocate the vector table also in run-time?

Thanks
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0 Offline Davide Masi over 9 years ago

Note: This was originally posted on 11th November 2011 at http://forums.arm.com

What steps should I follow to reallocate the table of vectors?
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0 Offline Joseph Yiu over 9 years ago

Note: This was originally posted on 10th November 2011 at http://forums.arm.com

Hi David,
Welcome to the forum.

Maybe you can use the Vector Table Offset Register (VTOR) to do this.

http://infocenter.arm.com/help/topic/com.arm.doc.dui0552a/Ciheijba.html

Examples can be found in various forums by searching for "SCB->VTOR".
One example is on Keil forum: http://www.keil.com/forum/17484/

regards,
Joseph
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0 Offline Joseph Yiu over 9 years ago

Note: This was originally posted on 10th November 2011 at http://forums.arm.com

Yes, VTOR can be programmed at run time.
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+1 Offline Joseph Yiu over 9 years ago

Note: This was originally posted on 11th November 2011 at http://forums.arm.com

Let's say you want to relocate vector table from flash to SRAM:
- reserve an area in SRAM for Vector table when you setup your project (tool chain dependent). This area need to align with the size of the table (see the link I provided in previous message).
- during run time, copy the vector table from flash to the reserved vector table area, and then modify the vector entry you need to change if required.
- write the new vector table address to VTOR.
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